title: Innovative DNA vaccine to break immune tolerance against tumor self-antigen.
abstract: Vaccination is, in theory, a safe and effective approach for controlling disseminated or metastatic cancer due to the specificity of the mammalian immune system, yet its success in the clinic has been hampered thus far by the problem of immune tolerance to tumor self-antigen. Here we describe a DNA vaccination strategy that is able to control cancer by overcoming immune tolerance to tumor self-antigen. We engineered a DNA construct encoding a dimeric form of a secreted single-chain trimer of major histocompatibility complex class I heavy chain, β2-microglobulin, and peptide antigen linked to immunoglobulin G (SCT-Ag/IgG). The chimeric protein was able to bind to antigen-specific CD8(+) T cells with nearly 100% efficiency and strongly induce their activation and proliferation. In addition, the chimeric protein was able to coat professional antigen-presenting cells through the F(c) receptor to activate antigen-specific CD8(+) T cells. Furthermore, intradermal vaccination with DNA-encoding SCT-Ag/IgG could generate significant numbers of cytotoxic effector T cells against tumor self-antigen and leads to successful therapeutic outcomes in a preclinical model of metastatic melanoma. Our data suggest that the DNA vaccine strategy described in the current study is able to break immune tolerance against endogenous antigen from melanoma and result in potent therapeutic antitumor effects. Such strategy may be used in other antigenic systems for the control of infections and/or cancers.
authors.affiliation: Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA.
authors.forename: Tae Heung
authors.initials: TH
authors.lastname: Kang
authors.forename: Chih-Ping
authors.initials: CP
authors.lastname: Mao
authors.forename: Victor
authors.initials: V
authors.lastname: La
authors.forename: Alexander
authors.initials: A
authors.lastname: Chen
authors.forename: Chien-Fu
authors.initials: CF
authors.lastname: Hung
authors.forename: T-C
authors.initials: TC
authors.lastname: Wu
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000276:immunology; D001324:Autoantigens / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D019496:Cancer Vaccines / Q000235:genetics / Q000276:immunology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D000939:Epitopes / Q000276:immunology; D005260:Female; D005805:Genes, MHC Class I; D007108:Immune Tolerance; D007074:Immunoglobulin G / Q000235:genetics / Q000276:immunology; D019746:Intramolecular Oxidoreductases / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014162:Transfection; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology*; D001613:beta 2-Microglobulin / Q000235:genetics / Q000276:immunology
chemical_list: D000970:Antineoplastic Agents; D001324:Autoantigens; D019496:Cancer Vaccines; D000939:Epitopes; D007074:Immunoglobulin G; D011993:Recombinant Fusion Proteins; D019444:Vaccines, DNA; D001613:beta 2-Microglobulin; D019746:Intramolecular Oxidoreductases; C042501:dopachrome isomerase