Immunogenic compositions for inducing an immune response for elimination of senescent cells

This application is a U.S. national stage entry under 35 USC § 371 of PCT/US2013/072938, filed Dec. 3, 2013, which claims the benefit of U.S. Provisional Application No. 61/747,653, filed Dec. 31, 2012, and U.S. Provisional Application No. 61/732,746, filed Dec. 3, 2012, the contents of which are herein incorporated by reference in their entirety.

The Sequence Listing associated with this application is provided in text format in lieu of a paper copy, and is hereby incorporated by reference into the specification. The name of the text file containing the Sequence Listing is 200201_412WO_SEQUENCE_LISTING.txt. The text file is 1 KB, was created on Dec. 3, 2013 and is being submitted electronically via EFS-Web.

The disclosure herein relates generally to immunogenic compositions (e.g., vaccines) and methods for using the immunogenic compositions for inducing an immune response directed specifically against senescent cells for treatment and prophylaxis of age-related diseases and disorders, and other diseases and disorders associated or exacerbated by the presence of senescent cells.

Senescent cells accumulate in tissues and organs of individuals as they age and are found at sites of age-related pathologies. While senescent cells are believed important to inhibiting proliferation of dysfunctional or damaged cells and particularly to constraining development of malignancy (see, e.g., Campisi, Curr. Opin. Genet. Dev. 21:107-12 (2011); Campisi, Trends Cell Biol. 11:S27-31 (2001); Prieur et al., Curr. Opin. Cell Biol. 20:150-55 (2008)), the presence of senescent cells in an aging individual may contribute to aging and aging-related dysfunction (see, e.g., Campisi, Cell 120:513-22 (2005)). Given that senescent cells have been causally implicated in certain aspects of age-related decline in health and may contribute to certain diseases, and are also induced as a result of necessary life-preserving chemotherapeutic and radiation treatments, the presence of senescent cells may have deleterious effects to millions of patients worldwide (e.g., fatigue, weakness, loss of physical agility, decrease in cognitive function). Accordingly, treatments aimed at clearing aging-induced and therapy-induced senescent cells and improving age-sensitive traits have the potential to markedly improve the health, lifespan, and quality of life for patients exposed to senescence-inducing stimuli. The present disclosure addresses these needs and offers numerous related advantages.

Disclosed herein are immunogenic compositions and methods of using the compositions for inducing an immune response that is specific for senescent cells (i.e., specific for senescent cell associated antigens expressed by the senescent cells) and that comprises clearance (i.e., removal, elimination) of senescent cells from the subject receiving the immunogenic composition. The methods include active and passive immunization. Provided herein are the following embodiments.

In one embodiment, a method is provided for evoking an immune response specific for a senescent cell in a subject, wherein the immune response comprises clearance of the senescent cell by the immune system of the subject, wherein the method comprises administering to the subject an immunogenic composition comprising: (a) a pharmaceutically acceptable excipient, and (b) an immunogen. In particular embodiments, the immunogen is selected from (i) an isolated senescent cell-associated antigen or an antigenic fragment thereof, wherein the senescent cell-associated antigen is selected from (A) p16INK4a, (B) a senescent cell-associated antigen selected from Table 1, and (C) a senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 or Table 3, and wherein the antigenic fragment comprises at least 20 contiguous amino acids of the senescent cell-associated antigen; (ii) an isolated polynucleotide encoding at least two senescent cell-associated antigens of (i) or antigenic fragments thereof; (iii) at least two isolated polynucleotides, wherein a first isolated polynucleotide encodes a first senescent cell-associated antigen or an antigenic fragment thereof, and wherein the first senescent cell-associated antigen is selected from (A) p16INK4a, (B) a senescent cell-associated antigen selected from Table 1, and (C) a senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 or Table 3, and wherein the antigenic fragment comprises at least 20 contiguous amino acids of the first senescent cell-associated antigen, and a second polynucleotide encodes a second senescent cell-associated antigen, wherein the second senescent cell-associated antigen is selected from (A) p16INK4a, (B) a senescent cell-associated antigen selected from Table 1, and (C) a senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 or Table 3, and wherein the antigenic fragment comprises at least 20 contiguous amino acids of the second senescent cell-associated antigen; (iv) a recombinant expression vector that is a viral vector comprising a polynucleotide that encodes the senescent cell-associate antigen or antigenic fragment thereof of (i); (v) a senescent cell membrane preparation, a senescent cell organelle preparation, or an exosome; (vi) a fusion polypeptide comprising at least two senescent cell-associated antigens, wherein each of the at least two senescent cell-associated antigens are different and each is selected from (A) p16INK4a, (B) a senescent cell-associated antigen selected from Table 1, and (C) a senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 or Table 3; (vii) a fusion polypeptide comprising at least two antigenic fragments wherein each of the at least two antigenic fragments comprises at least 20 contiguous amino acids of a senescent cell-associated antigen selected from (A) p16INK4a, (B) a senescent cell-associated antigen selected from Table 1, and (C) a senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 or Table 3; (viii) a fusion polypeptide comprising at least one senescent cell-associated antigen of (i) or an antigenic fragment thereof and a co-stimulatory polypeptide; and (ix) a modified dendritic cell wherein a dendritic cell is isolated from the subject and is modified by (A) introducing a senescent cell-associated antigen, or an antigenic fragment that comprises at least 20 contiguous amino acids of the senescent cell-associated antigen, wherein the senescent cell-associated antigen is selected from (A) p16INK4a, (B) a senescent cell-associated antigen selected from Table 1, and (C) a senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 or Table 3, or (B) introducing a polynucleotide encoding the senescent cell-associated antigen, or an antigenic fragment of (A), into the dendritic cell ex vivo to provide a modified dendritic cell, and wherein the modified dendritic cell is administered to the subject. In certain particular embodiments for use in the methods described above and herein, the senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 is any one of ADAMTS7, APLP2, ATP6V0D2, BCHE, C11orf87, CD46, CYB5D2, FBXL7, GPR137B, IFI27L1, IL15RA, LAMP2, MYO10, NEU1, NHSL2, NPAS2, OR1F1, PEA15, RAB23, RARB, RNPC3, SELO, SELT, SEMA5B, SERP1, SERPINE1, SLC9A7, SNX3, TBC1D1, TBRG1, TCEANC, TFPI, TNFAIP1, TUBG2, USP18, or ZNF419 (see Table 2). In other more specific embodiments, the senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 is any one of NEU1, SELO, SERP1, SERPINE1, or SNX3. In other specific embodiments, the senescent cell-associated antigen is p16INK4a. In other certain particular embodiments, the at least first and the at least second senescent cell-associated antigen encoded by a nucleic acid sequence selected from Table 2 are different and selected from any one of ADAMTS7, APLP2, ATP6V0D2, BCHE, C11orf87, CD46, CYB5D2, FBXL7, GPR137B, IFI27L1, IL15RA, LAMP2, MYO10, NEU1, NHSL2, NPAS2, OR1F1, PEA15, RAB23, RARB, RNPC3, SELO, SELT, SEMA5B, SERP1, SERPINE1, SLC9A7, SNX3, TBC1D1, TBRG1, TCEANC, TFPI, TNFAIP1, TUBG2, USP18, and ZNF419 (see Table 2). In other more specific embodiments, the at least first and the at least second senescent cell-associated antigens encoded by a nucleic acid sequence selected from Table 2 is selected from any one of NEU1, SELO, SERP1, SERPINE1, and SNX3. In still other particular embodiments, the at least first senescent cell-associated antigen or the at least second senescent cell-associated antigen is p16INK4a.

In certain other embodiments of the method described above and herein, the immunogen comprises at least two isolated senescent cell-associated antigens or antigenic fragments thereof, wherein (a) a first isolated senescent cell-associated antigen, or an antigenic fragment thereof that comprises at least 20 contiguous amino acids of the first senescent cell-associated antigen, and (b) a second isolated senescent cell-associated antigen or an antigenic fragment thereof that comprises at least 20 contiguous amino acids of the second senescent cell-associated antigen, are different and each independently is selected from (A) p16INK4a, (B) a senescent cell-associated antigen selected from Table 1, and (C) a senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 or Table 3. In certain particular embodiments, the at least first and the at least second isolated senescent cell-associated antigen are different and encoded by a nucleic acid sequence selected from Table 2, wherein the at least first and the at least second isolated senescent cell-associated antigens are selected from ADAMTS7, APLP2, ATP6V0D2, BCHE, C11orf87, CD46, CYB5D2, FBXL7, GPR137B, IFI27L1, IL15RA, LAMP2, MYO10, NEU1, NHSL2, NPAS2, OR1F1, PEA15, RAB23, RARB, RNPC3, SELO, SELT, SEMA5B, SERP1, SERPINE1, SLC9A7, SNX3, TBC1D1, TBRG1, TCEANC, TFPI, TNFAIP1, TUBG2, USP18, and ZNF419 (see Table 2). In other more specific embodiments, the at least first and the at least second isolated senescent cell-associated antigens encoded by a nucleic acid sequence from Table 2 are selected from NEU1, SELO, SERP1, SERPINE1, and SNX3. In still other particular embodiments, the at least first senescent cell-associated antigen or the at least second senescent cell-associated antigen is p16INK4a.

In a more particular embodiment, the senescent cell-associated antigen is present on the cell surface of the senescent cell. In still another embodiment, when the immunogen comprises a first and the second senescent cell-associated antigen, the first and the second senescent cell-associated antigen are each present on the cell surface of the senescent cell.

In certain other embodiments, the immunogenic composition comprises a recombinant expression vector that comprises the polynucleotide of (b)(ii) operatively linked to at least one regulatory expression sequence. In a more particular embodiment, the recombinant expression vector is a viral vector. In still another specific embodiment, the viral vector is selected from an adenovirus vector, lentivirus vector, a herpes virus vector, adenovirus-associated vector, or a poxvirus vector. In another particular embodiment, the adenoviral vector is a replication-defective adenovirus. In certain specific embodiment, the replication-defective adenovirus is a recombinant human adenovirus having a serotype selected from Ad11, Ad24, Ad26, Ad34, Ad35, Ad48, Ad49, and Ad50.

In yet another embodiment of the method described above and herein, the immunogen comprises at least one polynucleotide that encodes (a) a first senescent cell-associated antigen, or an antigenic fragment thereof that comprises at least 20 contiguous amino acids of the first senescent cell-associated antigen, and (b) a second senescent cell-associated antigen or an antigenic fragment thereof that comprises at least 20 contiguous amino acids of the second senescent cell-associated antigen, wherein the first and second senescent cell-associated antigens are different and each independently is selected from (A) p16INK4a, (B) a senescent cell-associated antigen selected from Table 1, and (C) a senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 or Table 3. In certain particular embodiments, the at least first and the at least second isolated senescent cell-associated antigen are encoded by a nucleic acid sequence selected from Table 2, wherein the at least first and the at least second isolated senescent cell-associated antigens are selected from ADAMTS7, APLP2, ATP6V0D2, BCHE, C11orf87, CD46, CYB5D2, FBXL7, GPR137B, IFI27L1, IL15RA, LAMP2, MYO10, NEU1, NHSL2, NPAS2, OR1F1, PEA15, RAB23, RARB, RNPC3, SELO, SELT, SEMA5B, SERP1, SERPINE1, SLC9A7, SNX3, TBC1D1, TBRG1, TCEANC, TFPI, TNFAIP1, TUBG2, USP18, and ZNF419 (see Table 2). In other more specific embodiments, the at least first and the at least second isolated senescent cell-associated antigens encoded by a nucleic acid sequence from Table 2 are selected independently from NEU1, SELO, SERP1, SERPINE1, and SNX3. In still other particular embodiments, the at least first senescent cell-associated antigen or the at least second senescent cell-associated antigen is p16INK4a. In still another embodiment, the immunogenic composition comprises a recombinant expression vector that comprises the at least one polynucleotide operatively linked to at least one regulatory expression sequence. In certain embodiments, the recombinant expression vector is a viral vector. In still another specific embodiment, the viral vector is selected from an adenovirus vector, lentivirus vector, a herpes virus vector, adenovirus-associated vector, or a poxvirus vector. In another particular embodiment, the adenoviral vector is a replication-defective adenovirus. In certain specific embodiment, the replication-defective adenovirus is a recombinant human adenovirus having a serotype selected from Ad11, Ad24, Ad26, Ad34, Ad35, Ad48, Ad49, and Ad50.

In yet another embodiment of the method described above and herein, the immunogen comprises at least two polynucleotides wherein a first polynucleotide encodes the first senescent cell-associated antigen, or an antigenic fragment thereof, and a second polynucleotide encodes the second senescent cell-associated antigen, or an antigenic fragment thereof. In a specific embodiment, the immunogenic composition comprises (a) a recombinant expression vector that comprising the at least two polynucleotides wherein each of the at least two polynucleotides is operatively linked to at least one regulatory expression sequence; or (b) a first recombinant expression vector that comprises the first polynucleotide operatively linked to at least one regulatory expression sequence and a second recombinant expression vector that comprises the first polynucleotide operatively linked to at least one regulatory expression sequence. In certain embodiments, the recombinant expression vector is a viral vector. In still more particular embodiments, the recombinant expression vector of (a) the first recombinant expression vector of (b) and the second recombinant expression vector of (b) are each a viral vector. In still another specific embodiment, the viral vector is selected from an adenovirus vector, lentivirus vector, a herpes virus vector, adenovirus-associated vector, or a poxvirus vector. In another particular embodiment, the adenoviral vector is a replication-defective adenovirus. In certain specific embodiment, the replication-defective adenovirus is a recombinant human adenovirus having a serotype selected from Ad11, Ad24, Ad26, Ad34, Ad35, Ad48, Ad49, and Ad50. In one particular embodiment, the first recombinant expression vector and the second recombinant expression vector are each the same or different recombinant human adenoviral vector having a serotype independently selected from Ad11, Ad24, Ad26, Ad34, Ad35, Ad48, Ad49, and Ad50.

In yet another embodiment of the method described above and herein, when the immunogen comprises a dendritic cell, the dendritic cell is modified by introducing a recombinant expression vector comprising the polynucleotide. In certain embodiments, the recombinant expression vector is a viral vector selected from an adenovirus vector, lentivirus vector, a herpes virus vector, adenovirus-associated vector, or a poxvirus vector. In another particular embodiment, the adenoviral vector is a replication-defective adenovirus. In certain specific embodiment, the replication-defective adenovirus is a recombinant human adenovirus having a serotype selected from Ad11, Ad24, Ad26, Ad34, Ad35, Ad48, Ad49, and Ad50.

In particular embodiments, with respect to the methods described above and herein, the immunogenic composition further comprises a pharmaceutically acceptable adjuvant. In other particular embodiments, with respect to the methods described above and herein, the immunogenic composition further comprises (a) a co-stimulatory polypeptide that enhances the adaptive immune response to the immunogen; (b) a polynucleotide encoding the co-stimulatory polypeptide; or (c) a recombinant expression vector that comprises the polynucleotide sequence, which is operatively linked to at least one regulatory expression sequence. In still other specific embodiments, the subject has or is at risk of developing a disease or disorder treatable by clearing senescent cells from a tissue of the subject. In still more specific embodiments, of the methods described above and herein, the disease or disorder is an age-related disease or disorder.

Also provided herein is an immunogenic composition that comprises a pharmaceutically acceptable excipient and at least one immunogenic preparation selected from: (a) an immunogenic preparation comprising a first isolated senescent cell-associated antigen, or an antigenic fragment thereof that comprises at least 20 contiguous amino acids of the first senescent cell-associated antigen, and a second isolated senescent cell-associated antigen or an antigenic fragment thereof that comprises at least 20 contiguous amino acids of the second senescent cell-associated antigen, wherein the first and second senescent cell-associated antigens are different and selected independently from p16INK4a, a senescent cell-associated antigen selected from Table 1, and a senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 or Table 3; (b) an immunogenic preparation comprising at least one polynucleotide that encodes the first senescent cell-associated antigen, or an antigenic fragment thereof, and the second senescent cell-associated antigen or an antigenic fragment thereof; (c) an immunogenic preparation comprising at least two polynucleotides wherein a first polynucleotide encodes the first senescent cell-associated antigen, or an antigenic fragment thereof, and a second polynucleotide encodes the second senescent cell-associated antigen, or an antigenic fragment thereof; (d) an immunogenic preparation comprising a senescent cell membrane preparation, a senescent cell organelle preparation, or an exosome; (e) an immunogenic preparation comprising a fusion polypeptide comprising at least two senescent cell-associated antigens, wherein each of the at least two senescent cell-associated antigens are different and selected independently from p16INK4a, a senescent cell-associated antigen selected from Table 1, and a senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 or Table 3; (f) an immunogenic preparation comprising a fusion polypeptide comprising at least two antigenic fragments wherein each of the at least two antigenic fragments comprises at least 20 contiguous amino acids of a senescent cell-associated antigen selected from p16INK4a, a senescent cell-associated antigen selected from Table 1, and a senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 or Table 3; and (g) an immunogenic preparation comprising a modified dendritic cell wherein a dendritic cell is isolated from the subject and is modified by (i) introducing a senescent cell-associated antigen, or an antigenic fragment that comprises at least 20 contiguous amino acids of the senescent cell-associated antigen, wherein the senescent cell-associated antigen is selected from (A) p16INK4a, (B) a senescent cell-associated antigen selected from Table 1, and (C) a senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 or Table 3, or (ii) introducing a polynucleotide encoding the senescent cell-associated antigen, or an antigenic fragment of (i), into the dendritic cell ex vivo to provide a modified dendritic cell, and wherein the modified dendritic cell is administered to the subject. In certain particular embodiments, the senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 is any one of ADAMTS7, APLP2, ATP6V0D2, BCHE, C11orf87, CD46, CYB5D2, FBXL7, GPR137B, IFI27L1, IL15RA, LAMP2, MYO10, NEU1, NHSL2, NPAS2, OR1F1, PEA15, RAB23, RARB, RNPC3, SELO, SELT, SEMA5B, SERP1, SERPINE1, SLC9A7, SNX3, TBC1D1, TBRG1, TCEANC, TFPI, TNFAIP1, TUBG2, USP18, or ZNF419 (see Table 2). In other more specific embodiments, the senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 is any one of NEU1, SELO, SERP1, SERPINE1, or SNX3. In other specific embodiments, the senescent cell-associated antigen is p16INK4a. In other certain particular embodiments, the at least first and the at least second senescent cell-associated antigen encoded by a nucleic acid sequence selected from Table 2 are different and selected from any one of ADAMTS7, APLP2, ATP6V0D2, BCHE, C11orf87, CD46, CYB5D2, FBXL7, GPR137B, IFI27L1, IL15RA, LAMP2, MYO10, NEU1, NHSL2, NPAS2, OR1F1, PEA15, RAB23, RARB, RNPC3, SELO, SELT, SEMA5B, SERP1, SERPINE1, SLC9A7, SNX3, TBC1D1, TBRG1, TCEANC, TFPI, TNFAIP1, TUBG2, USP18, and ZNF419 (see Table 2). In other more specific embodiments, the at least first and the at least second senescent cell-associated antigens encoded by a nucleic acid sequence selected from Table 2 is selected from any one of NEU1, SELO, SERP1, SERPINE1, and SNX3. In still other particular embodiments, the at least first senescent cell-associated antigen or the at least second senescent cell-associated antigen is p16INK4a.

In particular embodiments, with respect to the immunogenic composition described above and herein, the senescent cell-associated antigen is present on the cell surface of the senescent cell. In another particular embodiment, the first and the second senescent cell-associated antigen are each present on the cell surface of the senescent cell. In yet another specific embodiment, (i) a recombinant expression vector comprises the at least one polynucleotide of (b) operatively linked to at least one regulatory expression sequence; or (ii) a recombinant expression vector comprises the at least two polynucleotides of (c), wherein each polynucleotide is operatively linked to at least one regulatory expression sequence; or (iii) the dendritic cell is modified by introducing a recombinant expression vector comprising the polynucleotide; or (iv) a first recombinant expression vector comprises the first polynucleotide of (c) and a second recombinant expression vector comprises the second polynucleotide of (c). In particular embodiments, the recombinant expression vector of (i), (ii), and (iii), and the first and second recombination vectors of (iv) are each a viral vector. In certain embodiments, the recombinant expression vector is a viral vector selected from an adenovirus vector, lentivirus vector, a herpes virus vector, adenovirus-associated vector, or a poxvirus vector. In another particular embodiment, the adenoviral vector is a replication-defective adenovirus. In certain specific embodiment, the replication-defective adenovirus is a recombinant human adenovirus having a serotype selected from Ad11, Ad24, Ad26, Ad34, Ad35, Ad48, Ad49, and Ad50.

In certain particular embodiments described above and herein, the immunogenic composition further comprises (a) a co-stimulatory polypeptide that enhances the adaptive immune response to the immunogen; (b) a polynucleotide encoding the co-stimulatory polypeptide; or (c) a recombinant expression vector that comprises the polynucleotide sequence encoding the co-stimulatory polypeptide, which is operatively linked to at least one regulatory expression sequence. In still other embodiments, the immunogenic compositions described above and herein further comprise a pharmaceutically acceptable adjuvant.

In yet another embodiment, a recombinant antibody is provided that comprises (a) at least one immunoglobulin variable region domain that specifically binds to a senescent cell-associated antigen selected from (A) p16INK4a, (B) a senescent cell-associated antigen selected from Table 1, and (C) a senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 or Table 3; and (b) a modified human Fc region that exhibits enhanced affinity for an Fcγ receptor. In a particular embodiment, the recombinant antibody further comprises a second immunoglobulin variable region (Fv), wherein the second variable region specifically binds to the same or a different senescent cell-associated antigen selected from p16INK4a, a senescent cell-associated antigen selected from Table 1, and a senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 or Table 3. Also provided is an immunogenic composition that comprises the recombinant antibody described above and herein and a pharmaceutically acceptable carrier. In still another embodiment, a method is provided for facilitating clearance of a senescent cell from a subject, comprising administering to the subject the immunogenic composition comprising the recombinant antibody described above and herein. In certain particular embodiments, the senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 is any one of ADAMTS7, APLP2, ATP6V0D2, BCHE, C11orf87, CD46, CYB5D2, FBXL7, GPR137B, IFI27L1, IL15RA, LAMP2, MYO10, NEU1, NHSL2, NPAS2, OR1F1, PEA15, RAB23, RARB, RNPC3, SELO, SELT, SEMA5B, SERP1, SERPINE1, SLC9A7, SNX3, TBC1D1, TBRG1, TCEANC, TFPI, TNFAIP1, TUBG2, USP18, or ZNF419 (see Table 2); In other more specific embodiments, the senescent cell-associated antigen that is encoded by a nucleic acid sequence selected from Table 2 is any one of NEU1, SELO, SERP1, SERPINE1, or SNX3. In still other specific embodiments, the senescent cell-associated antigen is p16INK4a.

In one embodiment, a process is provided for formulating the immunogenic composition described above and herein, comprising (a) producing the immunogenic preparation that comprises the first isolated senescent cell-associated antigen, or an antigenic fragment thereof, and the second isolated senescent cell-associated antigen or an antigenic fragment thereof, each as described above and herein, by (i) culturing a first host cell into which a recombinant expression vector comprising at least one regulatory expression sequence operatively linked to a nucleotide sequence that encodes the first senescent cell-associated antigen, or an antigenic fragment thereof in a medium and for a time sufficient to produce the first senescent cell-associated antigen; and (ii) culturing a second host cell into which a recombinant expression vector comprising at least one regulatory expression sequence operatively linked to a nucleotide sequence that encodes the second senescent cell-associated antigen, or an antigenic fragment thereof in a medium and for a time sufficient to produce the second senescent cell-associated antigen; (iii) isolating the first senescent cell-associated antigen from the first host cell culture, and isolating the second senescent cell-associated antigen from the second host cell culture; and (c) formulating the first and the second cell-associated antigens with a pharmaceutically acceptable excipient. In a particular embodiment, the medium is a serum-free medium.

Uses of the immunogenic compositions described above are also provided for evoking an immune response specific for a senescent cell in a subject, wherein the immune response comprises clearance of the senescent cell by the immune system of the subject, and for the manufacture of a medicament for evoking an immune response specific for a senescent cell in a subject, wherein the immune response comprises clearance of the senescent cell by the immune system.

In the following description, certain specific details are set forth in order to provide a thorough understanding of various embodiments. However, one skilled in the art will understand that the invention may be practiced without these details. In other instances, well-known structures have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the embodiments. Unless the context requires otherwise, throughout the specification and claims which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense, that is, as “including, but not limited to.” In addition, the term “comprising” (and related terms such as “comprise” or “comprises” or “having” or “including”) is not intended to exclude that in other certain embodiments, for example, an embodiment of any composition of matter, composition, method, or process, or the like, described herein, may “consist of” or “consist essentially of” the described features. Headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed embodiments.

Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

Also, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to “a non-human animal” may refer to one or more non-human animals, or a plurality of such animals, and reference to “a cell” or “the cell” includes reference to one or more cells and equivalents thereof (e.g., plurality of cells) known to those skilled in the art, and so forth. When steps of a method are described or claimed, and the steps are described as occurring in a particular order, the description of a first step occurring (or being performed) “prior to” (i.e., before) a second step has the same meaning if rewritten to state that the second step occurs (or is performed) “subsequent” to the first step. The term “about” when referring to a number or a numerical range means that the number or numerical range referred to is an approximation within experimental variability (or within statistical experimental error), and thus the number or numerical range may vary between 1% and 15% of the stated number or numerical range. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. The term, “at least one,” for example, when referring to at least one compound or to at least one composition, has the same meaning and understanding as the term, “one or more.”

As used herein, the term “isolated” means that a material (such as a senescent cell-associated antigen or a polynucleotide encoding same) is removed from its original environment (e.g., the natural environment if it is naturally occurring). For example, a naturally occurring nucleic acid or polypeptide present in a living animal is not isolated, but the same nucleic acid or polypeptide, separated from some or all of the co-existing materials in the natural system, is isolated. An “isolated” nucleic acid could be part of a vector and/or such nucleic acid or polypeptide could be part of a composition, and still be isolated in that the vector or composition is not part of the natural environment for the nucleic acid or polypeptide. The term “gene” means the segment of DNA involved in producing a polypeptide chain; it includes regions preceding and following the coding region “leader and trailer” as well as intervening sequences (introns) between individual coding segments (exons). Amino acids may be referred to herein according to the single letter and three letter codes, which are understood according to common textbook knowledge in the art, and therefore with which a person skilled in the art is familiar. The term “fusion polypeptide” used herein may also be used interchangeably with “fusion protein,” and unless specifically indicated otherwise, the two terms are not meant to indicate molecules that have distinguishable properties or characteristics.

Provided herein are immunogenic compositions (e.g., vaccines) and methods for using the immunogenic compositions for inducing an immune response directed specifically against senescent cells for treatment and prophylaxis of age-related diseases and disorders, and other diseases and disorders associated or exacerbated by the presence of senescent cells. The immune response evoked by the immunogenic compositions described herein is specific for one or more senescent cell-associated antigens, particularly including one or more senescent cell-associated antigens (SCAAg) present on the cell surface of the senescent cell (SC). This specific immune response that comprises clearance (i.e., removal, elimination, destruction) of senescent cells may include a humoral or cellular immune response or both a humoral and cellular immune response. The specific immune response may also mediate antibody-dependent cell cytotoxicity (ADCC) or complement dependent cytotoxicity (CDC) or both. The one or more senescent cell-associated antigens that induce a specific immune response may be presented to a subject by administering one or more different immunogenic compositions as described in greater detail herein.

A subject in need of immunization with any one of the immunogenic compositions described herein, in certain embodiments, exhibits features of an age-related phenotype, age-related disorder, or age-sensitive trait. In certain embodiments, the age-related phenotype, age-related disorder, or age-sensitive trait may result from contact with a senescence-inducing stimulus or may result from factors that are presently considered part of the normal aging process. In other certain embodiments, the subject has been exposed to at least one senescence-inducing stimulus, which may include, for example, one or more of a chemical stimulus, an environmental stimulus, a genetic modification, a diet modification, or a combination thereof. In certain specific embodiments, the senescence-inducing stimulus comprises irradiation treatment or treatment with one or more chemotherapeutic agents. In other embodiments, the senescence-inducing stimulus is cigarette smoking or other exposure to tobacco (e.g., secondary exposure to cigarette smoke; smokeless tobacco), high fat or high sugar diet, or other environmental insult.

Immunogenic Compositions

As described in detail herein, methods are provided for evoking (i.e., inducing, stimulating, enhancing, boosting) an immune response specific for a senescent cell and that comprises clearance of the senescent cell by the immune system in a subject by administering to the subject (i.e., immunizing) one or more of the immunogenic compositions described herein. An immunogenic composition may comprise any one of the senescent cell associated antigens described herein, including but not limited to, a polypeptide or protein, or immunogenic fragment thereof; glycoprotein or immunogenic fragment thereof; a nucleic acid encoding the polypeptide, protein, or glycoprotein, or immunogenic fragment thereof; a glycolipid; a senescent cell associated carbohydrate or carbohydrate comprising molecule; and a lipid molecule. An immunogenic composition comprises one or more pharmaceutically acceptable excipients and at least one (i.e., one or more) immunogen which is a senescent cell-associated antigen, or which may be an antigenic fragment of a senescent cell-associated antigen. In a particular embodiment, two or more isolated senescent cell-associated antigens (or antigenic fragment(s) thereof) are included in an immunogenic composition, and in an even more particular embodiment, a fusion polypeptide is provided that comprises the two or more senescent cell-associated antigens (or antigenic fragment of any one or more of the two or more senescent cell-associated antigens). In another embodiment, the fusion polypeptide includes at least one or at least two senescent cell-associated antigens and a co-stimulatory polypeptide (such as by way of non-limiting example, B-7.1, ICAM-1, LFA-3, GM-CSF). In other certain embodiments, the immunogenic composition comprises a polynucleotide that encodes at least one or at least two senescent cell-associated antigens or encodes a fusion polypeptide comprising same; a recombinant expression vector comprising the polynucleotide; or an immune cell or other cell into which a senescent cell-associated antigen or a polynucleotide encoding the senescent cell-associated antigen has been introduced. Also provided herein, are immunogenic compositions that comprise a recombinant expression vector as an immunogen. In certain embodiments, the recombinant expression vector is a viral vector and comprises the polynucleotide that encodes a senescent cell associated antigen or antigenic fragment thereof. In other particular embodiments, the immunogen is a senescent cell membrane preparation, a senescent cell organelle preparation, or an exosome of a cell. Each of these immunogens and immunogenic compositions is described in greater detail herein.

For ease of discussion when describing a composition or immunogen comprising two or more senescent cell-associated antigens, for example, one of the two or more antigens may be called a first senescent cell-associated antigen and another of the two or more antigens may be called a second senescent cell-associated antigen, and another different antigen may be called a third senescent cell-associated antigen, etc. Such description may also be used in describing two or more polynucleotides that may be used as an immunogen.

As described in greater detail herein, immunogenic compositions may further comprise components that enhance an immune response to the one or more SCAAgs. For example, immunogenic compositions may further comprise a pharmaceutically acceptable adjuvant. In other embodiments, an immunogenic composition may also comprise a helper antigen or carrier protein.

Senescent Cell Associated Antigens

Cellular senescence is a stable and essentially permanent arrest of cell proliferation, which is accompanied by extensive changes in gene expression. Many types of cells, both normal cells and tumor cells, undergo senescence in response to stress. As described in the art, the phenotype of a senescence cell, such as the phenotype referred to as senescence associated secretory phenotype (SASP), is typified by secretion of numerous cytokines (e.g., inflammatory cytokines), growth factors, extracellular matrix components (ECM) and ECM-degrading enzymes, and proteases, for example. While proliferative arrest poses a formidable barrier to tumor progression (see, e.g., Campisi, Curr. Opin. Genet. Dev. 21:107-12 (2011); Campisi, Trends Cell Biol. 11:S27-31 (2001); Prieur et al., Curr. Opin. Cell Biol. 20:150-55 (2008)), and molecules secreted by senescent cells can stimulate tissue repair (see, e.g., Adams, Molec. Cell 36:2-14 (2009); Rodier et al., J. Cell Biol. 192:547-56 (2011)), senescent cells also secrete molecules that can cause inflammation (see, e.g., Freund et al., Trends Mol. Med. 16:238-46 (2010); Davalos et al., Cancer Metastasis Rev. 29:273-83 (2010)). Low-level, chronic inflammation is a hallmark of aging tissues, and inflammation is a major cause of, or contributor to, virtually every major age-related pathology, including cancer (Ferrucci et al., 2004, Aging Clin. Exp. Res. 16:240-243; Franceschi et al., 2007 , Mech. Ageing Dev. 128:192-105; Chung et al., 2009, Ageing Res. Rev. 8:18-30; Davalos et al., 2010, Cancer Metastasis Rev. 29:273-283; Freund et al., 2010, Trends Molec. Med. 16:238-248). Thus, senescent cells, which increase with age and at sites of age-related pathology, might stimulate local chronic inflammation and tissue remodeling, thereby fueling both the degenerative diseases of aging as well as age-related cancer.

A senescent cell may exhibit any one or more of the following characteristics. (1) Senescence growth arrest is essentially permanent and cannot be reversed by known physiological stimuli. (2) Senescent cells increase in size, sometimes enlarging more than twofold relative to the size of nonsenescent counterparts. (3) Senescent cells express a senescence-associated β-galactosidase (SA-(3-gal), which partly reflects the increase in lysosomal mass. (4) Most senescent cells express p16INK4a, which is not commonly expressed by quiescent or terminally differentiated cells. (5) Cells that senesce with persistent DDR signaling harbor persistent nuclear foci, termed DNA segments with chromatin alterations reinforcing senescence (DNA-SCARS). These foci contain activated DDR proteins and are distinguishable from transient damage foci. DNA-SCARS include dysfunctional telomeres or telomere dysfunction-induced foci (TIF). (6) Senescent cells express and may secrete molecules associated with senescence, which in certain instances may be observed in the presence of persistent DDR signaling, which in certain instances may be dependent on persistent DDR signaling for their expression. (7) The nuclei of senescent cells lose structural proteins such as Lamin B1 or chromatin-associated proteins such as histones and HMGB1. See, e.g., Freund et al., Mol. Biol. Cell 23:2066-75 (2012); Davalos et al., J. Cell Biol. 201:613-29 (2013); Ivanov et al., J. Cell Biol. DOI: 10.1083/jcb.201212110, page 1-15; published online Jul. 1, 2013; Funayama et al., J. Cell Biol. 175:869-80 (2006)).

The presence of senescent cells can also be determined by detection of senescent cell-associated molecules include growth factors, proteases, cytokines (e.g., inflammatory cytokines), chemokines, cell-related metabolites, reactive oxygen species (e.g., H 2 O 2 ), and other molecules that stimulate inflammation and/or other biological effects or reactions that may promote or exacerbate the underlying disease of the subject. Senescent cell-associated molecules include those that are described in the art as comprising the senescence-associated secretory phenotype (SASP, i.e., which includes secreted factors which may make up the pro-inflammatory phenotype of a senescent cell), senescent-messaging secretome, and DNA damage secretory program (DDSP). These groupings of senescent cell associated molecules, as described in the art, contain molecules in common and are not intended to describe three separate distinct groupings of molecules. Senescent cell-associated molecules include certain expressed and secreted growth factors, proteases, cytokines, and other factors that may have potent autocrine and paracrine activities. Without wishing to be bound by theory, the negative effects of senescent cells are believed to be the result of, at least in part, the secretion of pro-inflammatory cytokines, chemokines, growth factors, and proteases that comprise the SASP of a senescent cell (see, e.g., Coppe et al., PLoS Biol. 6:2853-68 (2008)). Senescent cell-associated molecules that comprise the SASP can disrupt normal tissue structure and function and stimulate malignant phenotypes in pre-malignant or non-aggressive cancer cells (see, e.g., Coppe et al., supra; Coppe et al. J. Biol. Chem. 281:29568-74 (2006); Coppe et al. PLoS One 5:39188 (2010); Krtolica et al. Proc. Natl. Acad. Sci. U.S.A. 98:12072-77 (2001); Parrinello et al., J. Cell Sci. 118:485-96 (2005). ECM associated factors include inflammatory proteins and mediators of ECM remodeling and which are strongly induced in senescent cells (see, e.g., Kuilman et al., Nature Reviews 9:81-94 (2009)). Other senescent cell-associated molecules include extracellular polypeptides (proteins) described collectively as the DNA damage secretory program (DDSP) (see, e.g., Sun et al., Nature Medicine published online 5 Aug. 2012; doi:10.1038/nm.2890).

Senescent cell-associated antigens include molecules that are overexpressed in senescent cells compared to their quiescent or non-senescent counterparts. Certain senescent cell-associated antigens are tissue specific while others are ubiquitously overexpressed in senescent cells. In particular embodiments of the immunogenic compositions described herein, a senescent cell-associated antigen is an antigen present on the cell surface of a senescent cell (e.g., receptor proteins, channel forming proteins, proteins that facilitate diffusion or active transport of molecules and ion across the membrane, cell recognition proteins, and enzymes). These antigens may be present on the cell surface of a cell exclusively or at a greater level on senescent cells compared with non-senescent cells and are therefore useful as immunogens for evoking a specific immune response. Examples of senescent cell-associated antigens include polypeptides and proteins (including glycoproteins), lipids, glycolipids, and carbohydrate molecules that contribute to or are markers of a senescence cell.

Factors considered when selecting a senescent cell-associated antigen include, for example, expression profile, T-cell receptor threading and profiling, pre-existing tolerance, commonality between subjects and cell types as well as the potential to elicit both T-cell and B-cell immunity. Senescent cell-associated antigens can be identified by differential gene expression analysis using, for instance, gene chip profiling to characterize gene products that are either uniquely expressed or overexpressed in SC. The gene products identified from expression profiling are then matched to proteins known to be part of the surfaceome (see, e.g., Bavik et al., Cancer Res . January 15; 66:794-802 (2006)) to generate a subset of surface proteins specifically expressed or overexpressed on the membrane of the senescent cell. Similarly, other molecules that are specific to senescent cells can be used as antigens, such as carbohydrates, glycoproteins, lipids and gangliosides, or proteins with senescence-specific posttranslational modifications. Such molecules can be identified, for instance, by mass spectrometry analysis of fractionated lysates from senescent vs. normal cells.

In one embodiment, an immunogenic composition comprises at least 1 or at least 2, or more isolated senescent cell-associated antigens. In other embodiments an immunogenic composition comprises at least 3, 4, 5, 6, or more senescent cell-associated antigens. Exemplary senescent cell-associated antigens useful as immunogens in the immunogenic compositions described herein include any one or more of the antigens provided in Table 1 (see, e.g., International Patent Application Publication No. WO 2009/085216 (Table 1), which is incorporated herein by reference in its entirety). Other exemplary senescent cell-associated antigens useful as immunogens in the immunogenic compositions described herein include any one or more of the antigens encoded by a polynucleotide that comprises any one of the polynucleotide sequences provided in Table 2 (see also Table 2A that lists the GenBank sequences of Table 2). Non-limiting examples of SCAAgs encoded by a polynucleotide comprising a nucleotide sequence in Table 2 include ADAMTS7, APLP2, ATP6V0D2, BCHE, C11orf87, CD46, CYB5D2, FBXL7, GPR137B, IFI27L1, IL15RA, LAMP2, MYO10, NEU1, NHSL2, NPAS2, OR1F1, PEA15, RAB23, RARB, RNPC3, SELO, SELT, SEMA5B, SERP1, SERPINE1, SLC9A7, SNX3, TBC1D1, TBRG1, TCEANC, TFPI, TNFAIP1, TUBG2, USP18, and ZNF419 (see for example Table 2). Other examples of senescent cell-associated antigens are named in Table 3 and are encoded by the polynucleotides provided in Table 3 (see also, e.g., Sun et al., Nature Medicine published online 5 Aug. 2012; doi:10.1038/nm.2890.)

In a particular embodiment, an immunogenic composition comprises p16INK4a polypeptide, or an antigenic fragment thereof, for use in immunizing a subject. Most senescent cells express the tumor suppressor protein p16INK4a on the cell surface, independent of cell type and senescence inducer (see, e.g., Ohtani et al., J. Med. Invest. 51:146-53 (2004); Campisi et al., Nat. Rev. Med. Cell Biol. 8:729-40 (2007)). Expression of p16INK4a expression is typically undetectable until adulthood and the level of expression increases with age (see, e.g., Zindy et al., Oncogene 15:203-11 (1997)). Moreover, p16INK4a null mice develop and mature normally although they die of cancer in early middle age (see, e.g., Sharpless et al., Nature 413:86-91 (2001)). Without wishing to be bound by theory, p16INK4a peptides may be displayed on the surface of senescent cells in complexes with MHC (major histocompatibility) class 1 molecules.

Evoking an immune response specific for senescent cells that express a SCAAg, such as p16INK4a, wherein the immune response comprises clearance of senescent cells can provide therapeutic benefit. Results from transgenic animal model studies demonstrated that clearance of senescent cells that express p16INK4a delayed acquisition and/or progression of age related diseases (see, e.g., Baker et al., Nature, 479:232-36 (2011); Int'l Patent Application Publication No. WO/2012/177927). Metastasis of tumor cells was significantly inhibited in animals when senescent cells expressing p16INK4a were killed (see, e.g., Int'l Patent Application Publication No. WO 2013/090645).

Immunogenic compositions comprising a p16INK4a polypeptide, or an antigenic fragment thereof, may be prepared using p16INK4a polypeptide derived from a mammal, including but not limited to mouse, rat, or human. Polypeptide sequences for p16INK4a polypeptides from different species are available in public databases, such as GenBank. Amino acid sequences for murine p16INK4a polypeptide are available, for example, at GenBank Nos. AAK83159.1; 158352; and AAA85453.1. Amino acid sequences for human p16INK4a polypeptide are available, for example, at GenBank Nos. P42771.2; NP_000068.1; NP_001182061.1 (see also, e.g., ABC47036.1). Amino acid sequences for rat p16INK4a polypeptide are available, for example, at GenBank Nos. Q9R0Z3.1; NP_113738.1; and AAL76339.1.

An immunogen used in the immunogenic compositions described herein may comprise at least one, or at least two, or at least 3, 4, 5, 6, 7, 8 or more antigenic fragments of a senescent cell-associated antigen. Antigenic fragments may also be referred to herein as immunogenic fragments or antigenic (or immunogenic) peptides. An antigenic fragment of a senescent cell-associated antigen that may be used in the immunogenic compositions described herein comprises an immunogenic portion of a full-length senescent cell-associated antigen, Such antigenic fragments may comprise at least 5, 10, 20, 25, 30, 35, 40, 45, 50, 55, or 60 or more contiguous amino acids (or any number of contiguous amino acids between 5-60, including 5-10, 10-15, 15-20, 20-25, 25-30, 30-35, 35-40, 40-45, 45-50, 40-55, or 55-60, or more than 60 contiguous amino acids) of a senescent cell-associated polypeptide. In a more particular embodiment, an immunogen used in the immunogenic compositions described herein comprises at least 20 contiguous amino acids. An antigenic fragment of a mature or full-length senescent cell-associated antigen has one or more epitopes that induce a specific immune response, which includes production of antibodies that specifically bind to the antigenic peptide and to the immunogenic portion within the mature and full-length polypeptide from which the antigenic peptide is derived, and to a senescent cell that expresses the polypeptide.

The immunogenic compositions contemplated herein also include those with a mixture of full-length senescent cell-associated antigens (with a signal peptide sequence or without all or a portion of a signal peptide sequence) and antigenic fragments of the same or different senescent cell-associated antigens. A polypeptide from which a signal peptide sequence has been cleaved or removed may also be called a mature polypeptide. In certain embodiments, immunogenic compositions comprise immunogen(s) that comprise two or more antigenic fragments of the same senescent cell-associated antigen. In other certain embodiments, the immunogen(s) comprise at least two antigenic fragments wherein each of the at least two antigenic fragments are derived from different senescent cell-associated antigens. The senescent cell-associated antigens described herein and the antigenic fragments thereof may be produced recombinantly by using any one of a variety of molecular biology and protein expression methods and techniques routinely practiced in the art and described herein.

In other certain embodiments, immunogens for use in the methods described herein comprise fusion polypeptides comprising two or more senescent cell-associated antigens or antigenic fragments thereof. The two or more senescent cell-associated antigens or two or more antigenic fragments of the same or different senescent cell-associated antigens may be linked in tandem with or without spacer amino acids between each of the two or more antigenic moieties. The spacer (or linker) may be a single amino acid (such as for example a glycine residue) or may be two, three, four, five, six, seven, eight, nine, or ten amino acids, or may be any number of amino acids between 5 and 100 amino acids, between 5 and 50, 5 and 30, or 5 and 20 amino acids. A polypeptide linker may also include a short peptide linker that may comprise at least two amino acids that are encoded by a nucleotide sequence that is a restriction enzyme recognition site. Examples of such restriction enzyme recognition sites include, for example, BamHI, ClaI, EcoRI, HindIII, KpnI, NcoI, NheI, PmlI, PstI, SalI, and XhoI. The fusion polypeptide may be designed with or without a spacer peptide so long as the two or more antigenic moieties fold properly to maintain antigenic properties of each of the moieties that is observed when each particular antigenic moiety is not present in a fusion polypeptide. If incorporated into a fusion polypeptide, the spacer peptide separates the different antigenic moieties by a distance sufficient to aid or ensure that each properly folds into the secondary and tertiary structures necessary for the desired immunogenic activity.

Surface amino acids in flexible protein regions and which are useful as a linker include glycine (Gly), asparagine (Asn) and serine (Ser). Virtually any permutation of amino acid sequences containing Gly, Asn, and Ser would be expected to satisfy the above criteria for a peptide linker sequence. Other near-neutral amino acids, such as threonine (Thr) and alanine (Ala), may also be used in the linker sequence. Suitable spacer peptides may comprise between from 5 to 100 amino acids and in certain embodiments, comprise between from 5 to 20 amino acids in length. Examples of such linkers include, but are not limited to (Gly 4 Ser (SEQ ID NO:1)), (i.e., Gly-Gly-Gly-Gly-Ser) n ), wherein n=1-12, or n=1-8, or n=1-4; Gly 4 SerGly 5 Ser (SEQ ID NO: 2) (i.e., Gly-Gly-Gly-Gly-Ser-Gly-Gly-Gly-Gly-Gly-Ser); and (Gly 4 SerGly 5 Ser (SEQ ID NO:2)) m (i.e., Gly-Gly-Gly-Gly-Ser-Gly-Gly-Gly-Gly-Gly-Ser) m ) wherein m=2-4.

As described herein, an antigenic fragment comprises at least one immunogenic epitope. In certain embodiments, the number of contiguous amino acid residues in an antigen fragment is sufficient to comprise a conformational epitope that may be formed by non-contiguous portions of a senescent cell associated antigen. Alternatively, a fusion polypeptide may comprise two fragments that each comprise at least 5, 10, 20, 30, 40, or 50 contiguous amino acids of a senescent cell associated antigen and together with or without a spacer moiety properly fold to form a conformational epitope.

In certain instances senescent cells may be used to screen for the presence of senescent cell associated antigens and relevant epitopes for use in preparing antigenic fragments. Such targets can be prepared using random, or selected, synthetic peptide libraries. Alternatively, synthetic peptides of approximately 10-20 amino acids in length may be prepared from an identified senescent cell associated antigen, overlapping by 5-10 residues, which are characterized using any one of a number of immunoassays available in the art. In certain instances, a T cell epitope may be identified by preparing overlapping peptides of between 5-10 contiguous amino acids (e.g., 9 amino acids) of a senescence cell associated antigen. Similarly, B cell epitopes may be identified by preparing overlapping peptides. See, for example, Sturniolo at al., Nature Biotech. 17: 555-61 (1999); Jameson et al., Comput. Appl. Biosci. 4:181-186 (1988); Nakai et al., Trends Biochem. Sci. 24:34-36 (1999); Hopp, Pept. Res. 6:183-90 (1993); Hofmann et al., Biomed. Biochim. Acta 46:855-66 (1987); Menendez et al., Comput. Appl. Biosci. 6:101-105 (1990), which describe methods for identifying antigenic epitopes.

A person skilled in the art would readily appreciate that senescent cell-associated antigens such as p16INK4a, those listed in Table 1, and those encoded by the nucleotide sequences provided in Tables 2 and 3 are exemplary sequences and that variants of each antigen may exist. These variants may have amino acid sequences that are not identical to the exemplary sequences described herein and in the art, yet the variants exhibit the same immunogenicity as the antigens comprising the exemplary sequences (i.e., the immunogenicity is not reduced in a statistically significant, clinically significant, or biologically significant manner). These variants (or species) of individual senescent cell-associated antigens may include amino acid substitutions, deletions, or additions from the exemplary amino acid sequences. A senescent cell-associated antigen species includes antigens that comprise at least 80%, 85%, 90%, 92%, 95%, 97%, 98%, or 99% amino acid sequence identity to the exemplary senescent cell-associated antigen amino acid sequences provided herein, including those in Table 1 and the amino acid sequences encoded by the nucleotide sequences provided in each of Tables 2 and 3, and those described herein for p16INK4a. Percent identity of one amino acid sequence to one or more additional sequences may be determined using any one of the alignment tools described herein and used in the art.

Often a variant will have an amino acid substituted with another amino acid that is included within the same group, such as the group of polar residues, charged residues, hydrophobic residues, and/or small residues, and the like. The effect of any amino acid substitution may be determined empirically merely by testing the resulting modified peptide, polypeptide, or fusion polypeptide for the ability to function in a biological assay, or to bind to a cognate ligand or target molecule, such as a monoclonal or polyclonal antibody.

Senescent cell-associated antigen variants also include those that have amino acid substitutions, deletions or insertions, which may be introduced during chemical synthesis or recombinant production, whichever method is used to produce the particular immunogen. Substitutions, insertions, and deletions of one or more amino acids of the amino acid sequences described herein are those that do not adversely affect or alter (i.e., decrease or reduce in a statistically or biologically significant manner) the immunogenicity of the antigen or antigenic fragment thereof in a statistically, biologically, or clinically significant manner. As described herein, retention of immunogenicity includes the capability to evoke an immune response against a senescent cell, such as production of antibodies that specifically bind to the cognate antigen present on the senescent cell.

In general, an amino acid substitution that may be included in a senescent cell-associated antigen is a conservative substitution. Conservative substitutions of amino acids are well known and may occur naturally or may be introduced when the senescent cell-associated antigen or fusion polypeptide comprising the antigen is recombinantly produced or when the polynucleotide encoding the antigen is produced. A variety of criteria understood by a person skilled in the art indicates whether an amino acid that is substituted at a particular position in an immunogenic peptide or polypeptide is conservative (or similar). For example, a similar amino acid or a conservative amino acid substitution is one in which an amino acid residue is replaced with an amino acid residue having a similar side chain. Similar amino acids may be included in the following categories: amino acids with basic side chains (e.g., lysine, arginine, histidine); amino acids with acidic side chains (e.g., aspartic acid, glutamic acid); amino acids with uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine, histidine); amino acids with nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan); amino acids with beta-branched side chains (e.g., threonine, valine, isoleucine), and amino acids with aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan). Proline, which is considered more difficult to classify, shares properties with amino acids that have aliphatic side chains (e.g., leucine, valine, isoleucine, and alanine). In certain circumstances, substitution of glutamine for glutamic acid or asparagine for aspartic acid may be considered a similar substitution in that glutamine and asparagine are amide derivatives of glutamic acid and aspartic acid, respectively. As understood in the art “similarity” between two polypeptides is determined by comparing the amino acid sequence and conserved amino acid substitutes thereto of the peptide or polypeptide to the sequence of a second peptide or polypeptide, respectively, using any one of the algorithms, such as Align or the BLAST algorithm, or other algorithms described herein and practiced in the art.

Amino acid substitutions, deletions, and additions may be introduced into an a senescent cell associated antigen or antigenic fragment thereof during chemical synthesis of the polynucleotide that encodes the peptide or fusion polypeptide. Alternatively, amino acid substitutions, deletions, and additions may be introduced into an immunogenic peptide or fusion polypeptide recombinantly using well-known and routinely practiced mutagenesis methods (see, e.g., Sambrook et al. Molecular Cloning: A Laboratory Manual, 3d ed., Cold Spring Harbor Laboratory Press, N Y 2001)). Oligonucleotide-directed site-specific (or segment specific) mutagenesis procedures may be employed to provide an altered polynucleotide that has particular codons altered according to the substitution, deletion, or insertion desired. Alternatively, random mutagenesis techniques, such as alanine scanning mutagenesis, error prone polymerase chain reaction mutagenesis, and oligonucleotide-directed mutagenesis may be used to prepare immunogenic peptide and fusion polypeptide variants (see, e.g., Sambrook et al., supra).

Assays for assessing whether a respective senescent cell associated antigen or an antigenic fragment thereof prepared for immunization folds into a conformation comparable to the antigen as expressed by a senescent cell include, for example, the ability of the protein to react with mono- or polyclonal antibodies that are specific for native or unfolded epitopes, the retention of ligand-binding functions, and the sensitivity or resistance of the mutant protein to digestion with proteases (see Sambrook et al., supra). Such variants can be identified, characterized, and/or made according to methods described herein or other methods known in the art, which are routinely practiced by persons skilled in the art.

Polynucleotides and Recombinant Expression Vectors

In certain embodiments, the immunogenic composition useful in a method for inducing an immune response specific for a senescent cell comprises at least one polynucleotide that encodes a senescent cell-associated antigens or antigenic fragment thereof as an immunogen. In certain embodiments, the at least one polynucleotide encodes at least two senescent cell-associated antigens or antigenic fragments thereof. In other embodiments, the immunogen comprises two polynucleotides, wherein each of the two polynucleotides encodes a different senescent cell-associated antigen or antigenic fragment thereof. In a more specific embodiment, a polynucleotide useful in the immunogenic compositions encodes at least or at least two or more senescent cell-associated antigens wherein the polynucleotide(s) comprises a nucleic acid sequence provided in either Table 2 or Table 3. In another embodiment, the polynucleotide of the composition comprises a nucleotide sequence that encodes a senescent cell-associated antigen provided in Table 1. In still another specific embodiment, the polynucleotide of the composition comprises a nucleotide sequence that encodes p16INK4a (including but not limited to murine, rat, non-human primate, and human p16INK4a).

A polynucleotide that is an immunogen may be administered as a “naked polynucleotide” or may be incorporated into a recombinant expression vector that is administered to the subject (see, e.g., Ulmer et al., Science 259:1745-49, 1993 and reviewed by Cohen, Science 259:1691-1692, 1993). Also provided herein are recombinant expression vectors that comprise the polynucleotide that encodes a senescent cell associated antigen or antigenic fragment thereof. To obtain efficient transcription and translation of the immunogen (i.e., the senescent cell-associated antigen or antigenic fragment thereof), the encoding polynucleotide sequences in each vector should include at least one appropriate expression control sequence (also called a regulatory expression sequence or feature) (e.g., promoter, enhancer, leader), which are described in greater detail herein, that is operatively linked to the encoding polynucleotide sequence(s). These recombinant expression vectors are thus provided for expression of the senescent cell-associated antigen or antigenic fragment thereof in any appropriate host cell that has been transformed, transduced, or transfected with a recombinant expression vector. The recombinant expression vector may also include nucleotide sequences that encode a co-stimulatory molecule, which provides transcription and translation of the senescent cell-associated antigen (or fragment thereof) and the co-stimulatory molecule in the same cell.

The recombinant expression vector may be a plasmid DNA or cosmid DNA. Plasmid DNA or cosmid DNA that contains one or more polynucleotides encoding an immunogen as described herein are readily constructed using standard techniques well known in the art. The vector genome may be typically constructed in a plasmid form that can then be transfected into a packaging or producer cell line. The plasmid generally comprises sequences useful for replication of the plasmid in bacteria. Such plasmids are well known in the art. In addition, vectors that include a prokaryotic origin of replication may also include a gene whose expression confers a detectable or selectable marker such as a drug resistance. Typical bacterial drug resistance products are those that confer resistance to ampicillin or tetracycline. For analysis to confirm that the correct nucleotide sequences are incorporated in plasmids, the plasmid may be replicated in E. coli , purified, and analyzed by restriction endonuclease digestion and/or its nucleotide sequence determined by conventional methods.

In other particular embodiments, the recombinant expression vector is a viral vector. Exemplary recombinant expression viral vectors include a lentiviral vector, poxvirus vector, adenovirus vector, adenovirus-associated virus vector, or a herpes virus vector. In other embodiments, the recombinant expression vector is of prokaryotic origin, and includes recombinant bacteria and recombinant expression vectors that are expressed in bacteria.

A number of suitable, available lentiviral genome based vectors are available in the art, including those identified for human gene therapy applications (see, e.g., Pfeifer et al., Annu. Rev. Genomics Hum. Genet. 2:177-211 (2001)). Suitable lentiviral vector genomes include those based on Human Immunodeficiency Virus (HIV-1), HIV-2, feline immunodeficiency virus (FIV), equine infectious anemia virus, Simian Immunodeficiency Virus (SIV) and maedi/visna virus. A desirable characteristic of lentiviruses is that they are able to infect both dividing and non-dividing cells. Safety features of the vector genome are desirably incorporated. Safety features include self-inactivating LTR and a non-integrating genome. See, for example, U.S. Pat. No. 8,273,345 (describing lentiviral vectors for targeted delivery to a dendritic cell); U.S. Patent Application Publication No. 2010/0297168; Simmons et al., Virol. J. 3:8 (2006).

In certain embodiments, a recombinant expression vector is an adenovirus vector. The adenovirus genome is well characterized and the biology of the adenoviruses is known in the art in detail. The adenovirus is not associated with severe human pathology in immunocompetent individuals. Adenovirus particles may be used for efficiently introducing a polynucleotide into a host cell, and the virus is capable of infecting a large variety of cells.

The adenovirus has a double-stranded linear genome with inverted terminal repeats at both ends. During viral replication, the genome is packaged inside a viral capsid to form a virion. The virus enters its target cell through viral attachment followed by internalization (Hitt et al., Advances in Pharmacology 40:137-206, 1997.) Adenovirus vectors may be based on different adenoviruses that are characterized as human or non-human animal or avian serotypes. Examples of non-human animal adenoviruses include bovine, porcine, simian, murine, canine, and avian adenoviruses. Adenoviral vectors can contain regions from a single adenovirus or from two or more adenovirus serotypes.

An adenovirus may be rendered replication defective by deletion of the early-region 1 (E1) of the viral genome. Most adenoviral vectors currently used in gene therapy have a deletion in the E1 region, where genetic information of interest is introduced. Human adenoviruses have been categorized into about six different subgroups that encompass 51 distinct adenovirus serotypes. A serotype is defined on the basis of its immunological distinctiveness determined by quantitative neutralization assays using animal antisera. Simian adenoviral vectors may also be used in the methods described herein for evoking an immune response specific for a SCAAg and that comprises clearance of senescent cells. Adenoviral serotypes that may be used for constructing recombinant expression vectors include human adenoserotypes, for example, Ad1, Ad2, Ad6, Ad5, Ad11, Ad12, Ad24, Ad26, Ad34, Ad35, Ad48, Ad49, and Ad50, and simian adenoserotypes, for example, common chimpanzee adenovirus (Ch) subtypes ChAd55, ChAd73, ChAd83, ChAd146, ChAd147, and ponobo chimpanzee adenovirus (Pan) subtypes, PanAd1, PanAd2, and PanAd3.

Adenoviral vectors include recombinant vectors that are either replication-defective or replication-competent. Replication-defective adenoviral vectors typically lack the E1A gene (required for induction of adenovirus expression and DNA replication) and E1B genes (called E1) and instead contain an expression cassette consisting of a promoter and pre-mRNA processing signals that drive expression of a gene encoding a non-adenoviral polypeptide, such as an immunogen of interest. E3 genes or portions thereof may also be deleted.

Historically, the usefulness of adenovirus as a vehicle for transgene delivery has been limited by induction of neutralizing anti-adenoviral immunity following an initial administration, resulting in shorter-term and reduced levels of transgene expression. Serotype Ad5 vectors, for example, were developed (see, e.g., Chroboczek, et al., J. Virology 186:280-285 (1992)); however, neutralizing antibodies to Ad5 are highly prevalent in humans. More recently, serotype Ad5 vectors have been modified to provide more effective immunization against an antigen of interest delivered by the adenovirus. By way of example, adenoviral vectors that may be used in the methods described herein for inducing an immune response specific for a senescent cell include chimeric Ad5-based constructs in which the hexons from Ad6 is incorporated in place of the Ad5 hexon (see, e.g., Youil, et al., Human Gene Therapy 13(2): 311-320 (2002) doi:10.1089/10430340252769824). Other Ad5/Ad6 adenoviral vectors may be used for expressing a senescent cell associated antigen for inducing an immune response against senescent cells (see, e.g., U.S. Pat. No. 8,142,794 (U.S. Patent Application Publication No. 2009/0233992).

In certain specific embodiments, the adenovirus vector used in the immunogenic compositions described herein is a replication-defective adenovirus and has a serotype that is less likely to have induced pre-existing immunity to the serotype, such as a serotype selected from Ad11, Ad24, Ad26, Ad34, Ad35, Ad48, Ad49, and Ad50. In another particular embodiment, the serotype is Ad11, AD35, or AD49. In a more particular embodiment, the serotype is AD35. In certain embodiments, two or more recombination expression vectors are used as immunogens for expression of two or more senescent cell-associated antigens or two or more two or more antigenic fragments of the same or different senescent cell-associated antigens, and each recombination vector is independently selected from an adenovirus serotype Ad11, Ad24, Ad26, Ad34, Ad35, Ad48, Ad49, and Ad50. Exemplary adenoviral vectors can be prepared according to Crucell AdVac® technology (Crucell, Leiden, The Netherlands). See, for example, U.S. Pat. Nos. 8,221,971; 8,202,723; 8,114,637; 8,052,967; 8,012,467; 7,820,440; 7,781,208; 7,749,493; 7,741,099.

A recombinant adenovirus that at least a deletion in the E1 region to accommodate insertion of genetic information related to expression of the SCAAg(s) of interest may include sequences encoding the E1B-55K gene product that increases the expression of the pIX gene present in the adenovirus and which expresses a non-functional E1B-55K gene product (see, e.g., U.S. Pat. No. 8,052,967). These adenoviruses appear more stable and/or can incorporate more exogenous DNA than the corresponding adenovirus that lacks all E1B-coding sequences. Alternatively, or in addition to, the presence of E1B-55K sequences increasing the expression of the pIX gene, the sequences preceding the pIX-coding sequence may be changed into a stronger promoter, which may be a heterologous promoter, to increase the expression of pIX, resulting in an increase of the stability of a recombinant adenovirus and/or an increase of the packaging capacity of the adenoviral particle produced.

As described herein, exogenous genetic information that encodes one or more SCAAgs of interest can be inserted into the genome where adenoviral E1 sequences have been deleted. In addition to the E1 region deletion, E3 sequences can also be deleted from such adenoviral vectors to increase the capacity for SCAA genetic information. For example, B-type adenovirus serotypes such as Ad34 and Ad35 have a different E3 region than other serotypes, which region is involved in suppressing immune response to adenoviral products.

Adenovirus capsid, in particular the penton and/or the hexon proteins, may induce an immune response to the adenoviral vector. Thus, the adenoviral vector may comprise the elements of at least one capsid protein or functional part thereof, such as fiber, penton and/or hexon proteins or a gene encoding at least one of them from a less immunogenic subtype, such as Ad35. In other certain embodiments, any one of the fiber, penton, and hexon proteins may be encoded by a gene derived from a simian (e.g., chimpanzee) adenovirus. Other deletions and various combinations of part or complete deletions of E2, E3, and E4 regions, combined with the E1 deletion, can be used, if necessary, in combination with a packaging cell comprising the genetic information lacking in the adenoviral vector when necessary for replication of the adenoviral vector. For delivery of the transgene, the adenoviral particle can be targeted specifically to target cells of interest via binding to that specific cell either through capsid-receptor binding or through other means.

Targeting of adenoviruses can be performed in many different ways to deliver the adenoviral vectors to the cells of interest using methods routinely practiced in the art. By way of example, capsid alterations (fiber, hexon and/or penton modifications, such as deletions, swaps between fibers of different serotypes, and additions of peptides and/or other binding moieties), wherein chimeric fibers are produced that recognize a receptor present on the cell of interest or wherein the binding of the penton-base is used. Other possibilities are linking targeting moieties to the capsid proteins wherein, for instance, binding peptides, known and strong binding proteins, or antibodies or parts thereof, are linked to the capsid proteins to achieve specific targeting.

In a particular embodiment, the adenovirus vector is a recombinant adenovirus of adenovirus serotype 35 (Ad35) wherein at least the Ad35 fiber knob has been replaced by the fiber knob of a serotype that binds to the Coxsackievirus and Adenovirus Receptor (CAR). The Ad35 fiber knob may be replaced with the sequence that encodes the fiber knob from serotype Ad5 or the knob, shaft and part of the tail may be replaced. The shaft and tail of the fiber may be of the carrying backbone serotype, such as Ad35, whereas the shaft domain is of the same serotype as fiber knob serotype. When the tail region is derived from the backbone serotype, the interaction of the adenovirus with the remaining part of the capsid will more likely result in production of stable vectors in the art.

In other certain embodiments, a recombinant expression vector is an adenoviral vector that is a simian adenovirus vector (see, e.g., Int'l Patent Application Publication Nos. WO 03/046124; WO 03/000851; WO 2010/085984; WO 2012/089833; U.S. Patent Application Publication Nos. 2011/0129498; 2013/0101618; U.S. Pat. No. 6,083,716). By way of non-limiting example, the adenoviral vector may be derived from a chimpanzee adenovirus, which may be a common chimpanzee adenovirus (ChAd) or a bonobo chimpanzee adenovirus (PanAd). By using a simian adenoviral vector, an adverse effect associated with the preexisting immunity in humans to common serotypes of human adenoviruses can be avoided. The adenovirus types ChAd55, ChAd73, ChAd83, ChAd146, ChAd147, PanAd1, PanAd2, and PanAd3 are characterized by a the absence of preexisting neutralizing antibody in humans directed against these adenovirus types (see, e.g., U.S. Patent Appl. Publ. No. 2011/012949, and references cited therein).

Simian adenoviral vectors may contain one or more of the fiber, hexon, and penton proteins of ChAd55, ChAd73, ChAd83, ChAd146, ChAd147, PanAd1, PanAd2, and/or PanAd3. Fiber, hexon, and penton proteins are adenovirus capsid proteins that represent the most surface exposed adenovirus epitopes. The aforementioned chimpanzee hexon, penton, and fiber protein sequences may also be used to improve other adenoviruses by replacing one or more of these major structural capsid proteins or functional fragments thereof of any adenovirus, such as any of the human adenoviruses described herein and known in the art, which provide recombinant adenoviruses with a reduced seroprevalence in humans.

As with human adenoviral vectors, simian adenoviral vectors are preferably replication defective, meaning that the adenovirus is incapable of replication because it has been engineered to comprise at least a functional deletion or a complete removal of a gene product that is essential for viral replication. For example, and as described herein, one or more genes selected from the group consisting of E1A, E1B, E2A, E2B, E3 and E4 gene can be deleted, rendered non-functional, and/or can be replaced with sequences that includes appropriate expression control sequence(s) operatively linked to the nucleotide sequence encoding one or more SCAAg(s).

In still other embodiments, the recombinant viral vector is an adenovirus-associated virus (AAV) vector. Adeno-associated virus (AAV) is a replication-deficient parvovirus that is able to infect a wide spectrum of cells without inducing any effects on cellular growth, morphology, or differentiation. AAV is non-pathogenic. The AAV genome has been sequenced and well characterized. The single-stranded DNA genome is about 4.7 kb in length and includes 145 nucleotide inverted terminal repeat (ITRs). The ITRs play a role in integration of the AAV DNA into the host cell genome. The remainder of the genome is divided into two essential regions that carry the encapsidation functions: the left-hand part of the genome, which contains the rep gene involved in viral replication and expression of the viral genes; and the right-hand part of the genome, which contains the cap gene encoding the capsid proteins. When AAV infects a host cell, the viral genome integrates into the host's chromosome resulting in latent infection of the cell. In the instances of recombinant AAV vectors having no Rep and/or Cap genes, the AAV can be non-integrating and exists transiently as an episome. AAV depends upon a helper virus (for example, adenovirus or herpesvirus) to provide genes that allow for production of AAV in the infected cell. In the case of adenovirus, genes E1A, E1B, E2A, E4 and VA provide helper functions. Upon infection with a helper virus, the AAV provirus is rescued and amplified, and both AAV and adenovirus are produced. To date, at least 11 serotypes of AAV have been identified and isolated from humans or primates.

AAV vectors are designed such that all viral genes are replaced by an expression cassette for the transgene encoding the polypeptide of interest (e.g., an SCAAg), leaving intact the essential cis elements of the genome, the inverted terminal repeats (ITRs), DNA packaging signal, and the replication origin. Replication and packaging of AAV vectors requires all AAV and Adenovirus/HSV helper functions to be provided in trans. While wild-type AAV is capable of integrating in a site-specific manner into human chromosome 19, site-specific integration of recombinant AAV does not occur to a significant extent because of the lack of Rep protein expression. Onset of transgene expression is generally delayed by 2-4 weeks.

The ability of AAV vectors to infect a broad host range, transduce both dividing and non-dividing cells in vitro and in vivo, and maintain high levels of expression of the transduced genes in the absence of a significant immune response to the transgene product in general have made AAV an attractive vector for recombinant use. AAV vector particles are thought to be non-pathogenic and are heat stable, resistant to solvents, detergents, and changes in pH and temperature. The ITRs have been shown to be the only cis elements required for replication and packaging and may contain some promoter activities. Thus, no viral genes are encoded by AAV vectors.

In another particular embodiment, the recombinant viral vector is a Herpes Simplex vector, such as a Herpes Simplex I (HSV1) or a Herpes Simplex II (HSV2) viral vector. The HSV1 genome has been sequenced and comprises 152 kb encoding at least 80 gene products, about half of which are essential for viral replication. The HSV2 genome has also been sequenced and comprises 155 kb encoding 74 gene products, corresponding closely to the HSV1 genome. The lytic pathway of HSV infection is characterized by the regulated sequential expression of three ordered classes of viral gene products: immediate early (IE or α), early (E or β), and late (L or γ) genes. Upon release of the viral DNA into the host cell nucleus, the viral genome circularizes and expression of five IE genes (infected cell protein ICP4, ICP27, ICP0, ICP22, and ICP47) is induced. V16 binds to an enhancer element present in all IE promoters and activates transcription. The IE genes are involved in transactivation of the E genes, which encode DNA polymerase and other proteins involved in altering the intracellular milieu to favor viral replication. Expression of the L genes follows which mostly encode structural proteins of the capsid, tegument, and envelope. A productive HSV infection results in death of the host cell.

The HSV genome can also be grouped according to whether they are essential or nonessential to viral replication. Essential genes are required to produce new infectious viral particles in permissive cell culture infections. Non-essential, or accessory, genes encode proteins that are not required but are important for optimum lytic replication or affect the life cycle of the virus in vivo (e.g., host range, pathogenesis, latency). In the unique short (US) region of the HSV genome, glycoprotein D is the only essential gene. Large segments of viral sequence in the US region may be replaced with a transgene of interest. The HSV genome may accommodate up to 40-50 kb of exogenous sequence.

Several factors contribute to the interest in HSV based vectors for vaccines. HSV sequences are known and well characterized; HSV elicits strong and durable immune responses by various routes of administration; HSV has a large cargo capacity (>160 kb); the viral DNA persists in the host cell nucleus as an episomal element; HSV genome carries the tk gene which can be exploited to kill infected cells with appropriate drugs (e.g., gangcyclovir). The use of vectors derived from HSV type I and type II is well known in the art and has been previously described (see, e.g., U.S. Pat. No. 6,071,692; U.S. Pat. No. 6,613,892; U.S. Pat. No. 6,838,279; WO2000/077167; WO1990/009441; U.S. Pat. No. 5,846,707; U.S. Pat. No. 5,288,641; WO2005/092374; U.S. Pat. No. 6,613,892; WO2006/004878; and US2011/0171257). Vectors based on HSV type I or type II include: replication-defective viruses; amplicon vectors; and attenuated viruses.

Attenuated, replication-competent viral vectors have mutations or deletions of non-essential genes (see, e.g., Hu and Coffin, 2003, Int. Rev. Neurobiol. 55:165-84; Todo, 2008, Front. Biosci. 13:2060-4; Varghese and Rabkin, 2002, Cancer Gene Ther. 9:967-78; Hunter et al., 1999, J. Virol. 73:6319-6326; US Patent Publication 20080089910). Non-essential HSV genes, such as thymidine kinase, ribonucleotide reductase, virion-host shut off, and ICP34.5, are involved in replication, virulence, and immune evasion and optimize viral growth in host cells. Deletion or modification of non-essential genes may yield HSV mutants with decreased pathogenicity, such as, reduced replication in normal quiescent cells but replication ability in tumor or dividing cells. ICP34.5 deleted HSV, either alone or in combination with deletion of ribonucleotide reductase, replicate selectively in malignant cells (see, e.g., Shah et al., 2003, J. Neurooncol. 65:203-226; Post et al., 2004, Curr. Gene Ther. 4:41-51). HSV has been shown to infect dendritic cells, suggesting that HSV may be used to deliver transgenes to dendritic cells for vaccination (see, e.g., Kruse t al., 2000, J. Virol. 74:7127-7136; Coffin et al., 1998, Gene Ther. 5:718-722; Mikloska et al, 2001, J. Virol. 75:5958-5964). Attenuated HSV vectors for dendritic cells have been previously described (U.S. Pat. No. 6,641,817).

Replication-defective (incompetent) vectors derive from mutant HSV viruses with mutations or deletions in one or more genes essential for the lytic cycle. A transgene may be inserted in the viral genome so that it is packaged into the viral particle along with HSV DNA. Replication defective HSV are grown in complementing cell lines which provide the missing essential gene(s) in trans. Replication-defective vectors, in which one or more of the IE genes (ICP0, ICP4, ICP22, ICP27, and ICP47) are deleted in various combinations, have been constructed (see, e.g., Kaplitt et al., 1997, J. Neurosci. Methods 71:125-132; Krisky et al., 1998, Gene Ther. 5:1593-1603; Krisky et al., Gene Ther. 1997, 4:1120-1125; Wu et al., 1996, J. Virol. 70:6358-6369). Alternatively, HSV mutants with inactivated VP16 may be used to circumvent the use of complementing cell lines expression IE proteins. Inactivation of VP16 to eliminate its IE gene transactivation function in HSV vectors, combined with conditional mutations in ICP4 and ICP0 can express foreign genes without killing the host cell (see, e.g., Preston et al., 1997, Virology 229:228-239). In yet another example, deletion of virion host shutoff protein (VHS) from replication incompetent HSV vectors allows activation of dendritic cells and induction of antigen-specific T cell responses (see, e.g., Samady et al., 2003, J. Virol. 77:3768-3776).

Amplicons are plasmid-derived vectors engineered to contain both the origin of HSV DNA replication (ori) and HSV cleavage/packaging signal (pac). Upon transfection into mammalian cells with HSV helper functions, amplicons are replicated and amplified as head-to-tail linked concatamers, which are then packaged into viral particles. Several advantages of using amplicon vectors for gene delivery include: a large transgene capacity; ability to introduce multiple copies of the transgene per infected cell; ability to infect wide variety of host cells; easy construction; and limited toxicity.

There are several methods known in the art for producing amplicon particles. One prepares amplicon vectors in cells transfected with amplicon plasmid and infected with replication-defective helper HSVs. However, the use of HSV as helper virus may result in helper-contaminated vector stocks, which can induce cytotoxicity and inflammation (see, e.g., Epstein et al., 2005, Curr. Gene Ther. 5:445-458; Zhang et al., 2006, J. Virol. Methods 137:177-183; Sia et al., 2007, J. Virol. Methods 139:166-174). Alternatively, conditional packaging helper viruses using Cre/loxP-based site-specific recombination to remove the packaging signal may be used (Logvinoff and Epstein, 2000, Virology 267:102-110; Zaupa et al., 2003, Human Gene Therapy 14:1049-1063). Yet another option is provide a plasmid comprising the HSV genome, without the packaging signals, e.g., by using pac-deleted overlapping cosmids (see, e.g., Fraefel et al., 1996, J. Virol. 70:7190-7197) or a pac-deleted and ICP27-deleted BAC-HSV-1 (see, e.g., Saeki et al., 2001 , Mol. Ther. 3:591-601).

In other certain embodiments, the immunogenic composition useful in a method for inducing an immune response specific for a senescent cell comprises a bacterial delivery system that comprises a recombinant bacterium into which a recombinant expression vector has been introduced. In a certain particular embodiment, the recombinant bacterium is a recombinant Listeria bacterium, which may be attenuated (see, e.g., Bower et al., Proc. Natl. Acad. Sci. USA 103:5102-107 (2006); Chamekh, Immunopharmacology and Immunotoxicology 32:1-4 (2010); U.S. Pat. Nos. 7,695,725; 7,833,775; 7,927,606; 7,935,804; 8,287,883; 8,580,939). Listeria has been used to stimulate cellular immunity because of its intracellular life cycle. After the bacteria infect the host, the bacteria are taken up by phagocytes into a phagolysosomal compartment. The majority of the bacteria are subsequently degraded, and peptides of the antigen of interest are presented as MHC II-peptide complexes. The recombinant expression vector introduced into the bacteria, such as Listeria , comprises a nucleotide sequence that encodes at least one appropriate bacterial expression control sequence (e.g., promoter, enhancer, leader) that is operatively linked to the encoding polynucleotide sequence(s) for a senescence cell-associated antigen(s). The polynucleotide sequence encoding the senescence cell-associated antigen (SCAAg) may also comprise a signal peptide sequence (e.g., a bacterial signal peptide) fused in frame to the amino terminal end of the SCAAg. In other embodiments, the polynucleotide encodes the SCAAg fused in frame with a polypeptide that enhances expression and processing of the SCAAg. In one embodiment, the SCAAg is fused in frame with an autolysin. The autolysin polypeptide has been shown useful for efficient expression and secretion of a heterologous antigen in Listeria (see, e.g., U.S. Pat. No. 7,842,289).

Recombinant expression viral vectors may be incorporated into a vector particle that comprises a recombinant expression system that comprises one recombinant expression vector (also called a first recombinant expression vector) comprising a polynucleotide sequence encoding at least one senescent cell-associated antigen or antigenic fragment thereof and a second recombinant expression vector that includes a polynucleotide sequence that encodes a second senescent cell-associated antigen or antigenic fragment thereof. Alternatively the second recombinant expression vector may encode a co-stimulatory molecule.

In certain embodiments, the recombinant expression vectors or viral particles are engineered to be delivered to a target cell using methods and techniques known to and practiced by persons skilled in the art. In particular embodiments, the target cell is an immune cell that is an antigen-presenting cell, such as a dendritic cell. Such methods comprise contacting (i.e., permitting interaction) of the target cell with a vehicle that delivers the polynucleotide.

In yet another embodiment, recombinant viral vectors are recombinant viruses that are senolytic and are replication competent or conditionally replication competent. Virus replication leads to amplification, killing of the senescent cell, and introduction of the progeny virus into other senescent cells. Because of the inherent cytotoxicity and efficiency with which viruses can infect other cells, recombinant viruses may be prepared that exhibit a high enough degree of senescent cell selectivity, and hence safety, for treatment of a subject in need of removal of senescent cells to treat or prevent a disease or disorder. The viruses are constructions so that the viruses are attenuated in normal cells but retain their ability to kill senescent cells. Such engineering may include modifying the ability of viruses to bind to, or replicate in senescent cells, while others have involved the construction of replication-competent viruses encoding suicide proteins. The SCAAgs described herein may be used to target senescent cells replication competent or conditionally replication competent viruses.

The SCAAgs described herein are useful for identifying ligands, including antibodies, of the respective SCAAg, which may be used for targeting a lytic virus to senescent cells. By way of example, SCAAg as described herein may be used to prepare an antibody that specifically binds to the SCAAg. Antigen binding fragments (e.g., Fv, sFv, one or more CDRs with one or more adjacent framework regions) of the antibody may be prepared either synthetically or recombinantly according to methods routinely practiced in the art. Mutant viral vectors may be prepared in which the viral vector comprises on its surface a viral surface protein (or portion thereof) that is fused in frame with an antigen binding fragment that specifically binds to a SCAAg, such as a senescent cell surface polypeptide, to target the viral vector to a senescent cell. In other embodiments, the viral surface protein is fused in frame with a ligand, or a senescent cell binding peptide of the ligand, of a SCAAg. Senolytic viruses include by way of non-limiting example, HSV, lentiviruses, pox viruses, adenoviruses, rhabdoviruses, measles viruses, Newcastle Disease Virus (NDV), rhabdoviruses (e.g., vesicular stomatitis virus), reovirus, and Seneca Valley viruses. See, e.g., Dalba et al., Mol Ther. 2007 March; 15(3):457-66. Epub 2007 Jan. 23; U.S. Pat. Nos. 5,585,096; 5,728,379; 7,501,126; 7,749,745; Doronin et al., J. Virol. 74:6147-55 (2000); Sarkar et al., Cell Cycle 2006 July; 5(14):1531-6. Epub 2006 Jul. 17; Lorence et al. (eds): Replication-Competent Viruses for Cancer Therapy. Monogr Virol. Basel, Karger, 2001, vol 22, pp 160-182 (DOI: 10.1159/000061724); Int'l Appl. Publ. No. WO 2002/053760).

Conditionally replication competent senolytic viruses also include those from which at least one regulatory element for expression of an essential viral gene is replaced with a regulatory element, such as a p16 promoter, to ensure that the virus replicates and subsequently kills only senescent cells (see, e.g., Int'l Appl. Publ. No. WO 2013/158664). A viral surface protein of such a virus may be fused in frame with an antigen binding fragment that specifically binds to a SCAAg or fused in frame with a ligand, or peptide thereof, of the SCAAg for binding specifically to a senescent cell.

In yet another embodiment, a virus such as rhabdovirus, may be engineered to target and kill senescent cells and also express an immunostimulatory molecule that promotes removal of the virus by the immune system (see, e.g., Batenchuk et al., Blood Cancer Journal (2013) 3, e123; doi:10.1038/bcj.2013.23; Published online 12 Jul. 2013). Without wishing to be bound by theory, the destruction of the senescent cells evokes an immune response to senescent cell associated antigens that promotes continued clearance of senescent cells.

Exosomes, Senescent Cell Membranes, Senescent Cell Lysates

In certain embodiments, the immunogenic composition for evoking an immune response specific for a senescent cell in a subject is an exosome comprising at least one senescent cell-associated antigen or antigenic fragment thereof. Exosomes are nanovesicles of endosomal origin that are secreted in the extracellular environment following fusion of late endosomal multivesicular bodies with the plasma membrane (see, e.g., Garin et al., 2001, J. Cell Biol. 152:165-80). Cells from various tissue types have been shown to secrete exosomes, including dendritic cells, immune cells (e.g., B-cells and T cells), tumor cells, mast cells, and senescent cells. Exosomes from different cell types exhibit discrete sets of proteins and lipid moieties that reflect their cells of origin (see, e.g., Thery et al., 1999, 147:599-610; Thery et al., 2001, J. Immunol. 166:7309-18). Exosomes display proteins involved in antigen presentation (MHC Class I and MHC Class II) (Iero et al., 2008, Cell Death Differ. 15:80-88). Their main protein markers are tetraspanins (CD63, CD9), Alix, and TSG101, and they are able to mediate immune response by activating T cells (via antigen presentation); natural killer cells (via NKG2D ligand binding); and dendritic cells (via antigen transfer) (see, e.g., Thery et al., 2009, Nat. Rev. Immunol. 9:581-593). Though their precise biological function and mechanism have yet to be determined and without wishing to be bound by theory, exosomes are thought to be involved in cell-cell communication, leading to immune modulation. By way of example, exosomes from dendritic cells pulsed with peptides derived from tumor antigens elicit anti-tumor immune responses in an animal model having the matching tumor (see, e.g., Wolfers et al., 2001, Nat. Med. 7:297-303; Zitvogel et al., 1998, Nat. Med. 4:594-600). Accordingly, exosomes based immunotherapy may be useful as a cell-free vaccine (see, e.g., Viaud et al., 2010, Cancer Res. 70:1281-5; Tan et al., 2010, Intl. J. Nanomed. 5:889-900).

Exosome producing cells may be any cell, preferably of mammalian origin, that produces and secretes membrane vesicles of endosomal origin by fusion of late endosomal multivesicular bodies with the plasma membrane. Endosomal producing cells include, for example, dendritic cells, B cells, tumor cells, senescent cells, T cells, and mast cells. In one embodiment, exosome-producing cells are mammalian senescent cells, mammalian T cells, and mammalian dendritic cells, typically murine (useful for preclinical studies) or human. Dendritic cell exosomes are capable of activating T cells and NK cells. In certain embodiments, exosomes may be obtained from any autologous subject-derived cells, heterologous haplotype-matched cells, or heterologous stem cells to reduce or avoid the generation of an immune response in a subject to whom the exosomes are administered. For evoking production of antibody(ies), B cells may be used as exosome producing cells because the resulting exosomes comprise accessory functions and molecules such as MHC Class II molecules that facilitate antibody production. Additionally, B cell exosomes are able to bind follicular dendritic cells, which is a feature of antibody induction. Exosomes from other cells types, such as non-antigen presenting cells, for example, senescent cells, can spread antigens or peptide-loaded MHC complexes to antigen presenting cells for more efficient presentation. Recombinant exosomes comprising recombinant MHC molecules have also been described (see, e.g., WO00/028001, incorporated herein in its entirety). In some embodiments, exosomes originating from one or more cell types may be used as an immunogen for evoking an immune response specific for a senescent cell.

One or more senescent cell-associated antigens or antigenic fragments thereof may be selected for loading of exosome producing cells. If the exosome producing cell is a senescent cell, it is naturally loaded with senescent-cell associated antigens or antigenic fragments thereof. An exosome producing senescent cell may also be modified with specific recombinant senescent cell-associated antigens or antigenic fragments thereof, co-stimulatory molecules, targeting moieties, or loaded with an exogenous antigen (i.e., a helper antigen or carrier protein) to enhance the immune response. A variety of methods known in the art may be used to load antigen presenting cells with antigens, including peptide pulsing (see, e.g., Macatonia et al., 1989, J. Exp. Med. 169:1255; Takahashi et al., 1993, Int. Immunol. 5:849), antigen pulsing (see, e.g., Inaba et al., 1990, J. Exp. Med. 172:631; Hsu et al., 1996, Nat. Med. 2:52); placing cells in contact with one or more antigenic protein complexes; placing cells in contact with cells or membranes of cells expressing antigens or antigenic peptides (“direct transfer”) (see, e.g., Zou et al., Cancer Immunol. Immunother. 15:1); placing cells in contact with membrane vesicles containing antigens or antigenic peptides (e.g., exosomes from senescent cells) (see, e.g., U.S. Pat. No. 6,685,911); placing cells in contact with liposomes containing antigens or antigenic peptides (see, e.g., Nair et al., 1992, J. Exp. Med. 175:609); placing cells in contact with polynucleotides encoding antigens or antigenic peptides (optionally incorporated in vectors of plasmid, viral, or chemical type) (see, e.g., Boczkowsky et al., 1996, J. Exp. Med. 184:465-472; Bhardwaj et al., 1994, J. Clin. Invest. 94:797; Alijagie et al., 1995, Eur. J. Immunol. 25:3100). Methods of producing , purifying, or using exosomes for therapeutic purposes or as research tools are known in the art and have been described, for example, in U.S. Pat. No. 6,685,911; U.S. Pat. No. 7,625,573; PCT Publication Nos. WO99/03499; WO00/44389; WO00/028001; and WO97/05900, each of which is incorporated by reference herein in its entirety.

Exosomes produced by the exosome-producing cell may be collected and/or purified using techniques known in the art, such as differential centrifugation, chromatography, etc. (see, e.g., Thery et al., 1999, Cell Biol. 147:500-10; Lehmann et al., 2008, Cancer Res. 68:7864; U.S. Patent Publication No. 2004/0241176; U.S. Pat. No. 6,899,863; PCT Publication No. WO 2000/44389; each of which is incorporated herein by reference in its entirety). Methods for targeting expression of recombinant polypeptides to exosomes using exosome-specific targeting domains (e.g., C1 and/or C2 domains from lactadherin) have been described in U.S. Pat. No. 7,704,964 and Rountree et al., 2011, Cancer Res. 71:5235, each reference incorporated herein in its entirety. Such methods may be used to deliver chimeric senescent cell-associated antigens to exosomes if they are not naturally expressed in senescent cell exosomes. Exosome producing cells may also be modified such that exosomes include a targeting moiety on the surface. The exosomes may be targeted to a selected tissue or cell type (see, e.g., PCT Publication No. WO 2010/119256, incorporated herein in its entirety).

In certain embodiments of the present disclosure, senescent cell exosomes comprising one or more senescent-cell associated antigens may be modified to lack one or more immunosuppressive polypeptides normally found in the exosome. Such modifications may be useful for senescent cell exosomes. While cancer cells have been shown to release exosomes, cancer cell exosomes may circumvent immunosurveillance and recognition of the tumor by the immune system via inclusion of immunosuppressive polypeptides (e.g., Fas, programmed death ligand-1, programmed death ligand-2) in the cancer cell exosome (see, e.g., U.S. Patent Publication No. 2010/0092524; Iero et al., supra). Likewise, senescent cell exosomes may circumvent immunosurveillance and recognition of senescent cells by the immune system via inclusion of immunosuppressive polypeptides. Expression of immunosuppressive polypeptides may be inhibited using methods known in the art, such as siRNA, antisense, and modifications thereto (see, e.g., U.S. Patent Publication No. 2010/0092524, incorporated herein by reference in its entirety).

In certain embodiments, the immunogenicity of senescent cell exosomes may be enhanced by expressing exogenous antigens (e.g., superantigens) on the cell surface as described in U.S. Patent Publication No. 2010/0092524, incorporated herein in its entirety. Superantigens can bind directly to MHC complex without being processed. Examples of superantigens that may be incorporated into senescent cell exosomes as exogenous polypeptides include Staphylococcal enterotoxins (SEs, e.g., Staphylococcal enterotoxin A or Staphylococcal enterotoxin E); a Streptococcus pyogenes exotoxin (SPE), a Staphylococcus aureus toxic shock syndrome toxin (TSST-1); a Streptococcal mitogenic exotoxin (SME); and a Streptococcal superantigen (SSA).

In other embodiments, an immunogen used in the immunogenic compositions and methods described herein comprises a senescent cell membrane preparation. In a particular embodiment, the senescent cell preparation comprises the cell membrane (also called the plasma cell membrane or cytoplasmic cell membrane), thereby providing senescent cell associated antigens present on the cell surface of the senescent cell. Senescent cell associated antigens present on the cell membrane may include proteins and glycoproteins that are channel forming proteins, proteins that facilitate diffusion or active transport of molecules and ion across the membrane, cell recognition proteins, receptor proteins, and enzymes. In another embodiment, an organelle of a senescent cell may be an immunogen. For example, an organelle that is involved in processing, production, or transport of a cell surface molecule, for example, in certain instances, a lysozome, endoplasmic reticulum, Golgi apparatus, or an endosome, may be prepared from senescent cells. Senescent cell membranes and cell organelles may be prepared using methods known and practiced by the skilled person (see, e.g., Current Protocols in Cell Biology , John Wiley & Sons, 2009).

Dendritic Cell Immunogens (Vaccines)

In certain embodiments, the present disclosure provides methods of evoking an immune response specific for a senescent cell in a subject using an immunogen comprising antigen-presenting cells (APCs), e.g., dendritic cells (DCs), that include senescent cell-associated antigens, for example, by being presented on the surface of the antigen-presenting cells.

Dendritic cells play a critical role in coordinating innate and adaptive immune responses. DCs are bone-marrow derived cells characterized by dendritic morphology and high mobility that are seeded in all tissues. DCs are specialized antigen presenting cells that are capable of capturing and processing antigens, migrating from the periphery to a lymphoid organ, and presenting the antigens in a MHC-restricted manner to naive T-cells (see, e.g., Banchereau & Steinman, 1998, Nature 392:245-252; Steinman et al., 2003 , Ann. Rev. Immunol. 21:685-711). Immature DCs are capable of processing and presenting antigens, which leads to immune regulation and/or suppression. Maturation (activation) of DCs is required to induce differentiation of antigen-specific T cells into effector T cells (see, e.g., Palucka et al., 2012, Nat. Rev. Cancer 12:265-277). Mature DCs express high levels of MHC-antigen complex and other co-stimulatory molecules, such as CD40, B7-1, B7-2, and CD1a (see, e.g., Steinman, 1991 , Ann. Rev. Immunol. 9:271-296; Banchereau & Steinman, 1998, Nature 392:245-252). These molecules play key roles in stimulating T cells. Due to their properties, DC-based vaccination strategies have been developed in cancer (see, e.g., Heiser et al., 2001, Cancer Res. 61:338; Heiser et al., 2001, J. Immunol. 166:2953; Milazzo et al., 2002, Blood 101:977; Zu et al., 2003, Cancer Res. 63:2127). Likewise, DC based immunogens (vaccines) may be able to elicit CD8 + T cells capable of recognizing peptide-MHC Class complexes on senescent cells and target them for destruction.

Dendritic cells may be obtained from various sources using methods known in the art. DC precursors may be purified from peripheral blood (see, e.g., Fong et al., 2003, Annu Rev. Immunol. 15:138). DCs may be also be differentiated from peripheral blood monocytes or CD34 + hematopoietic progenitor cells ex vivo (see, e.g., Sallusto et al., 1994, J. Exp. Med. 179:1109; Banchereau et al., 2001, Cancer Res. 61:6451; Makensen et al., 2000, Int. J. Cancer 86:385). Methods for in vitro proliferation of dendritic cells from DC precursors and their use as immunogens are described in U.S. Pat. Nos. 5,851,756; 5,994,126; 6,475,483; and 8,283,163 each of which is incorporated herein by reference in its entirety. A method for isolating DCs from human peripheral blood is described in U.S. Pat. No. 5,643,786, incorporated herein by reference in its entirety. U.S. Patent Publication 2006/0063255, U.S. Patent Publication 2006/0057129, and U.S. Pat. No. 7,247,480, each of which is incorporated herein by reference in its entirety, describe methods for making dendritic cell vaccines from human embryonic stem cells.

Methods of isolating APCs, such as dendritic cells, are known in the art. Procedures such as repetitive density gradient separation, fluorescence activated cell sorting techniques, positive selection, negative selection, or a combination thereof are routinely used to obtain enriched populations of DCs. Methods for isolating DCs may be found in O'Doherty et al., 1993, J. Exp. Med. 178:1067-78; Young and Steinman, 1990, J. Exp. Med. 171:1315-32; Freudenthal et al., 1990 , Proc. Natl. Acad. Sci. USA 57:7698-7702; Markowicz and Engleman, 1990, J. Clin. Invest. 85:955-961; Mehta-Damani et al, 1994, J. Immunol. 153:996-1003; Thomas et al., 1993, J. Immunol. 151:6840-6852.

Dendritic cells may be loaded with specific antigens ex vivo and then administered to a subject (see, e.g., Banchereau et al., 2005, Nat. Rev. Immunol. 5:296-306; Figdor et al., 2004, Nat. Med. 10:475-480, each of which is incorporated herein by reference in its entirety). Various methods for loading antigens to DCs have been described and are known in the art. RNA encoding a specific antigen may be pulsed into dendritic cells before administration to a subject by electroporation, cationic lipids, cationic peptides or using dendrimers (see, e.g., Boczkwoski et al. 1996, J. Exp. Med. 184:465; Heiser et al., 2001, Cancer Res. 61:338; Heiser et al., J. Immunol. 2001, 166:2953; U.S. Patent Publication 2006/0063255; Choi et al., 2005, Cell Cycle 4:669). DCs may also be loaded with protein or peptide that is purified or isolated from a target cell, chemically synthesized, or recombinantly expressed. Nucleic acid vectors encoding a specific antigen may also be used for DC loading (see, e.g., Frolkis et al., 2003, Cancer Gene Ther. 10:239). Exemplary vectors include plasmids, cationic lipid complexes, viral vectors, cDNA encoding antigen loaded onto dendrimers, or other small particulates that enhance uptake by phagocytic cells. U.S. Pat. No. 6,300,090 and U.S. Pat. No. 6,455,299 describe using non-replicating viral vectors comprising sequence encoding an antigen for infecting dendritic cells, resulting in antigen presentation on the DC surface.

Alternatively, DCs may be loaded with specific antigens in vivo. Antigens may be delivered directly to DCs using chimeric proteins that are comprised of a DC receptor-specific antibody fused to a selected antigen (see, e.g., Bonifaz et al., 2004, J. Exp. Med. 199:815-824; Bonifaz et al., 2004, J. Exp. Med. 196:1627-1638; Hawiger et al., 2001, J. Exp. Med. 194:769-780; each of which is incorporated herein by reference in its entirety). U.S. Patent Publication 2012/0070462, incorporated herein by reference in its entirety, describes targeted antigen delivery to dendritic cells using recombinant viral vectors comprising a polynucleotide encoding the antigen and a targeting molecule, which binds to a DC-specific surface marker (e.g., DC-SIGN).

In another variation on antigen loading, DCs may be fused with whole senescent cells to express a broad array of senescent cell-associated antigens. Dendritic cell fusion vaccines are known in the art and have been described in Rosenblatt et al., 2005, Expert Opin. Biol. Ther. 5:703-15; Rosenblatt et al., 2011, Blood 117:393-402; Gong et al., Proc. Natl. Acad. Sci. USA 97:2715-2718; Gong et al., 1997, Nat. Med. 3:558-561; U.S. Patent Publication 2004/0115224; U.S. Patent Publication 2005/0238627; and U.S. Patent Publication 2010/0278873, each of which is incorporated herein by reference its entirety.

Antigenic peptides useful for presentation by DCs for vaccination are peptides that stimulate a T cell mediated immune response (e.g., cytotoxic T cell response) by presentation to T cells on MHC molecules. Useful antigenic peptides and proteins for use in the present disclosure include those derived from senescent cells (e.g., senescent cell-associated antigens). Depending on the method of DC loading utilized, a senescent cell-associated antigen may be presented in a variety of forms. In some embodiments, a senescent cell-associated antigen is presented as a senescent cell lysate to DCs. In other embodiments, senescent cell-associated antigens are obtained by acid elution of peptides presented on MHC molecules of the senescent cell surface. For example, senescent cells are washed with an isotonic solution to remove media components. The cells are then treated with acid to dissociate peptides from surface MHCs, and the cells are removed from the solution containing the soluble peptides. Antigenic peptides may be obtained by chemical synthesis or produced using recombinant methods with host cells and vector expression systems. A senescent cell associated antigen may also be delivered as a polynucleotides (RNA or DNA) to a DC directly or indirectly (e.g., via a plasmid or viral vector). The antigenic peptides presented on MHC molecules are typically short peptides and may be 5, 6, 7, 8, 9, or 10 amino acids, for example.

A senescent cell associated antigen introduced into DCs may also be designed as a fusion peptide, wherein the antigen is joined to a protein or peptide sequence that enhances transport into endosomal and other intracellular compartments involved in Class II histocompatibility loading. For example, the N-terminus of such a fusion protein may comprise a suitable heterologous leader or signal sequence for the endosomal compartment and the C-terminus may comprise a transmembrane and luminal component of a member of the LAMP family for lysosomal targeting (see, e.g., U.S. Pat. No. 5,633,234; WO 02/080851; Sawada et al., 1993 , J. Biol. Chem. 268:9014; each of which is incorporated by reference herein in its entirety). Endosomal and lysosomal sorting signals include tyrosine based signals, dileucine-based signals, acidic clusters, and transmembrane proteins labeled with ubiquitin (see, e.g., Bonifacino et al., 2003, Annu. Rev. Biochem. 72:395; U.S. Pat. No. 6,248,565).

Characterization of Immunogens

The immunogenicity of isolated senescent cell associated antigens, antigenic fragments, and fusion polypeptides, exosomes, cell membrane and organelle preparations, dendritic cell immunogens, and the products encoded by the polynucleotides described herein may be determined by using any one or more immunogenicity, immunochemistry, and/or cellular immune response assays, and non-human animal models routinely practiced in the art and described herein. For characterizing the immunogens described herein, use of polyclonal and/or monoclonal antibodies may be desired. The antibody may be obtained from or derived from an animal, for example, fowl (e.g., chicken) and mammals, which include but are not limited to a mouse, rat, hamster, rabbit, or other rodent, a cow, horse, sheep, goat, camel, human, or other primate. Polyclonal antisera are obtained from an animal by immunizing the animal with an immunogenic composition described herein.

Immunogenic compositions and SCAAgs may also be characterized in pre-clinical studies that evaluate the safety of the immunogenic composition to be administered to a subject. Ultimately, the safety and efficacy of immunogenic compositions will be determined by clinical studies, which are monitored by regulatory agencies.

Characterizing the immunogenic activity of an immunogen described herein may also be determined in art-accepted animal models. The capability of the immunogen to effectively induce an immune response in a subject can also be assessed in an animal model for the particular disease, disorder, or condition that is being treated or prevented by immunization. The immunogenicity of any one of the immunogens described herein may be determined by administering the immunogenic composition comprising the immunogen to a host (or subject, patient) according to immunization protocols described herein and in the art. Typically, after administering an initial dose of the immunogenic composition (also called the primary immunization) to a host, one, two or more doses of the immunogenic composition (also called boosting or booster doses) are administered.

To evaluate the immunogenicity of any one of the immunogenic compositions described herein, the immunogen may be administered to an animal by a parenteral (e.g., intravenous), intraperitoneal, intramuscular, intradermal, intraocular, or subcutaneous route. The immunogenic composition may further comprise a suitable adjuvant to enhance the immune response to the immunogen. See, e.g., Harlow et al., Antibodies: A Laboratory Manual , Cold Spring Harbor Laboratory (1988). Adjuvants typically used for immunization of non-human animals include but are not limited to Freund's complete adjuvant, Freund's incomplete adjuvant, montanide ISA, Ribi Adjuvant System (RAS) (GlaxoSmithKline, Hamilton, Mont.), and nitrocellulose-adsorbed antigen. In general, after the first injection, animals receive one or more booster immunizations according to a preferred schedule that may vary according to, inter alia, the immunogen, the adjuvant (if any) and/or the particular animal species. The B cell immune response may be monitored by periodically bleeding the animal, separating the sera from the collected blood, and analyzing the sera in an immunoassay, such as an ELISA or Ouchterlony diffusion assay, or the like, to determine the specific antibody titer. When an adequate antibody titer is established, the animals may be bled periodically to accumulate the polyclonal antisera.

In general, to monitor the immune response of an immunized host during pre-clinical studies in animals, sera is obtained from the animals prior to the first dose (i.e., pre-immune sera) and obtained after the final boosting dose. Sera may also be obtained after any one or more of the boosting doses between the primary dose and final boosting dose. To monitor the immune response of an immunized host during clinical studies or during post-marketing studies, sera may also be obtained from humans before the first immunization and after one or more administrations of the immunogenic compositions.

Production of senescent cell associated antigen-specific antibodies in an immunized host (including a human host) may include production of any class of immunoglobulin, including IgG, IgA, IgM, and/or IgE, and isotypes within the classes. The presence of specific IgG, IgM, IgE, and IgA may be detected in a biological sample (e.g., serum, nasal wash, lung lavage, or other tissues) obtained from an immunized host. For detection of antibodies in an immunoassay, the biological sample may be permitted to interact with or contact an antigen that is purified, isolated, partially isolated, or a fragment thereof, or to interact with or contact a senescent cell, which may be fixed (such as with ethanol or formaldehyde) or unfixed or non-denatured.

The immunogenicity of immunogens described herein may also be characterized by any number of assays and techniques practiced in the art, including immunoassays to evaluate binding and the capability of the immunogen to induce an immune response. By way of non-limiting example, immunoassays include ELISA, immunoblot, radioimmunoassay, immunohistochemistry, fluorescence activated cell sorting (FACS), Ouchterlony, and the like. Conditions for in vitro assays include temperature, buffers (including salts, cations, media), and other components that maintain the integrity of any cell used in the assay and the compound, which a person skilled in the art will be familiar and/or which can be readily determined. A person skilled in the art also readily appreciates that appropriate controls can be designed and included when performing the in vitro methods and in vivo methods described herein.

In vitro assay methods typically comprise contacting the biological sample with at least one source of the antigens described above and herein (particularly, e.g., an isolated senescence cell associated antigen or fragment thereof, a senescent cell or a lysate, membrane preparation or exosome comprising the antigen of interest) under conditions and for a time sufficient for an antibody in the sample to interact with the antigen source (i.e., mixing, combining, or in some manner permitting the biological sample and the antigen to interact). An antibody present in the biological sample that specifically binds to the antigen can be detected using any one of the exemplary detection methods described herein and in the art for detecting antibody-antigen binding. By way of non-limiting example, antibody bound to the antigen may be detected using a reagent specific for a conserved region of the antibody, such as the Fc portion of the antibody, which reagent is typically selected depending on the source of the antibody (i.e., whether the antibody is from an animal, such as a mouse, rat, goat, or sheep, etc. or whether the antibody is from a human). Such reagents typically comprise a detectable label, for example an enzyme, fluorescent label, luminescent label, or radioactive label. Additional exemplary reagents include those that detect a specific isotype or class of antibody. Many such reagents may be obtained from commercial sources.

Whether an immune response includes the capability to kill or clear senescent cells may be determined according to techniques and methods described herein and practiced in the art. An immune response that comprises selectively clearing a senescent cell or facilitating selective clearance of a senescent cell kills, removes, destroys, reduces viability, or decreases survival of a senescent cell (i.e., in some manner reduces the quantity of viable senescent cells in the animal or in the cell-based assay) in a statistically significant or biologically significant manner when compared with the immune response to kill, remove, clear, reduce viability, or decrease survival of a non-senescent cell. Such an immune response may therefore be useful for treating or preventing an age-related disease or disorder or another disease associated with or exacerbated by the presence of senescent cells. Transgenic animal models as described herein and in the art may be used to determine clearance of senescent cells (see, e.g., Baker et al., supra; Nature, 479:232-36 (2011); Int'l Patent Application Publication No. WO/2012/177927; Int'l Patent Application Publication No. WO 2013/090645). The transgenic animals by determining the level of a detectable label or labels that is expressed in senescent cells of the animal. Exemplary transgenic animal models contain a transgene that includes a nucleic acid that allows for controlled clearance of senescence cells (e.g., p16 ink4a positive senescent cells). The transgene also nucleotide sequences includes a detectable label, for example, one or more of a red fluorescent protein; a green fluorescent protein; and one or more luciferases to detect clearance of senescent cells.

Senescent cells and senescent cell associated molecules can be detected by techniques and procedures described in the art. For example, the presence of senescent cells in tissues can be analyzed by histochemistry or immunohistochemistry techniques that detect the senescence marker, SA-beta gal (SA-Bgal) (see, e.g., Dimri et al., Proc. Natl. Acad. Sci. USA 92: 9363-9367 (1995). The presence of the senescent cell-associated polypeptide p16 can be determined by any one of numerous immunochemistry methods practiced in the art, such as immunoblotting analysis. Expression of p16 mRNA in a cell can be measured by a variety of techniques practiced in the art including quantitative PCR. The presence and level of senescence cell associated polypeptides (e.g., polypeptides of the SASP) can be determined by using automated and high throughput assays, such as an automated Luminex array assay described in the art (see, e.g., Coppe et al., PLoS Biol 6: 2853-68 (2008)).

The presence of senescent cells can also be determined by detection of senescent cell-associated molecules include growth factors, proteases, cytokines (e.g., inflammatory cytokines), chemokines, cell-related metabolites, reactive oxygen species (e.g., H 2 O 2 ), and other molecules that stimulate inflammation and/or other biological effects or reactions that may promote or exacerbate the underlying disease of the subject. Senescent cell-associated molecules include those that are described in the art as comprising the senescence-associated secretory phenotype (SASP, i.e., which includes secreted factors which may make up the pro-inflammatory phenotype of a senescent cell), senescent-messaging secretome, and DNA damage secretory program (DDSP). These groupings of senescent cell associated molecules, as described in the art, contain molecules in common and are not intended to describe three separate distinct groupings of molecules. Senescent cell-associated molecules include certain expressed and secreted growth factors, proteases, cytokines, and other factors that may have potent autocrine and paracrine activities. (see, e.g., Coppe et al., supra; Coppe et al. J. Biol. Chem. 281:29568-74 (2006); Coppe et al. PLoS One 5:39188 (2010); Krtolica et al. Proc. Natl. Acad. Sci. U.S.A. 98:12072-77 (2001); Parrinello et al., J. Cell Sci. 118:485-96 (2005). ECM associated factors include inflammatory proteins and mediators of ECM remodeling and which are strongly induced in senescent cells (see, e.g., Kuilman et al., Nature Reviews 9:81-94 (2009)). Other senescent cell-associated molecules include extracellular polypeptides (proteins) described collectively as the DNA damage secretory program (DDSP) (see, e.g., Sun et al., Nature Medicine published online 5 Aug. 2012; doi:10.1038/nm.2890).

Determining the effectiveness of an immune response to clear senescent cells as described herein in an animal model is typically performed using one or more statistical analyses with which a skilled person will be familiar. By way of example, statistical analyses such as two-way analysis of variance (ANOVA) may be used for determining the statistical significance of differences between animal groups treated with an agent and those that are not treated with the agent (i.e., negative control group). Statistical packages such as SPSS, MINITAB, SAS, Statistika, Graphpad, GLIM, Genstat, and BMDP are readily available and routinely used by a person skilled in the animal art.

Conditions for a particular assay including temperature, buffers (including salts, cations, media), and other components, which maintain the integrity of the antibodies within the pre-immune and immune sera and the integrity of the antigen (which may be an immunogenic peptide, dimeric peptide, or fusion polypeptide, M protein, Spa protein, or bacteria) used in the assay, are familiar to a person skilled in the art and/or which can be readily determined. A biological sample, such as serum, is contacted (mixed, combined with, or in some manner permitted to interaction) with the antigen, under conditions and for a time sufficient to permit interaction between the antigen and antibodies present in the sample. The interaction, or level of binding, of the antigen to an antibody present in an immune serum sample (or other biological sample) may be determined and compared to a level of binding of the respective antigen to antibodies present in a pre-immune sample (or an otherwise suitable negative control). An increase in the level of binding of the antigen to the immune serum sample compared with the pre-immune serum sample indicates that the immunogenic composition evoked production of specific antibodies. As noted herein, the level of binding of an immunogen to antibodies present in a sample from an immunized host is typically referred to in the art as the titer.

Adjuvants and Helper Antigens

The immunogenic compositions described herein may also comprise a suitable adjuvant. An adjuvant is intended to enhance (or improve, augment) the immune response to the immunogens described herein, including antigenic fragments and fusion polypeptides comprising the fragments (i.e., increase the level of the specific immune response in a statistically, biologically, or clinically significant manner compared with the level of the specific immune response in the absence of administering the adjuvant).

For administration in humans, a pharmaceutically acceptable adjuvant is one that has been approved or is approvable for human administration by pertinent regulatory bodies. For example, as discussed herein and known in the art, Complete Freund's adjuvant is not suitable for human administration. Desired adjuvants augment the response to the immunogen without causing conformational changes in the immunogen that might adversely affect the qualitative immune response. Suitable adjuvants include aluminum salts, such as alum (potassium aluminum sulfate), or other aluminum containing adjuvants such as aluminum hydroxide, aluminum phosphate, or aluminum sulfate. Other pharmaceutically suitable adjuvants include nontoxic lipid A-related adjuvants such as, by way of non-limiting example, nontoxic monophosphoryl lipid A (see, e.g., Persing et al., Trends Microbiol. 10:s32-s37 (2002)), for example, 3 De-O-acylated monophosphoryl lipid A (MPL) (see, e.g., United Kingdom Patent Application No. GB 2220211). Other useful adjuvants include QS21 and QuilA that comprise a triterpene glycoside or saponin isolated from the bark of the Quillaja saponaria Molina tree found in South America (see, e.g., Kensil et al., in Vaccine Design: The Subunit and Adjuvant Approach (eds. Powell and Newman, Plenum Press, N Y, 1995); U.S. Pat. No. 5,057,540). Other suitable adjuvants include oil in water emulsions, optionally in combination with immune stimulants, such as monophosphoryl lipid A (see, e.g., Stoute et al., N. Engl. J. Med. 336, 86-91 (1997)). Other suitable adjuvants include polymeric or monomeric amino acids such as polyglutamic acid or polylysine, liposomes, and CpG (see, e.g., Klinman, Int. Rev. Immunol. 25(3-4):135-54 (2006); U.S. Pat. No. 7,402,572; European Patent No. 772 619). CpG is often an adjuvant of choice when administering a polynucleotide that encodes a senescent cell associate antigen or antigenic fragment thereof (or a vector comprising the polynucleotide).

In another embodiment, the immunogenicity of an immunogen described herein may be enhanced by combining the immunogen with a helper antigen or carrier moiety. A helper antigen includes a T cell helper antigen, which is an antigen that is recognized by a T helper cell and evokes an immune response in a T helper cell. T helper cells are lymphocytes that are involved in activating and directing other immune cells such as cytotoxic T cells, B cells, and/or macrophages. Carrier moieties have been long known in the immunology art and include without limitation, keyhole limpet hemocyanin, bovine serum albumin, cationized BSA, or ovalbumin. For human use, toxoids of bacterial proteins (e.g., tetanus toxoid, diphtheria toxoid, cholera toxoid, and the like) are typically employed as carrier proteins.

In certain embodiments, the immunogen comprises at least one senescent cell associated antigen or at least one antigenic fragment thereof and a helper antigen or carrier moiety that is linked, conjugated, or attached to the antigen or antigenic fragment thereof. The helper antigen or carrier moiety may be recombinantly expressed in frame and directly linked to a senescent cell associated antigen or fragment thereof. In certain embodiments, a fusion protein comprising at least two senescent cell associated antigens or at least two antigenic fragments thereof or a combination of same may also comprise a helper antigen or carrier moiety. Alternatively, the helper antigen or carrier moiety may be chemically conjugated, linked, or attached to the senescent cell associated antigen or fragment thereof. In still another embodiment, the helper antigen or carrier moiety may be formulated together with any immunogen described herein but not covalently or non-covalently bound to the immunogen to form an immunogenic composition.

Co-Stimulatory Molecules

In another embodiment, the immunogenic compositions described herein (including those described above and immunogenic compositions comprising a recombinant antibody described below), include a co-stimulatory polypeptide. In certain embodiments, the immunogen comprises at least one senescent cell associated antigen or at least one antigenic fragment thereof and a co-stimulatory molecule that is linked, conjugated, or attached to the antigen or antigenic fragment thereof. The co-stimulatory molecule may be recombinantly expressed in frame and directly linked to a senescent cell associated antigen or fragment thereof. In certain embodiments, a fusion protein comprising at least two senescent cell associated antigen or at least two antigenic fragments thereof or a combination of same may also comprise a co-stimulatory molecule. Alternatively, the co-stimulatory molecule may be chemically conjugated, linked, or attached to the senescent cell associated antigen or fragment thereof. In still another embodiment, the co-stimulatory molecule may be formulated together with any immunogen described herein but not covalently or non-covalently bound to the immunogen to form the immunogenic composition.

Exemplary co-stimulatory molecules include, by way of example, GM-CSF, IL-2, IL-4, IL-6, IL-7, IL-15, IL-21, IL-23, TNFα, B7.1 (CD80), B7.2 (CD86), 41BB, CD40 ligand (CD40L), drug-inducible CD40 (iCD40), and the like. When an immunogenic composition comprises a polynucleotide encoding the co-stimulatory molecule, or a recombinant expression virus comprising the polynucleotide, expression of the co-stimulatory molecule is typically under the control of one or more regulatory elements selected to direct the expression of the coding sequences in a cell of choice, such as a dendritic cell.

Recombinantly engineered antigen-presenting cells such as dendritic cells, for example, may be modified by recombinant technology to express increased levels of antigen presenting machinery, adhesion and/or co-stimulatory molecules, including MHC class I/antigen complexes, MHC class II/antigen complexes, CD1, hsp70-90, CD9, CD63, CD81, CD11b, CD11c, CD40, CD54 (ICAM-1), CD63, CD80, CD86, 41BBL, OX40L, chemokine receptor CCR1-10 and CXCR1-6, mannose-rich C-type lectin receptor DEC205 and Toll-like receptors TLR4 and TLR9 or membrane-bound TGF-β. The exosomes derived from these recombinantly engineered antigen presenting cells will express these additional molecules and can transfer them to the T helper cells, T regulatory cells, or dendritic cells upon absorption.

Processes for Preparing Senescent Cell Associated Antigens, Fragments, and Polynucleotides

Peptides and polypeptides may be chemically synthesized by manual techniques or by automated procedures. By way of example, solid phase polypeptide synthesis has been performed since the early 1960's. Numerous improvements to synthesis methods have been developed, and many methods have been automated and chemistries have been developed to protect the terminal ends and other reactive groups (see, e.g., Geysen et al., J. Immun. Meth. 102:259-274 (1987); Miranda et al., Proc. Natl. Acad. Sci. USA 96:1181-86 (1999); Frank et al., Tetrahedron 44:6031-6040 (1988); Hyrup et al., Bioorg. Med. Chem. 4:5-23 (1996); Perry-O'Keefe et al., Proc. Natl. Acad. Sci. USA 93:14670-675 (1996); Schnolzer, et al. Int. J. Pept. Protein Res. 40, 180-193 (1992); Hackeng et al., Proc. Natl. Acad. Sci. USA 94:7845-50 (1997); Creighton, T. E. Protein: Structures and Molecular Properties, pp. 55-60, W. H. Freeman and Co., New York, N.Y. (1984)). Equipment for automated synthesis of polypeptides is commercially available and may be operated according to the manufacturer's instructions. Synthesized peptides, polypeptides, and fusion polypeptides may also be obtained from any number of different custom peptide synthesizing manufacturers. If required, synthesized peptides or polypeptides may be purified using preparative reverse phase chromatography, affinity chromatography partition chromatography, gel filtration, gel electrophoresis, or ion-exchange chromatography or other methods used in the art.

Polynucleotides may also be chemically synthesized or may be constructed by recombinant methods familiar to a person skilled in the art. Polynucleotides can also be synthesized using an automatic synthesizer. The nucleotide sequence can be designed with the appropriate codons for the particular amino acid sequence desired. In general, preferred codons may be selected for the intended host in which the nucleotide sequence will be expressed. One recombinant method of preparing a polynucleotide includes assembly from overlapping oligonucleotides prepared by standard methods to provide a complete coding sequence (see, e.g., Au et al., Biochem. Biophys. Res. Commun. 248:200-203 (1998); Stemmer et al., Gene 164:49-53 (1995); Ausubel et al. (eds.), Current Protocols in Molecular Biology , (Greene Publ. Assoc. Inc. & John Wiley & Sons, Inc., 1993)); Sambrook et al., et al. Molecular Cloning: A Laboratory Manual, 3rd Ed., (Cold Spring Harbor Laboratory 2001; and elsewhere). Methods for purifying polynucleotides after either chemical synthesis or recombinant synthesis are known to persons skilled in the art (see, e.g., Ausubel et al., supra; Sambrook et al., supra).

Chemical synthesis of oligonucleotides for primers and probes has long been practiced in the art. Improved methods for synthesizing oligonucleotides and polynucleotides, which provide more rapid results, greater yields, and longer polynucleotides, have since been developed and automated (see, e.g., Gao et al., Biopolymers 73:579-96 (2004); Mueller et al., Chem. Biol. 16:337-47 (2009); Lee et al., Nucleic Acids Res. 38:2514-21 (2010)). Polynucleotides that encode the senescent cell-associated antigen, antigenic fragments thereof, and fusion polypeptides described herein may be synthesized commercially (see, e.g., GENSCRIPT, Piscataway, N.J.).

Polynucleotides that encode a senescent cell-associated antigen, antigenic fragment thereof, or fusion polypeptide described herein may be recombinantly expressed in a variety of different host cells. Host cells containing recombinant expression constructs may be genetically engineered (transduced, transformed, or transfected) with the vectors and/or expression constructs (for example, a cloning vector, a shuttle vector, or an expression construct). The vector or construct may be in the form of a plasmid, a viral particle, a phage, etc. The engineered host cells can be cultured in conventional nutrient media modified as appropriate for activating promoters, selecting transformants, or amplifying particular genes or encoding-nucleotide sequences. Selection and maintenance of culture conditions for particular host cells, such as temperature, pH and the like, will be readily apparent to the ordinarily skilled artisan. In general, the desired host cell is one that can be adapted to sustained propagation in culture to yield a stable cell line that can express sufficient amount of the desired peptide, polypeptide, or fusion protein. In certain embodiments, the cell line is an immortal cell line, which refers to a cell line that can be repeatedly passaged (at least ten times while remaining viable) in culture following log-phase growth. In other embodiments the host cell used to generate a cell line is a cell that is capable of unregulated growth, such as a cancer cell, or a transformed cell, or a malignant cell.

Useful bacterial expression constructs are prepared by inserting into an expression vector a structural DNA sequence encoding the desired peptide, polypeptide, or fusion protein together with suitable translation initiation and termination signals in an operative reading phase with a functional promoter. The construct may comprise one or more phenotypic selectable markers and an origin of replication to ensure maintenance of the vector construct and, if desirable, to provide amplification within the host. Suitable prokaryotic hosts for transformation include E. coli, Bacillus subtilis, Salmonella typhimurium and various species within the genera Pseudomonas, Streptomyces , and Staphylococcus , although others may also be employed as a matter of choice. Any other plasmid or vector may be used as long as the plasmid or vector is replicable and viable in the host. Thus, for example, the polynucleotides as provided herein may be included in any one of a variety of expression vector constructs as a recombinant expression construct for expressing the senescent cell-associated antigen, antigenic fragment thereof, or fusion polypeptide. Such vectors and constructs include chromosomal, nonchromosomal, and synthetic DNA sequences, e.g., bacterial plasmids; phage DNA; baculovirus; yeast plasmids; vectors derived from combinations of plasmids and phage DNA; viral DNA, such as vaccinia, adenovirus, fowl pox virus, and pseudorabies.

The appropriate DNA sequence(s) may be inserted into the vector by a variety of procedures with which the skilled person is familiar. In certain instances, the DNA sequence is inserted into an appropriate restriction endonuclease site(s) by procedures known in the art. Omission of restriction sites and the amino acid sequence encoded by the restriction site is contemplated herein and is intended to remove the possibility that a desired immunogenic epitope will be adversely altered or that an epitope will be inadvertently added that may have an undesirable immunogenicity. Standard techniques for cloning, DNA isolation, amplification and purification, for enzymatic reactions involving DNA ligase, DNA polymerase, restriction endonucleases and the like, and various separation techniques are those known and commonly employed by those skilled in the art. Numerous standard techniques are described, for example, in Ausubel et al. ( Current Protocols in Molecular Biology (Greene Publ. Assoc. Inc. & John Wiley & Sons, Inc., 1993)) and in Sambrook et al. ( Molecular Cloning: A Laboratory Manual, 3rd Ed., (Cold Spring Harbor Laboratory 2001)).

The DNA sequence encoding a peptide, polypeptide, or fusion polypeptide in the expression vector is operatively linked to at least one appropriate expression control sequences (e.g., a promoter or a regulated promoter) to direct mRNA synthesis. Representative examples of such expression control sequences include LTR or SV40 promoter, E. coli lac or trp, the phage lambda P L promoter, and other promoters known to control expression of genes in prokaryotic or eukaryotic cells or their viruses. Promoter regions can be selected from any desired gene using CAT (chloramphenicol transferase) vectors or other vectors with selectable markers. Particular bacterial promoters include lad, lacZ, T3, T5, T7, gpt, lambda P R , P L , and trp. Eukaryotic promoters include CMV immediate early, HSV thymidine kinase, early and late SV40, LTRs from retroviruses, and mouse metallothionein-I. Selection of the appropriate vector and promoter and preparation of certain recombinant expression constructs comprising at least one promoter or regulated promoter operatively linked to a polynucleotide described herein is well within the level of ordinary skill in the art.

Design and selection of inducible, regulated promoters and/or tightly regulated promoters are known in the art and will depend on the particular host cell and expression system. The pBAD Expression System (Invitrogen Life Technologies, Carlsbad, Calif.) is an example of a tightly regulated expression system that uses the E. coli arabinose operon (P BAD or P ARA ) (see Guzman et al., J. Bacteriology 177:4121-30 (1995); Smith et al., J. Biol. Chem. 253:6931-33 (1978); Hirsh et al., Cell 11:545-50 (1977)), which controls the arabinose metabolic pathway. A variety of vectors employing this system are commercially available. Other examples of tightly regulated promoter-driven expression systems include PET Expression Systems (see U.S. Pat. No. 4,952,496) available from Stratagene (La Jolla, Calif.) or tet-regulated expression systems (Gossen et al., Proc. Natl. Acad. Sci. USA 89:5547-51 (1992); Gossen et al., Science 268:1766-69 (1995)). The pLP-TRE2 Acceptor Vector (BD Biosciences Clontech, Palo Alto, Calif.) is designed for use with CLONTECH's Creator™ Cloning Kits to rapidly generate a tetracycline-regulated expression construct for tightly controlled, inducible expression of a gene of interest using the site-specific Cre-lox recombination system (see, e.g., Sauer, Methods 14:381-92 (1998); Furth, J. Mamm. Gland Biol. Neoplas. 2:373 (1997)), which may also be employed for host cell immortalization (see, e.g., Cascio, Artif. Organs 25:529 (2001)).

Processes for producing a senescent cell-associated antigen in a host cell comprising a recombinant expression encoding the antigen may be scaled to manufacture large amounts. In another embodiment, a method of manufacture of the immunogenic compositions described herein is provided. Methods of manufacture comprise combining or mixing together the desired senescent cell-associated antigen, antigenic fragment thereof, or fusion polypeptides, polynucleotides, recombinant expression vectors, senescent cell membrane preparation, a senescent cell organelle preparation, exosome of the senescent cell, modified dendritic cell, or recombinant antibody to provide the immunogenic compositions described herein. The methods of manufacture may further comprise combining or mixing one or more physiologically suitable (or pharmaceutically suitable) excipients as described herein. The methods may further comprise combining or mixing the immunogenic composition comprising the desired immunogen with a pharmaceutically suitable adjuvant. At least one pharmaceutically suitable excipient may also be combined or mixed with the immunogenic composition comprising an adjuvant. In still further embodiments, a method of manufacture comprises chemical synthesis or recombinant production of the desired peptides, polypeptides, or fusion polypeptides. Chemical synthesis and recombinant production of the senescent cell-associated antigen, antigenic fragment thereof, and fusion polypeptides are described in detail herein. During manufacture of each immunogen, appropriate manufactures processes (such as Good Manufacturing Practices (GMP)) as required by a regulatory agency are employed. In addition, persons skilled in the art are familiar with techniques and steps to be taken for maintaining stability and integrity of the peptides or fusion polypeptides during manufacture of an immunogenic composition.

A process is provided herein for producing an immunogenic composition (or vaccine) that comprises at least one senescent cell-associated antigen. Into a first host cell a recombinant expression vector is introduced (transfected, transduced, transformed) wherein the vector comprising at least one regulatory expression sequence operatively linked to a nucleotide sequence that encodes a first senescent cell-associated antigen, or an antigenic fragment thereof. If the immunogenic composition will comprise a second senescent cell-associated antigen, a second host cell is transfected, transduced, transformed with a second recombinant expression vector comprising at least one regulatory expression sequence operatively linked to a nucleotide sequence that encodes a second senescent cell-associated antigen, or an antigenic fragment thereof. Each host cell is separately cultured in a medium for a time sufficient and under conditions appropriate for maximizing production of the antigen. Such conditions, which can readily be determined by a person skilled in the art, include maintaining the proper temperature, nutrient level, carbon dioxide level, cell density, atmospheric pressure, and removing waste in a timely manner. The respective antigens are then isolated from the host cell culture. Typically, the cells are harvested (i.e., separated) from the culture by methods practiced in the art such as centrifugation or filtration or a combination thereof. If the antigen is secreted by the host cell, the cell culture medium (also called spent medium) may be concentrated, followed by isolation of the antigen by any one of a number of isolation methods, including any number of chromatography methods and gel electrophoresis. Alternatively, if the antigen is not secreted by the host cell, the cells may be fractionated or lysed or the antigen may form inclusion bodies in the cell, which inclusion bodies are then isolated according to techniques known in the art. Once the senescent cell associated antigen is isolated, it may be formulated with one or more pharmaceutically acceptable excipients. If the immunogenic composition comprises more than one senescent cell associated antigen or fragment thereof, each antigen may be formulated separately with an excipient or the two antigens may be formulated together in the same vessel with a pharmaceutically acceptable excipient.

Passive Immunization—Recombinant Antibodies

Also provided herein are polyclonal and monoclonal antibodies that specifically bind to a senescent cell associated antigen for use in passive immunotherapeutic methods. An antibody that specifically binds to a senescent cell associated antigen (or antigenic fragment thereof, or fusion protein comprising same, or a senescent cell expressing the antigen) may belong to any immunoglobulin class, for example IgG, IgE, IgM, IgD, or IgA. The antibody may be obtained from or derived from an animal, for example, fowl (e.g., chicken) and mammals, which include but are not limited to a mouse, rat, hamster, rabbit, or other rodent, a cow, horse, sheep, goat, camel, human or other primate. The antibody may be an internalising antibody. The antibody may be a monoclonal antibody, which includes a monoclonal antibody derived from any human or non-human animal, a chimeric antibody, humanized antibody, or an antigen-binding fragment thereof.

In a particular embodiment, a recombinant antibody that specifically binds to a senescent cell-associated antigen of interest is provided. The recombinant antibody comprises at least one immunoglobulin variable region domain that specifically binds to a senescent cell-associated antigen. In certain embodiments, the recombinant antibody further comprises a modified human Fc region that exhibits enhanced affinity for an Fcγ receptor. In one embodiment the senescent cell-associated antigen is selected from Table 1 provided below. In certain other embodiments, the senescent cell-associated antigen is encoded by a nucleic acid sequence selected from Table 2 or Table 3. In another specific embodiment, the senescent cell-associated antigen is p16INK4a, for example, murine, human, or rat p16INK4a.

A recombinant antibody as described herein comprises at least one variable region domain. The at least one immunoglobulin variable region domain may comprise either the heavy chain variable region. The variable region domain may be of any size or amino acid composition and will generally comprise at least one hypervariable amino acid sequence responsible for antigen binding and which is adjacent to or in frame with one or more framework sequences. In general terms, the variable (V) region domain may be any suitable arrangement of immunoglobulin heavy (V H ) and/or light (V L ) chain variable domains. In other embodiments, the recombinant antibodies described herein comprise (1) an Fv fragment consisting of the variable regions of both the heavy and light chains, (2) recombinant single chain polypeptide molecules in which light and heavy variable regions are connected by a peptide linker (scFv proteins); or (3) minimal recognition units consisting of the amino acid residues that mimic the hypervariable region. An Fv region is defined in the immunoglobulin art as the N-terminal portion of an Fab fragment of the immunoglobulin and includes the V H (variable heavy chain) and V L (variable light chain) regions that are bound together by non-covalent interactions. Each V H comprises three complementarity determining regions (CDRs; heavy chain CDR1, CDR2, and CDR3) and each V L comprises three CDRs (light chain CDR1, CDR2, and CDR3). Thus, for example, the V region domain may be monomeric and be a V H or V L domain, which is capable of independently binding antigen with acceptable affinity. Alternatively, the V region domain may be dimeric and contain V H -V H , V H -V L , or V L -V L , dimers. Preferably, the V region dimer comprises at least one V H and at least one V L chain that are non-covalently associated (hereinafter referred to as F v ). If desired, the chains may be covalently coupled either directly, for example via a disulfide bond between the two variable domains, or through a linker, for example a peptide linker, to form a single chain Fv (scF v ).

An immunoglobulin variable region may be derived from a monoclonal antibody or polyclonal antibody that specifically binds to a senescent cell associated antigen. Monoclonal and polyclonal antibodies may generally be prepared by any of a variety of techniques known to persons having ordinary skill in the art. See, e.g., Harlow et al., Antibodies: A Laboratory Manual , Cold Spring Harbor Laboratory (1988); Peterson, ILAR J. 46:314-19 (2005)); Green et al., “Production of Polyclonal Antisera,” in Immunochemical Protocols (Manson, ed.), pages 1-5 (Humana Press 1992); Harlow et al., Antibodies: A Laboratory Manual , Cold Spring Harbor Laboratory (1988); Williams et al., “Expression of foreign proteins in E. coli using plasmid vectors and purification of specific polyclonal antibodies,” in DNA Cloning 2 : Expression Systems, 2nd Edition, Glover et al. (eds.), page 15 (Oxford University Press 1995)). Suitable animals include, for example, rabbits, sheep, goats, pigs, cattle, subhuman primates and may also include smaller mammalian species, such as mice, rats, and hamsters, or other species (see, e.g., International Patent Application Publication No. WO 91/11465 (1991) and in Losman et al., Int. J. Cancer 46:310, 1990). Monoclonal antibodies that specifically bind to the senescent cell associated antigen of interest and hybridomas, which are examples of immortal eukaryotic cell lines, that produce monoclonal antibodies having the desired binding specificity, may be prepared, for example, using the technique of Kohler and Milstein ( Nature, 256:495-97 (1976), Eur. J. Immunol. 6:511-19 (1975)) and improvements thereto (see, e.g., Coligan et al. (eds.), Current Protocols in Immunology, 1:2.5.1-2.6.7 (John Wiley & Sons 1991); U.S. Pat. Nos. 4,902,614, 4,543,439, and 4,411,993 ; Monoclonal Antibodies, Hybridomas: A New Dimension in Biological Analyses , Plenum Press, Kennett et al. (eds.) (1980); and Antibodies: A Laboratory Manual , Harlow and Lane (eds.), Cold Spring Harbor Laboratory Press (1988); see also, e.g., Brand et al., Planta Med. 70:986-92 (2004); Pasqualini et al., Proc. Natl. Acad. Sci. USA 101:257-59 (2004)).

An antibody that specifically binds to the senescent cell associated antigen of interest may be derived from a human monoclonal antibody. Human monoclonal antibodies may be generated by any number of techniques with which those having ordinary skill in the art will be familiar. Such methods include, but are not limited to, Epstein Barr Virus (EBV) transformation of human peripheral blood cells (e.g., containing B lymphocytes) (see, e.g., U.S. Pat. No. 4,464,456; see also, e.g., Glasky et al., Hybridoma 8:377-89 (1989)); in vitro immunization of human B cells (see, e.g., Boerner et al., J. Immunol. 147:86-95 (1991)); fusion of spleen cells from immunized transgenic mice carrying inserted human immunoglobulin genes (see, e.g., Green et al., Nature Genet. 7:13 (1994); Lonberg et al., Nature 368:856 (1994); Taylor et al., Int. Immun. 6:579 (1994); U.S. Pat. No. 5,877,397; Bruggemann et al., Curr. Opin. Biotechnol. 8:455-58 (1997); Jakobovits et al., Ann. N. Y. Acad. Sci. 764:525-35 (1995)); isolation from human immunoglobulin V region phage libraries; cloning the light chain and heavy chain variable regions from a B cell that is producing an anti-cellular polypeptide antibody (WO 92/02551; U.S. Pat. No. 5,627,052; Babcook et al., Proc. Natl. Acad. Sci. USA 93:7843-48 (1996)); or other procedures as known in the art and based on the disclosure herein.

The Fv region may further comprise one or all of the framework regions that comprise the variable region of an immunoglobulin. If the Fv region is derived from a non-human antibody, and framework regions are included in the recombinant antibody, the antibody may be further genetically engineered to create a “humanized” antibody. Such a humanized antibody may comprise a plurality of CDRs derived from an immunoglobulin of a non-human mammalian species, at least one human variable framework region. Useful strategies for designing humanized antibodies include, by way of illustration and not limitation, identification of human variable framework regions that are most homologous to the non-human framework regions of the chimeric antibody (see, e.g., Jones et al., Nature 321:522-25 (1986); Riechmann et al., Nature 332:323-27 (1988)). Designing a humanized variable region may include determining CDR loop conformations and structural determinants of the non-human variable regions, for example, by computer modeling, and then comparing the CDR loops and determinants to known human CDR loop structures and determinants (see, e.g., Padlan et al., FASEB 9:133-39 (1995); Chothia et al., Nature, 342:377-83 (1989)). Computer modeling may also be used to compare human structural templates selected by sequence homology with the non-human variable regions (see, e.g., Bajorath et al., Ther. Immunol. 2:95-103 (1995); EP-0578515-A3; Davies et al., Ann. Rev. Biochem. 59:439-73, (1990)). If humanization of the non-human CDRs results in a decrease in binding affinity, computer modeling may aid in identifying specific amino acid residues that could be changed by site-directed or other mutagenesis techniques to partially, completely, or supra-optimally (i.e., increase to a level greater than that of the non-humanized antibody) restore affinity. Those having ordinary skill in the art are familiar with these techniques and will readily appreciate numerous variations and modifications to such design strategies.

A minimal recognition unit is an antibody fragment comprising a single complementarity-determining region (CDR). Such CDR peptides can be obtained by constructing polynucleotides that encode the CDR of an antibody of interest according to methods practiced by persons of ordinary skill in the art (see, for example, Larrick et al., Methods: A Companion to Methods in Enzymology 2:106, (1991); Courtenay-Luck, “Genetic Manipulation of Monoclonal Antibodies,” in Monoclonal Antibodies: Production, Engineering and Clinical Application , Ritter et al. (eds.), page 166 (Cambridge University Press 1995); and Ward et al., “Genetic Manipulation and Expression of Antibodies,” in Monoclonal Antibodies: Principles and Applications, Birch et al., (eds.), page 137 (Wiley-Liss, Inc. 1995)). Alternatively, such CDR peptides and other antibody fragment can be synthesized using an automated peptide synthesizer.

In other embodiments, a minimal recognition unit may be identified from a peptide library. Such peptides may be identified and isolated from combinatorial libraries (see, e.g., International Patent Application Nos. PCT/US91/08694 and PCT/US91/04666) and from phage display peptide libraries (see, e.g., Scott et al., Science 249:386 (1990); Devlin et al., Science 249:404 (1990); Cwirla et al., Science 276: 1696-99 (1997); U.S. Pat. No. 5,223,409; U.S. Pat. No. 5,733,731; U.S. Pat. No. 5,498,530; U.S. Pat. No. 5,432,018; U.S. Pat. No. 5,338,665; 1994; U.S. Pat. No. 5,922,545; International Application Publication Nos. WO 96/40987 and WO 98/15833). In phage display peptide libraries, random peptide sequences are fused to a phage coat protein such that the peptides are displayed on the external surface of a filamentous phage particle.

A peptide that is a minimal recognition unit or a CDR (i.e., any one or more of three CDRs present in a heavy chain variable region and/or one or more of three CDRs present in a light chain variable region) may be identified by computer modeling techniques, which can be used for comparing and predicting a peptide sequence that will specifically bind the senescent cell-associated antigen of interest (see, e.g., Bradley et al., Science 309:1868 (2005); Schueler-Furman et al., Science 310:638 (2005)). Such computer-assisted predictive modeling techniques may also be useful for altering the binding affinity of an antibody. Amino acid substitutions may be readily accomplished using any one of a number of mutagenesis techniques described herein and used routinely in the art for making polynucleotide and polypeptide variants.

According to certain embodiments, non-human, human, or humanized heavy chain and light chain variable regions of any of the immunoglobulin molecules described herein may be constructed as scFv polypeptide fragments (single chain antibodies). See, e.g., Bird et al., Science 242:423-426 (1988); Huston et al., Proc. Natl. Acad. Sci. USA 85:5879-83 (1988)). Multi-functional scFv fusion proteins may be generated by linking a polynucleotide sequence encoding an scFv polypeptide in-frame with at least one polynucleotide sequence encoding any of a variety of known effector proteins. These methods are known in the art, and are disclosed, for example, in EP-B1-0318554, U.S. Pat. No. 5,132,405, U.S. Pat. No. 5,091,513, and U.S. Pat. No. 5,476,786. By way of example, effector proteins may include immunoglobulin constant region sequences. See, e.g., Hollenbaugh et al., J. Immunol. Methods 188:1-7 (1995). Other examples of effector proteins are enzymes. As a non-limiting example, such an enzyme may provide a biological activity for therapeutic purposes (see, e.g., Siemers et al., Bioconjug. Chem. 8:510-19 (1997)), or may provide a detectable activity, such as horseradish peroxidase-catalyzed conversion of any of a number of well-known substrates into a detectable product, for diagnostic uses.

Antibodies may also be identified and isolated from human immunoglobulin phage libraries, from rabbit immunoglobulin phage libraries, from mouse immunoglobulin phage libraries, and/or from chicken immunoglobulin phage libraries (see, e.g., Winter et al., Annu. Rev. Immunol. 12:433-55 (1994); Burton et al., Adv. Immunol. 57:191-280 (1994); U.S. Pat. No. 5,223,409; Huse et al., Science 246:1275-81 (1989); Schlebusch et al., Hybridoma 16:47-52 (1997) and references cited therein; Rader et al., J. Biol. Chem. 275:13668-76 (2000); Popkov et al., J. Mol. Biol. 325:325-35 (2003); Andris-Widhopf et al., J. Immunol. Methods 242:159-31 (2000)). Antibodies isolated from non-human species or non-human immunoglobulin libraries may be genetically engineered according to methods described herein and known in the art to humanize the antibody or fragment thereof. Immunoglobulin variable region gene combinatorial libraries may be created in phage vectors that can be screened to select immunoglobulin fragments (Fab, Fv, scFv, or multimers thereof) that bind specifically to the senescent cell associated antigen of interest (see, e.g., U.S. Pat. No. 5,223,409; Huse et al., Science 246:1275-81 (1989); Sastry et al., Proc. Natl. Acad. Sci. USA 86:5728-32 (1989); Alting-Mees et al., Strategies in Molecular Biology 3:1-9 (1990); Kang et al., Proc. Natl. Acad. Sci. USA 88:4363-66 (1991); Hoogenboom et al., J. Molec. Biol. 227:381-388 (1992); Schlebusch et al., Hybridoma 16:47-52 (1997) and references cited therein; U.S. Pat. No. 6,703,015).

In certain other embodiments, antibodies are multimeric antibody fragments. Useful methodologies are described generally, for example in Hayden et al., Curr Opin. Immunol. 9:201-12 (1997) and Coloma et al., Nat. Biotechnol. 15:159-63 (1997). For example, multimeric antibody fragments may be created by phage techniques to form miniantibodies (U.S. Pat. No. 5,910,573) or diabodies (Holliger et al., Cancer Immunol. Immunother. 45:128-30 (1997)). Multimeric fragments may be generated that are multimers of a viral coat protein-specific Fv. Multimeric antibodies include bispecific and bifunctional antibodies comprising a first Fv specific for an antigen (e.g., E-selectin) associated with a second Fv having a different antigen specificity (see, e.g., Drakeman et al., Expert Opin. Investig. Drugs 6:1169-78 (1997); Koelemij et al., J. Immunother. 22:514-24 (1999); Marvin et al., Acta Pharmacol. Sin. 26:649-58 (2005); Das et al., Methods Mol. Med. 109:329-46 (2005)). In an exemplary embodiment, the recombinant antibody comprises at least two Fv regions (bivalent), and in other embodiments may comprise 3 or more Fv regions (i.e., multivalent). In certain embodiments, the bivalent and multivalent Fv regions each specifically bind to different senescent cell associated antigens; in other embodiments, the bivalent and multivalent regions each bind to different epitopes of the same senescent cell associated antigen. By way of non-limiting example, a bivalent recombinant antibody comprises an Fv region specific for human or mouse p16INK4a and a second Fv region that is specific for a different SCAAg (e.g., a SCAAg listed in Table 1 or a SCAAg that is encoded by a nucleotide sequence selected from Table 2 or Table 3).

Immunoglobulin framework and constant region sequences are available in the art, for example, in Kabat et al. (in Sequences of Proteins of Immunological Interest, 4th ed., (U.S. Dept. of Health and Human Services, U.S. Government Printing Office, 1991); see also Kabat databases available on the Internet). In a particular embodiment, the recombinant antibody comprises an Fc (constant region) derived from a human immunoglobulin. In a more specific embodiment, the Fc regions is derived from an immunoglobulin class, such as IgG, that mediates effector functions that facilitate clearance of a senescence cell from a tissue of a subject immunized with an immunogenic composition described herein,

Antibodies that bind to specific cell-surface antigens on target cells (e.g., a senescent cell) can induce cytotoxicity via effector functions of antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cell-mediated phagocytosis, and complement-dependent cytotoxicity (CDC) through the Fc region of the antibody, and apoptosis of target cells directly (see, e.g., Shan et al., 2000, Cancer Immunol. Immunother. 48:673-683; Carter et al., 2001, Nat. Rev. Cancer 1:118-129; Glennie et al., 2003, Drug Discov. Today 8:503-510; Smith et al., 2003, Oncogene 22:7359-7368; Weiner and Carter, 2005, Nat. Biotechnol. 23:556-7). The cell mediated reaction where non-specific cytotoxic cells that express Fcγ receptors recognize bound antibody on a target cell and subsequently causes lysis of the target cell is known as antibody dependent cell mediated cytotoxicity (ADCC) (see, e.g., Raghavan et al., 1996, Annu. Rev. Cell. Dev. Biol. 12:181-220). Another important Fc ligand is the complement protein C1q, the binding of which mediates complement dependent cytotoxicity (see, e.g., Ward et al, 1995, Ther. Immunol. 2:77-94). Binding of C1q to at least two IgGs is sufficient to activate the classical complement cascade, causing osmotic lysis of target cells. Animal models and clinical trials suggest an important role for Fc receptors and ADCC in clinical efficacy of antibody therapies (see, e.g., Clynes et al., 2000, Nat. Med. 6:443-446; de Haij et al., 2010, Cancer Res. 70:3209-3217; Weng and Levy, 2003, J. Clin. Oncol. 21:3940-3947). In certain embodiments, antibody therapies specific for a senescent cell associated antigen may be modified to enhance ADCC activity.

For IgG antibodies, ADCC and ADCP require the engagement of the Fc region of an antibody that is bound to the surface of a target cell with Fcγ receptors (FcγRs) (see, e.g., Cohen-Solal et al., 2004, Immunol. Lett. 92:199-205). In humans, FcγRs comprise FcγRI (CD64); FcγRII (CD32), including FcγRIIa, FcγRIIb, and FcγRIIc isoforms; and FcγRIII (CD16), including FcγRIIIa and FcγRIIIb isoforms (see, e.g., Jefferis et al., 2002, Immunol. Lett. 82:57-65; Raghavan et al., 1996, Annu. Rev. Cell Dev. Biol. 12:181-220). FcγRs are expressed on a variety of immune cells. Binding of Fe/FcγR complex recruits these cells to sites of bound antigen, resulting in signaling and subsequent immune responses such as release of inflammation mediators, activation of B cells, endocytosis, phagocytosis, and cytoxicity. FcγRs have varying affinity for the same Fc region (FcγRI high, FcγRII and FcγRIII low). While FcγRI, FcγRIIa/c, and FcγRIII are activating receptors characterized by an intracellular immunoreceptor tyrosine-based activation motif (ITAM), FcγRIIb has an intracellular immunoreceptor tyrosine-based inhibition motif (ITIM) and is accordingly an inhibitor receptor.

IgG molecules comprise an N-linked oligosaccharide covalently linked at a conserved N297 (EU numbering system, Kabat et al., supra) residue of each of the CH2 domains of the Fc region. The oligosaccharides found in the Fc region of serum IgGs are mostly biantennary glycans of the complex type. Variations of IgG glycosylation patterns include attachment of terminal sialic acid, a third GlcNAc arm (bisecting GlcNAc), a terminal galactosylation, and α-1,6-linked core fucosylation. Oligosaccharides may contain zero (G0), one (G1) or two (G2) galactoses. The precise pattern of glycosylation depends on the structural properties of IgG subcomponents, in particular, the CH2 and CH3 domains (see, e.g., Lund et al., 2000, Eur. J. Biochem. 267:7246-7257). The cell lines used for recombinant monoclonal antibody synthesis may also influence oligosaccharide chain synthesis. The oligosaccharide moiety of glycoproteins is initially synthesized by the cell from lipid-linked oligosaccharides to form Glc 3 Man 9 GlcNAc 2 -pyrophosphoryl-dolichol, which is transferred to the protein in the endoplasmic reticulum. The oligosaccharide portion is then sequentially processed. First, all three glucose resides are removed by glucosidases I and II to yield Man 9 GlcNAc 2 -protein. Further removal of a number of mannose residues may occur. Initially, four α1,2-linked mannoses are removed to yield a Man 5 GlcNAc 2 -protein, which is then elongated by the addition of a N-acetylglucosamine (GlcNAc) residue, producing GlcNAcMan 5 GlcNAc 2 -protein. Mannosidase II then removes the α1,3- and α1,6-linked mannoses. Then, other sugars, GlcNAc, galactose, and sialic acid, are added sequentially to yield the complex structures often found on glycoproteins.

Methods of enhancing Fc receptor binding include Fc amino acid modification and modification of Fc carbohydrate structures. For immunoglobulins, it has been demonstrated that the attachment of an N-linked oligosaccharide to Asn-297 of the CH2 domain is critical for ADCC activity. Removal of the N-linked oligosaccharide through mutation of the N-linked consensus site or by enzymatic means results in little or no ADCC activity. Removal of the core α-1,6-fucose moiety from IgG1 Fc oligosaccharides has been demonstrated to improve FcγRIII binding and ADCC activity (see, e.g., Carter, 2001, Nat. Rev. Cancer 1:118-129; Kanda et al., Glycobiology, 2006, 17:104-118; Shields et al., 2002 , J. Biol. Chem. 277:26733-26740; Shinkawa et al., 2003 , J. Biol. Chem., 2003, 278:3466-3473; Niwa et al., 2004, Cancer Res. 64:2127-2133). The level of another glycoform, bisected N-linked carbohydrate, has also been suggested to increase ADCC (see, e.g., Umana et al, 1999, Nat. Biotechnol. 17:176-180; Hodoniczky et al., 2005, Biotechnol. Prog. 21:1644-52)

Compositions and methods for producing antibody-based therapies with modified glycosylation pattern of the Fc region are known in the art. For example, inhibition or disruption of glycoprotein processing may be used to modify Fc glycosylation to enhance ADCC (see, e.g., Rothman et al., 1989 , Mol. Immunol. 26:1113-23). Antibodies produced from castanospermine-treated hybridomas also exhibited enhanced ADCC by NK cells (see, e.g., Kaushal and Elbein, 1995, Methods Enzymol. 230:316-329, incorporated herein in its entirety). U.S. Pat. No. 8,071,336, incorporated herein in its entirety, describes methods of producing antibodies comprising oligomannose-type-N-glycans with enhanced ADCC and higher binding affinity for FcγRIIIA by culturing hybridomas in the presence of kifunesine. Antibody producing cells may be genetically modified to reduce/inhibit expression of enzymes involved in glycoprotein processing. WO2009/114641, incorporated herein in its entirety, describes antibody producing cells lacking GlcNAc transferase I, yielding antibodies with enhanced ADCC. Antibodies with lower fucosylated oligosaccharide and enhanced ADCC have been produced using hybridomas expressing lower α-1,6-fucosyltransferase (see, e.g., Shinkawa et al., 2003 , J. Biol. Chem. 278:3466-3473; European Patent Applic. Pub. No. 1176195, each of which is incorporated herein by reference in its entirety). U.S. Pat. No. 7,931,895, incorporated herein in its entirety, describes antibodies with bi-antennary glycan structures with short chains, low degree of sialylation, and non-intercalated terminal mannoses and/or terminal GlcNAcs that have enhanced ADCC activity. U.S. Patent Publication 2011/0053223, incorporated herein in its entirety, describes methods for making antibodies with Man5 glycans.

A variety of Fc sequence variants with optimized binding affinity for FcγRs and/or enhanced ADCC have been described and are known in the art. By way of example, Fc S239D/I332E double mutants have been shown to have enhanced effector function (see, e.g., Lazar et al., 2006 , Proc. Natl. Acad. Sci. 103:4005-4010, incorporated herein in its entirety). U.S. Patent Publication 2010/0297103, incorporated herein in its entirety, describes constant region positions for cysteine substitutions for enhancing ADCC. Lazar et al. described IgG1 Fc mutations of S298A, E333A, and K334A with optimized FcγR affinity and specificity (see, e.g., Shields et al., J. Biol. Chem. 276:6591-6604 (2001), incorporated herein in its entirety). U.S. Patent Publication 2006/0039904, incorporated herein by reference in its entirety, describes an IgG1 Fc region high effector function amino acid residue 332E, as well as a variety of other Fc residue substitutions for enhancing ADCC. U.S. Pat. No. 8,192,737, incorporated herein in its entirety, describes IgG Fc variants at position 396 with increased ADCC activity.

Also provided herein are methods of manufacture for producing an antibody, or antigen-binding fragment thereof, that specifically binds to a senescent cell associated antigen of interest. For example a process (or method) for manufacturing an antibody may comprise determining the nucleotide sequence that encodes the antibody by using standard molecular biology techniques, including primer design, hybridization, nucleic acid isolation, cloning, and amplification, and sequencing. A polynucleotide comprising a nucleotide sequence encoding the antibody, or antigen-binding fragment thereof, may be incorporated into a recombinant expression construct (i.e., vector) according to well-known methods and principles known in the molecular biology art and described herein for preparing a recombinant expression vector.

The nucleic acid molecules encoding the antibody or antigen binding fragment, as described herein, may be propagated and expressed according to any of a variety of routinely practiced procedures for nucleic acid excision, ligation, transformation, and transfection. Thus, in certain embodiments expression of the antibody or antigen binding fragment may be preferred in a prokaryotic host cell, such as Escherichia coli (see, e.g., Pluckthun et al., Methods Enzymol. 178:497-515 (1989)). In certain other embodiments, the antibody may be expressed in a eukaryotic host cell, including animal cells (including mammalian cells); yeast (e.g., Saccharomyces cerevisiae, Schizosaccharomyces pombe , and Pichia pastoris ); or plant cells. Examples of suitable animal cells include, but are not limited to, myeloma, HEK293, COS, or CHO cells. Examples of plant cells include tobacco, corn, soybean, and rice cells. By methods known to those having ordinary skill in the art and based on the present disclosure, a nucleic acid vector may be designed for expressing foreign sequences in a particular host system, and then polynucleotide sequences encoding the cellular polypeptide may be inserted. The regulatory elements will vary as appropriate for the particular host.

Immune Response

An immune response that results in clearance (i.e., removal, elimination, destruction) of senescent cells may include a humoral or cellular immune response or both a humoral and cellular immune response. A humoral immune response has been generally described as a response in which antibodies (i.e., immunoglobulins) specific for antigens are produced by differentiated B lymphocytes. The Fc portion of the immunoglobulin mediates certain effector functions including activation of the classical complement cascade; interaction with effector cells; and compartmentalization of immunoglobulins. Destruction of senescent cells may therefore comprise antibody dependent cell-mediated cytotoxicity (ADCC) or complement fixation and associated complement dependent cytotoxicity (CDC).

Typically, ADCC involves activation of NK cells by antibodies. An NK cell expresses CD16 which is an Fc receptor. This receptor recognizes, and binds to, the Fc portion of an antibody, such as an IgG, which has bound to the surface of a target cell. The most common Fc receptor on the surface of an NK cell is called CD16 or FcγRIII. Once the Fc receptor binds to the Fc region of IgG, the NK cell releases cytokines such as IFN-γ, and cytotoxic granules containing perforin and granzymes that enter the target cell and promote cell death by triggering apoptosis. This is similar to, but independent of, responses by cytotoxic (CTLs).

Cell mediated responses involve various types of T lymphocytes that eliminate antigens, and cells expressing the antigens, by a variety of mechanisms. For example, CD4+ helper T cells that are capable of recognizing specific antigens may release soluble mediators such as cytokines to recruit additional cells of the immune system to participate in an immune response. CD8+ cytotoxic T cells are also capable of recognizing specific antigens and may bind to and destroy or damage an antigen-bearing cell or particle. Cell mediated immune responses also include a cytotoxic T lymphocyte (CTL) response and can be important for elimination of senescent cells.

As described herein, the immune response evoked by any one of the immunogens described herein may include a specific T cell response, a specific B cell response (i.e., production of specific antibodies), or both a specific T cell immune response and B cell immune response in the immunized subject. As used herein, the immune response is said to be “specific for,” “specific to,” or “specifically against” a senescent cell (i.e., specific for one or more senescence cell associated antigens) when the immune response is detectable at a level greater than the level against a non-senescent cell. Also as described herein, the immune response evoked by any one of the immunogens described herein may include production of specific antibodies in the immunized subject. Interaction or binding of an antibody to a specific antigen generally involves electrostatic interactions, hydrogen bonding, Van der Waals interactions, and hydrophobic interactions. Any one of these or any combination thereof can play a role in the binding between an antibody and its antigen. As used herein, an antibody is said to be “specific for” or to “specifically bind” its cognate senescent cell associate antigen (or fragment thereof) or a senescent cell that expresses the antigen when the antibody reacts at a detectable level with the respective immunogen, preferably with an affinity constant, K a , of greater than or equal to about 10 4 M −1 , or greater than or equal to about 10 5 M −1 , greater than or equal to about 10 6 M −1 , greater than or equal to about 10 7 M −1 , or greater than or equal to 10 8 M −1 . The ability of the antibody to bind to its cognate ligand may also be expressed as a dissociation constant K D , and an antibody is said to specifically bind its cognate ligand if it binds with a K D of less than or equal to 10 −4 M, less than or equal to about 10 −5 M, less than or equal to about 10 −6 M, less than or equal to 10 −7 M, or less than or equal to 10 −8 M.

Affinities of an antibody for a senescent cell associate antigen described herein, can be readily determined using conventional techniques, for example, those described by Scatchard et al. ( Ann. N.Y. Acad. Sci. USA 51:660 (1949)) and by surface plasmon resonance (SPR; BIAcore™, Biosensor, Piscataway, N.J.). For surface plasmon resonance, target molecules are immobilized on a solid phase and exposed to ligands in a mobile phase running along a flow cell. If ligand binding to the immobilized target occurs, the local refractive index changes, leading to a change in SPR angle, which can be monitored in real time by detecting changes in the intensity of the reflected light. The rates of change of the surface plasmon resonance signal can be analyzed to yield apparent rate constants for the association and dissociation phases of the binding reaction. The ratio of these values gives the apparent equilibrium constant (affinity) (see, e.g., Wolff et al., Cancer Res. 53:2560-65 (1993)).

The immunological status, including the presence, level, or extent of a specific immune response, of a subject before, during, and after active immunization with an immunogen described herein or passive immunization with a recombinant antibody described herein (or composition comprising the immunogen or antibody) may be monitored. Induction and production of cytokines and other immune modulators can be determined by methods and techniques routinely practiced in the art for determining the level of immune modulators and cytokines in a biological sample obtained from the subject before, during, and/or after treatment. An immune response, including activation and proliferation of immune cells and level of specific antibodies, in a subject may be determined by any number of well-known immunological techniques and methods with which those having ordinary skill in the art will be readily familiar. Such assays include, but need not be limited to, in vivo or in vitro determination of the presence or level of one or more cytokines (e.g., IFN-γ, IL-2, IL-4, and IL-12, and also IL-6, IL-1β, leukemia inhibitory factor, TNF-α, IL-10), lymphokines, chemokines, hormones, growth factors, and the like. Cellular activation state changes may also be determined, for example, by determining altered functional or structural properties of cells of the immune system, for example cell proliferation, altered motility, induction of specialized activities such as specific gene expression or cytolytic behavior; cellular differentiation by cells of the immune system, including altered surface antigen expression profiles or the onset of apoptosis (programmed cell death). Procedures for performing these and similar assays may be found, for example, in Lefkovits ( Immunology Methods Manual: The Comprehensive Sourcebook of Techniques, 1998). See also Current Protocols in Immunology ; Weir, Handbook of Experimental Immunology , Blackwell Scientific, Boston, Mass. (1986); Mishell and Shigii (eds.) Selected Methods in Cellular Immunology , Freeman Publishing, San Francisco, Calif. (1979); Green and Reed, Science 281:1309 (1998)) and references cited therein. Immunoassays to determine the level of specific anti-senescent cell antigen antibodies in a subject are also routinely practiced in the art and described herein.

A “biological sample” may include a sample from a subject, and may be a blood sample (from which serum or plasma may be prepared), a biopsy specimen, one or more body fluids (e.g., lung lavage, ascites, mucosal washings, synovial fluid), bone marrow, lymph nodes, tissue explant, organ culture, or any other tissue or cell preparation from the subject or a biological source. A biological sample may further refer to a tissue or cell preparation in which the morphological integrity or physical state has been disrupted, for example, by dissection, dissociation, solubilization, fractionation, homogenization, biochemical or chemical extraction, pulverization, lyophilization, sonication, or any other means for processing a sample derived from a subject or biological source. In certain embodiments, the subject or biological source may be a human or non-human animal, a primary cell culture (e.g., immune cells), or culture adapted cell line, including but not limited to, genetically engineered cell lines that may contain chromosomally integrated or episomal recombinant nucleic acid sequences, immortalized or immortalizable cell lines, somatic cell hybrid cell lines, differentiated or differentiatable cell lines, transformed cell lines, and the like.

Animal models are also available for determining the effect of the immunogens described herein on age-sensitive traits. Such traits include for example T cell subset distribution, cataract formation, spontaneous activity, motor coordination, and cognitive capacity, physical function, body composition (e.g., sarcopenia, osteoporosis, loss of fat mass) and cardiac function. In animal models, physical function can be assessed, for example, by measuring running time, distance and work using a motorized treadmill, and grip strength using a grip meter, according to previously described protocols (e.g., Zhang et al., Animal Models of Inflammatory Pain, Neuromethods , Volume 49, Oct. 20, 2010, 23-40; Balkaya et al., Behavioral Testing in Mouse Models of Stroke, Neuromethods , Volume 47, 2010, 179-197). Lean mass, fat mass and bone mineral density can be assessed, for example, by QNMR and/or dual-energy X-ray absorptiometry measurements as previously described (e.g., Reed et al., Physiology & Behavior , Vol. 91, 2007, 593-600; Halldorsdottir et al., Int. J. Body Compos. Res., 2009; 7(4), 147-154; Brommage et al., AJP—Endo, Sep. 1, 2003, Vol. 285, No. 3 E454-E459). Methods and techniques are also available for assessing many of these traits in human subjects.

Spontaneous activity of individual mice can be measured, for example, over a 48-hour period using comprehensive laboratory animal monitoring systems equipped with photocells (e.g., Columbus Instruments) as previously described (e.g., Handschin et al., J. Biol. Chem., Vol. 282, 41, 30014, Oct. 12, 2007; Pack et al., Physiol. Genomics (Sep. 19, 2006)). Motor coordination can be analyzed, for example, by performing an accelerating rotarod test. For measuring cognitive capacity, a modified Stone T-maze, which is sensitive to age-related changes in learning and memory, can be used. In animal models, illustrative age-sensitive traits and the benefit of immunization with an immunogenic composition described herein can be measured using tissues and organs of test and control mice, including fiber diameter analysis on gastrocnemius muscle, DNA damage analysis, analysis of renal and glomerulosclerosis, analysis for retinal atrophy, proteotoxic stress analysis, oxidative stress analysis, analysis of the hematopoietic system, and the like.

Methods of Treating Diseases, Disorders, and Conditions by Immunization

The immunogens, immunogenic compositions, and methods described herein are useful for treating diseases, disorders, and conditions that are treatable or preventable by clearing (i.e., removing, destroying, eliminating) senescent cells from a tissue in the subject receiving the immunization. Protocols for administering an immunogenic composition described herein may be readily established by a person skilled in the art. Typically, after administering an initial dose of an immunogenic composition comprising an immunogen (also called the primary immunization) to a subject, one, two or more doses of the immunogenic composition (also called boosting or booster doses) are administered. Administration of one or more booster immunizations may vary according to, inter alia, the immunogen, the adjuvant (if any), the co-stimulatory molecule (if any) and/or the particular animal species. As described herein, the level of an immune response (B cell, T cell, or both) after the first and each administration of an immunogen may be determined by methods described herein and in the art.

In certain embodiments, the immunogenic composition comprises a recombinant antibody(ies) that specifically bind to a SCAAg. The pharmacokinetics and clearance of the antibody can be monitored by using any one or more of the immunoassays described herein and routinely practiced in the art. The immunogenicity of the recombinant antibody can also be monitored to determine whether the recombinant antibody is evoking an undesired anti-recombinant antibody immune response.

As understood by a person skilled in the medical art, the terms, “treat” and “treatment,” refer to medical management of a disease, disorder, or condition of a subject (i.e., patient) (see, e.g., Stedman's Medical Dictionary). In general, an appropriate dose and treatment regimen provide the immunogen in an amount sufficient to provide therapeutic and/or prophylactic benefit. Therapeutic and/or prophylactic benefit includes, for example, an improved clinical outcome, both therapeutic treatment and prophylactic or preventative measures, wherein the object is to prevent or slow or retard (lessen) an undesired physiological change or disorder, or to prevent or slow or retard (lessen) the expansion or severity of such disease or disorder. Beneficial or desired clinical results from treating a subject include, but are not limited to, abatement, lessening, or alleviation of symptoms that result from or are associated the disease or disorder to be treated; decreased occurrence of symptoms; improved quality of life; longer disease-free status (i.e., decreasing the likelihood or the propensity that a subject will present symptoms on the basis of which a diagnosis of a disease is made); diminishment of extent of disease; stabilized (i.e., not worsening) state of disease; delay or slowing of disease progression; amelioration or palliation of the disease state; and remission (whether partial or total), whether detectable or undetectable; and/or overall survival. “Treatment” can also mean prolonging survival when compared to expected survival if a subject were not receiving treatment. Subjects in need of treatment include those who already have the disease or disorder as well as subjects prone to have or at risk of developing the disease or disorder, and those in which the disease, condition, or disorder is to be prevented (i.e., decreasing the likelihood of occurrence or recurrence of the disease or disorder). A subject may have a genetic predisposition for developing a disease or disorder that would benefit from clearance of senescent cells or may be of a certain age wherein immunization would provide clinical benefit to delay development or reduce severity of a disease, such as an age-related disease or disorder.

A subject (i.e., patient, individual) in need of the therapeutic methods described herein is a human or non-human animal. The subject in need of medical therapies with enhanced efficacy may exhibit symptoms or sequelae of a disease described herein or may be at risk of developing the disease. Non-human animals that may be treated include mammals, for example, non-human primates (e.g., monkey, chimpanzee, gorilla, and the like), rodents (e.g., rats, mice, gerbils, hamsters, ferrets, rabbits), lagomorphs, swine (e.g., pig, miniature pig), equine, canine, feline, bovine, and other domestic, farm, and zoo animals.

An age-related disorder or disease or an age-sensitive trait may be associated with a senescence-inducing stimulus. The efficacy of immunization as described herein may be manifested by reducing the number of symptoms of an age-related disorder or age-sensitive trait associated with a senescence-inducing stimulus, decreasing the severity of one or more symptoms, or delaying the progression of an age-related disorder or age-sensitive trait associated with a senescence-inducing stimulus. In other particular embodiments, preventing an age-related disorder or age-sensitive trait associated with a senescence-inducing stimulus refers to preventing or delaying onset of an age-related disorder or age-sensitive trait associated with a senescence-inducing stimulus, or reoccurrence of one or more age-related disorder or age-sensitive trait associated with a senescence-inducing stimulus. The effectiveness of an immunogenic composition described herein to evoke a beneficial immune response against senescent cells can readily be determined by a person skilled in the medical and clinical arts. One or any combination of diagnostic methods, including physical examination, assessment and monitoring of clinical symptoms, and performance of analytical tests and methods described herein, may be used for monitoring the health status of the subject. The effects of immunization can be analyzed using techniques known in the art, such as comparing symptoms of patients suffering from or at risk of a particular disease or disorder that have received the immunogenic composition with those of patients without such immunization or with placebo treatment.

In one embodiment, methods are provided for treating or preventing diseases or disorders related to, associated with, or caused by cellular senescence including age-related diseases and disorders. Exemplary diseases or disorders that may be treated or prevented by administering an immunogenic composition described herein include, without limitation, cognitive diseases (e.g., Alzheimer's disease and other dementias); cardiovascular disease; diabetes; motor function diseases and disorders (e.g., Parkinson's disease); cancer occurrence, cancer metastasis, cardiovascular disease, cerebrovascular disease, emphysema, osteoarthritis, peripheral vascular disease, cardiac diastolic dysfunction, benign prostatic hypertrophy, aortic aneurysm, and emphysema. Evoking an immune response that comprises clearance of senescence cells by employing the immunization methods described herein may also be useful for treating or reducing the likelihood of cancer or cancer metastasis (exemplary cancers include melanoma, prostate cancer, testicular cancer, breast cancer, brain cancer, pancreatic cancer, colon cancer, thyroid cancer, stomach cancer, lung cancer, ovarian cancer, Kaposi's sarcoma, skin cancer (including squamous cell skin cancer), renal cancer, head and neck cancers, throat cancer, squamous carcinomas that form on the moist mucosal linings of the nose, mouth, throat, etc.), bladder cancer, osteosarcoma (bone cancer), cervical cancer, endometrial cancer, esophageal cancer, liver cancer, and kidney cancer; those that occur in blood, bone marrow, and lymph nodes and include generally, leukemias (myeloid and lymphocytic), lymphomas (e.g., Hodgkin lymphoma), and melanoma (including multiple myeloma). Leukemias include for example, acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), chronic myelogenous leukemia (CML), and hairy cell leukemia).

The efficacy of the immunization methods may be determined and monitored by assessing one or more age-sensitive traits. Such traits include for example T cell subset distribution, cataract formation, spontaneous activity, motor coordination, and cognitive capacity, physical function, body composition (e.g., sarcopenia, osteoporosis, loss of fat mass) and cardiac function. These exemplary age-sensitive traits can be assessed using standard techniques known and available in the art. In a related embodiment, the lean mass, fat mass and bone mineral density are measured by QNMR, dual-energy X-ray absorptiometry, MRI, PET, or a combination thereof. In another related embodiment, the physical function is a measure of (1) running time, distance, and work using a motorized treadmill, (2) grip strength using a grip meter, or (3) any combination measure thereof. In another embodiment, the age-sensitive trait is a measure of a tissue or organ, wherein the measure is of fiber diameter on gastrocnemius muscle, DNA damage, renal and glomerulosclerosis, retinal atrophy, proteotoxic stress, oxidative stress, or hematopoietic system.

In certain embodiments, the immunogenic compositions described herein are administered to a subject who has a cancer or who is at risk of developing cancer. The immunogens and recombinant antibodies described herein that evoke an immune response that results in clearance of senescent cells may be used in combination with chemotherapy, radiotherapy, or both to provide clinical benefit to the subject. Therapeutic benefit includes any one or more of reducing the size of the tumor(s), inhibiting tumor progression, inhibiting tumor growth, delaying tumor colonization, and/or inhibiting, preventing, or delaying metastasis of a tumor. Enhancing the effectiveness of the chemotherapy or radiotherapy may include preventing, slowing, or decreasing development of resistance of the cancer (i.e., tumor or tumors) to the chemotherapy or radiotherapy, thereby allowing additional cycles of therapy and/or decreasing the time interval between cycles of therapy.

An age-related disease or disorder includes diabetes and can be associated with cellular senescence. Therefore, clearance of senescent cells from a subject by administering an immunogenic composition described herein may provide therapeutic benefit. Subjects suffering from type 2 diabetes can be identified using standard diagnostic methods known in the art for type 2 diabetes. Generally, diagnosis of type 2 diabetes is based on symptoms (e.g., increased thirst and frequent urination, increased hunger, weight loss, fatigue, blurred vision, slow-healing sores or frequent infections, and/or areas of darkened skin), medical history, and/or physical examination of a patient. Subjects at risk of developing type 2 diabetes include those having a family history of type 2 diabetes and those having other risk factors such as weight, fat distribution, inactivity, race, age, prediabetes, and/or gestational diabetes. Clinical benefit and improvement of a subject who has diabetes may be evaluated by stability of glucose levels. For example, an increase in the length of time between doses of insulin or a decrease in the dose of insulin required to maintain proper glucose levels in patients who receive an immunogenic composition described herein indicates improved effectiveness of the insulin. Other clinical parameters that may be monitored include level of insulin tolerance, energy expenditure, body composition, fat tissue, skeletal muscle, liver inflammation, lipotoxicity (muscle and liver lipid by imaging in vivo and muscle, liver, bone marrow, and pancreatic β-cell lipid accumulation and inflammation by histology).

Other age-related diseases or disorders that may be associated with cellular senescence are neurological diseases such as Alzheimer's disease, Parkinson's disease, mild cognitive impairment (MCI), and Motor Neuron Dysfunction (MND). Therefore, clearance of senescent cells from a subject who has or who is at risk of developing such a neurological disease may benefit by receiving an immunogenic composition described herein.

Subjects suffering from Alzheimer's disease can be identified using standard diagnostic methods known in the art for Alzheimer's disease. Generally, diagnosis of Alzheimer's disease is based on symptoms (e.g., progressive decline in memory function, gradual retreat from and frustration with normal activities, apathy, agitation or irritability, aggression, anxiety, sleep disturbance, dysphoria, aberrant motor behavior, disinhibition, social withdrawal, decreased appetite, hallucinations, dementia), medical history, neuropsychological tests, neurological and/or physical examination of a patient. Cerebrospinal fluid may also be for tested for various proteins that have been associated with Alzheimer pathology, including tau, amyloid beta peptide, and AD7C-NTP. Genetic testing is also available for early-onset familial Alzheimer disease (eFAD), an autosomal-dominant genetic disease. Clinical genetic testing is available for individuals with AD symptoms or at-risk family members of patients with early-onset disease. In the U.S., mutations for PS2, and APP may be tested in a clinical or federally approved laboratory under the Clinical Laboratory Improvement Amendments. A commercial test for PS1 mutations is also available (Elan Pharmaceuticals).

Subjects at risk of developing Alzheimer's disease include those of advanced age, those with a family history of Alzheimer's disease, those with genetic risk genes (e.g., ApoE4) or deterministic gene mutations (e.g., APP, PS1, or PS2), and those with history of head trauma or heart/vascular conditions (e.g., high blood pressure, heart disease, stroke, diabetes, high cholesterol).

Subjects suffering from MCI can be identified using standard diagnostic methods known in the art for MCI. Criteria for an MCI diagnosis typically include: an individual's report of his or her own memory problems; measurable, greater-than-normal memory impairment detected with standard memory assessment tests; normal general thinking and reasoning skills; and ability to perform normal daily activities. Generally, diagnosis of MCI is based on medical history, assessment of independent function and daily activities, assessment of mental status, neurological examination, evaluation of mood, laboratory tests including blood tests and imaging of the brain's structure of a patient. Exemplary assessments include Clinical Dementia Rating (CDR) scores (a CDR rating of about 0.5 or about 0.5 to 1.0 is often considered clinically relevant MCI) and simple memory test (paragraph recall) to establish an objective memory deficit in combination of a measure of general cognition (mini-mental state exam) to exclude a broader cognitive decline beyond memory (see, Grundman et al., Arch Neurol. 61: 59-66, 2004). In certain embodiments, subjects suffering from MCI may also suffer from Parkinson's disease or have one or more symptoms commonly associated with Parkinson's disease.

Preventing Parkinson's disease as used herein refers to preventing or delaying onset of Parkinson's disease or reoccurrence of one or more symptoms. Symptoms of Parkinson's disease are known in the art and include, but are not limited to, difficulty starting or finishing voluntary movements, jerky, stiff movements, muscle atrophy, shaking (tremors), and changes in heart rate, but normal reflexes, bradykinesia, and postural instability.

Subjects suffering from Parkinson's disease can be identified using standard diagnostic methods known in the art for Parkinson's disease. Generally, diagnosis of Parkinson's disease is based on symptoms, medical history, and neurological and/or physical examination of a patient. Subjects at risk of developing Parkinson's disease include those having a family history of Parkinson's disease and those exposed to pesticides (e.g., rotenone or paraquat), herbicides (e.g., agent orange), or heavy metals.

Subjects suffering from MND exhibit weakness, wasting, and loss of control of muscles. Some diseases affect all muscles (amyotrophic lateralsclerosis), and other diseases cause weakness and loss of function in particular muscles. Subjects develop wasting, uncontrollable twitching, spasticity (stiffness), and movements become slow and effortful. Subjects suffering from MND can be identified using standard diagnostic methods known in the art for MND. Subject are given a physical exam and neurological exam, which assesses motor and sensory skills, nerve function, hearing and speech, vision, coordination and balance, mental status, and changes in mood or behavior. To measure muscle involves the following may be performed: electromyography; laboratory tests to assess the presence of inflammation and/or infection and to measure protein creatine kinase; magnetic resonance imaging; muscle or nerve biopsies; and transcranial magnetic stimulation. Subjects at risk of developing MND include those who have genetic mutations associated with a particular MND. In adults, MNDs occur more commonly in men than in women, with symptoms appearing after age 40.

Cardiovascular disease includes high blood pressure, coronary heart disease, and heart disease, and many factors contribute to development of cardiovascular disease. These factors include aging, smoking, high cholesterol, and calcification of the cardiovascular tissue (Heart Disease and Stroke Statistics-2012 Update: A Report from the American Heart Association. Circulation (2012), 125:e5-e220 (“Heart Disease Statistics”)). Subjects suffering from cardiovascular disease can be identified using standard diagnostic methods known in the art for cardiovascular disease. Generally, diagnosis of atherosclerosis and other cardiovascular disease is based on symptoms (e.g., chest pain or pressure (angina), numbness or weakness in arms or legs, difficulty speaking or slurred speech, drooping muscles in face, leg pain, high blood pressure, kidney failure and/or erectile dysfunction), medical history, and/or physical examination of a patient. Subjects at risk of developing cardiovascular disease include those having a family history of cardiovascular disease and those having other risk factors such as high blood pressure, high cholesterol, diabetes, obesity and/or smoking.

Cardiovascular disease include angina, arrhythmia, atherosclerosis, cardiomyopathy, congestive heart failure, coronary artery disease (CAD), carotid artery disease, endocarditis, heart attack (coronary thrombosis, myocardial infarction [MI]), high blood pressure/hypertension, hypercholesterolemia/hyperlipidemia, mitral valve prolapsed, peripheral artery disease (PAD) and stroke. The benefit to a subject who received an immunogenic composition described herein may be monitored using any known and established techniques, illustrative examples of which include detection or signs of narrowed, enlarged or hardened arteries during a physical exam. These include a weak or absent pulse below the narrowed area of an artery, decreased blood pressure in an affected limb, whooshing sounds (bruits) over the arteries heard using a stethoscope, signs of a pulsating bulge (aneurysm) in the abdomen or behind the knee and/or evidence of poor wound healing in an area where blood flow is restricted. Additional diagnostic tests for monitoring the effectiveness of an immunization method described herein may be performed, such as blood tests to detect cholesterol levels and blood sugar levels, Doppler ultrasound, ankle-brachial index testing, electrocardiogram (ECG), stress tests, cardiac catheterization and angiograms and/or other imaging tests.

Another age-related disease that may be treated by immunizing a subject in need with any one of the immunogenic compositions described herein is pulmonary fibrosis. Symptoms of pulmonary fibrosis are known in the art and include shortness of breath, particularly during exercise; dry, hacking cough; fast, shallow breathing; gradual unintended weight loss; tiredness; aching joints and muscles; and clubbing (widening and rounding of the tips of the fingers or toes). Subjects suffering from pulmonary fibrosis can be identified and monitored using standard diagnostic methods known in the art for pulmonary fibrosis. Generally, diagnosis of pulmonary fibrosis is based on one or more of the following exams or tests: physical exam, patient's medical history, patient's family's medical history, chest X-ray, lung function tests, blood test, bronchoalveolar lavage, lung biopsy, CT scan, and exercise testing.

Subjects at risk of developing pulmonary fibrosis include those exposed to environmental or occupational pollutants, such as asbestosis and silicosis; who smokes cigarettes; having some typical connective tissue diseases such as rheumatoid arthritis, SLE and scleroderma; having other diseases that involve connective tissue, such as sarcoidosis and Wegener's granulomatosis; having infections; taking certain medications (e.g., amiodarone, bleomycin, busufan, methotrexate, and nitrofurantoin); those subject to radiation therapy to the chest; and those whose family member has pulmonary fibrosis.

The immunization protocol used in the methods described herein will be designed dependent upon the disease or disorder to be treated, age of the subject, and on other factors with which a person skilled in the art may use to determine suitability of a subject for the immunization. For example, if a human subject is to be immunized to prevent or treat an age-related disease or disorder, an initial (i.e., primary) immunization may be administered after age 40, 45, 50, 55, 60, or older. Immunization to induce an immune response against senescent cells may also be initiated at an earlier age when the subject's health indicates initiating immunization independent of age is indicated. For example, a subject who is at risk of developing diabetes includes a subject who is overweight. By way of another example, a subject who has been diagnosed with a cancer and will receive chemotherapy, radiation, or both may benefit from the immunization methods described herein.

Pharmaceutically Suitable Immunogenic Compositions

Also provided herein are pharmaceutically suitable immunogenic compositions comprising any one or more of the immunogens described herein or a recombinant antibody described herein for evoking an immune response specific for a senescent cell. Immunogenic compositions may also be called herein immunogenic preparations, which preparations may comprise at least one immunogen and a pharmaceutically acceptable excipient. The immunogenic composition may be a sterile aqueous or non-aqueous solution, suspension or emulsion, which additionally comprises a physiologically acceptable excipient (pharmaceutically acceptable or suitable excipient or carrier) (i.e., a non-toxic material that does not interfere with the activity of the active ingredient). The excipients described herein are merely exemplary and are in no way limiting. An effective amount or therapeutically effective amount refers to an amount of the immunogen or antibody administered to a subject, either as a single dose or as part of a series of doses, which is effective to produce a desired therapeutic effect.

Subjects may generally be monitored for therapeutic effectiveness using assays suitable for the condition being treated or prevented, which assays will be familiar to those having ordinary skill in the art and are described herein. The level of an immunogen or recombinant antibody that is administered to a subject may be monitored by determining the level of the immunogen or recombinant antibody, respectively, in a biological fluid, for example, in the blood, blood fraction (e.g., serum), and/or in the urine, and/or other biological sample from the subject. Any method practiced in the art to detect the immunogen or recombinant antibody may be used to measure the level of immunogen or recombinant antibody, respectively, during the course of a immunization regimen.

The dose of an immunogen or recombinant antibody described herein for evoking a specific immune response may depend upon the subject's condition, that is, stage of the disease if present, severity of symptoms caused by the disease, general health status, as well as age, gender, and weight, and other factors apparent to a person skilled in the medical art. Immunogenic compositions may be administered in a manner appropriate to the disease or disorder to be treated or prevented as determined by persons skilled in the medical arts. An appropriate dose and a suitable duration and frequency of administration will be determined by such factors as the condition of the patient, the type and severity of the patient's disease, the particular form of the active ingredient, and the method of administration. Optimal doses of an immunogen or recombinant antibody may generally be determined using experimental models and/or clinical trials. The optimal dose may depend upon the body mass, weight, or blood volume of the subject. The use of the minimum dose that is sufficient to provide an effective immune response is usually preferred. Design and execution of pre-clinical and clinical studies for an agent (including when administered for prophylactic benefit) described herein are well within the skill of a person skilled in the relevant art. For example, an amount of an immunogen or recombinant antibody may be administered at a dose between 0.01 mg/kg and 1000 mg/kg (e.g., about 0.1 to 1 mg/kg, about 1 to 10 mg/kg, about 10-50 mg/kg, about 50-100 mg/kg, about 100-500 mg/kg, or about 500-1000 mg/kg) body weight.

The immunogenic compositions may be administered to a subject in need thereof by any one of several routes that effectively deliver an effective amount of the immunogen or recombinant antibody. Such administrative routes include, for example, oral, topical, parenteral, enteral, rectal, intranasal, buccal, sublingual, intramuscular, transdermal, vaginal, rectal, or by intracranial injection, or any combination thereof. Such compositions may be in the form of a solid, liquid, or gas (aerosol). The administrative route is also determined by the type of immunogen or if the recombinant antibody is being administered. Immunogenic compositions comprising a senescent cell associated antigen, antigenic fragment, or fusion polypeptide may be administered intramuscularly, transdermally, intranasally, for example. Recombinant antibodies are typically administered by a parenteral route, such as intravenously.

Pharmaceutical acceptable excipients are well known in the pharmaceutical art and described, for example, in Rowe et al., Handbook of Pharmaceutical Excipients: A Comprehensive Guide to Uses , Properties, and Safety, 5 th Ed., 2006, and in Remington: The Science and Practice of Pharmacy (Gennaro, 21 st Ed. Mack Pub. Co., Easton, Pa. (2005)). Exemplary pharmaceutically acceptable excipients include sterile saline and phosphate buffered saline at physiological pH. Preservatives, stabilizers, dyes, buffers, and the like may be provided in the immunogenic composition. In addition, antioxidants and suspending agents may also be used. In general, the type of excipient is selected based on the mode of administration, as well as the chemical composition of the active ingredient(s). Alternatively, compositions described herein may be formulated as a lyophilizate, or the immunogen or recombinant antibody may be encapsulated within liposomes using technology known in the art. Immunogenic compositions may be formulated for any appropriate manner of administration described herein and in the art.

A composition (e.g., for oral administration or delivery by injection) may be in the form of a liquid. A liquid immunogenic composition may include, for example, one or more of the following: a sterile diluent such as water for injection, saline solution, preferably physiological saline, Ringer's solution, isotonic sodium chloride, fixed oils that may serve as the solvent or suspending medium, polyethylene glycols, glycerin, propylene glycol or other solvents; antibacterial agents; antioxidants; chelating agents; buffers and agents for the adjustment of tonicity such as sodium chloride or dextrose. A parenteral preparation can be enclosed in ampoules, disposable syringes or multiple dose vials made of glass or plastic. The use of physiological saline is preferred, and an injectable pharmaceutical composition is preferably sterile.

For oral formulations, an immunogen or recombinant antibody described herein can be used alone or in combination with appropriate additives to make tablets, powders, granules or capsules, and if desired, with diluents, buffering agents, moistening agents, preservatives, coloring agents, and flavoring agents. An immunogen or recombinant antibody included in the compositions may be formulated for oral delivery with a buffering agent, flavoring agent, e.g., in a liquid, solid or semi-solid formulation and/or with an enteric coating.

A composition comprising any one of the immunogens or recombinant antibodies described herein may be formulated for sustained or slow release. Such compositions may generally be prepared using well known technology and administered by, for example, oral, rectal or subcutaneous implantation, or by implantation at the desired target site. Sustained-release formulations may contain the immunogen or recombinant antibody dispersed in a carrier matrix and/or contained within a reservoir surrounded by a rate controlling membrane. Excipients for use within such formulations are biocompatible, and may also be biodegradable; preferably the formulation provides a relatively constant level of active component release. The amount of active agent contained within a sustained release formulation depends upon the site of implantation, the rate and expected duration of release, and the nature of the condition to be treated or prevented.

For immunogenic compositions comprising a nucleic acid molecule, the nucleic acid molecule may be present within any of a variety of delivery systems known to those of ordinary skill in the art, including nucleic acid, and bacterial, viral and mammalian expression systems such as, for example, recombinant expression constructs as provided herein. Techniques for incorporating DNA into such expression systems are well known to those of ordinary skill in the art. The DNA may also be “naked,” as described, for example, in Ulmer et al., Science 259:1745-49, 1993 and reviewed by Cohen, Science 259:1691-1692, 1993. The uptake of naked DNA may be increased by coating the DNA onto biodegradable beads, which are efficiently transported into the cells.

Nucleic acid molecules may be delivered into a cell according to any one of several methods described in the art (see, e.g., Akhtar et al., Trends Cell Bio. 2:139 (1992); Delivery Strategies for Antisense Oligonucleotide Therapeutics , ed Akhtar, 1995, Maurer et al., Mol. Membr. Biol. 16:129-40 (1999); Hofland and Huang, Handb. Exp. Pharmacol. 137:165-92 (1999); Lee et al., ACS Symp. Ser. 752:184-92 (2000); U.S. Pat. No. 6,395,713; International Patent Application Publication No. WO 94/02595); Selbo et al., Int. J. Cancer 87:853-59 (2000); Selbo et al., Tumour Biol. 23:103-12 (2002); U.S. Patent Application Publication Nos. 2001/0007666, and 2003/077829). Such delivery methods known to persons having skill in the art, include, but are not restricted to, encapsulation in liposomes, by iontophoresis, or by incorporation into other vehicles, such as biodegradable polymers; hydrogels; cyclodextrins (see, e.g., Gonzalez et al., Bioconjug. Chem. 10:1068-74 (1999); Wang et al., International Application Publication Nos. WO 03/47518 and WO 03/46185); poly(lactic-co-glycolic)acid (PLGA) and PLCA microspheres (also useful for delivery of peptides and polypeptides and other substances) (see, e.g., U.S. Pat. No. 6,447,796; U.S. Patent Application Publication No. 2002/130430); biodegradable nanocapsules; and bioadhesive microspheres, or by proteinaceous vectors (International Application Publication No. WO 00/53722). In another embodiment, the nucleic acid molecules for use in evoking an immune response as described herein can also be formulated or complexed with polyethyleneimine and derivatives thereof, such as polyethyleneimine-polyethyleneglycol-N-acetylgalactosamine (PEI-PEG-GAL) or polyethyleneimine-polyethyleneglycol-tri-N-acetylgalactosamine (PEI-PEG-triGAL) derivatives (see also, e.g., U.S. Patent Application Publication No. 2003/0077829).

Kits with unit doses of an immunogen or recombinant antibody described herein, usually in oral or injectable doses, are provided. Such kits may include a container containing the unit dose, an informational package insert describing the use and attendant benefits of the immunogen or antibody in treating pathological condition of interest, and optionally an appliance or device for delivery of the composition.

Senescent Cell-Associated Antigens and Polynucleotide Sequences Encoding Senescent Cell-Associated Antigens

This application claims the benefit under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 61/732,746 filed Dec. 3, 2012 and U.S. Provisional Application No. 61/747,653, filed Dec. 31, 2013, which applications are incorporated by reference herein in their entirety.

The various embodiments described above can be combined to provide further embodiments. All the U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, applications and publications to provide yet further embodiments.

These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.