title: Human tumor-derived heat shock protein 96 mediates in vitro activation and in vivo expansion of melanoma- and colon carcinoma-specific T cells.
abstract: Heat shock proteins (hsp) 96 play an essential role in protein metabolism and exert stimulatory activities on innate and adaptive immunity. Vaccination with tumor-derived hsp96 induces CD8(+) T cell-mediated tumor regressions in different animal models. In this study, we show that hsp96 purified from human melanoma or colon carcinoma activate tumor- and Ag-specific T cells in vitro and expand them in vivo. HLA-A*0201-restricted CD8(+) T cells recognizing Ags expressed in human melanoma (melanoma Ag recognized by T cell-1 (MART-1)/melanoma Ag A (Melan-A)) or colon carcinoma (carcinoembryonic Ag (CEA)/epithelial cell adhesion molecule (EpCAM)) were triggered to release IFN-gamma and to mediate cytotoxic activity by HLA-A*0201-matched APCs pulsed with hsp96 purified from tumor cells expressing the relevant Ag. Such activation occurred in class I HLA-restricted fashion and appeared to be significantly higher than that achieved by direct peptide loading. Immunization with autologous tumor-derived hsp96 induced a significant increase in the recognition of MART-1/Melan-A(27-35) in three of five HLA-A*0201 melanoma patients, and of CEA(571-579) and EpCAM(263-271) in two of five HLA-A*0201 colon carcinoma patients, respectively, as detected by ELISPOT and HLA/tetramer staining. These increments in Ag-specific T cell responses were associated with a favorable disease course after hsp96 vaccination. Altogether, these data provide evidence that hsp96 derived from human tumors can present antigenic peptides to CD8(+) T cells and activate them both in vitro and in vivo, thus representing an important tool for vaccination in cancer patients.
mesh_terms: D017951:Antigen Presentation; D000951:Antigens, Neoplasm / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000473:pathology; D019496:Cancer Vaccines / Q000008:administration & dosage / Q000276:immunology; D002455:Cell Division / Q000276:immunology; D045744:Cell Line, Tumor; D002999:Clone Cells; D003110:Colonic Neoplasms / Q000276:immunology* / Q000473:pathology*; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D015234:HLA-A Antigens / Q000276:immunology; D015789:HLA-A2 Antigen; D006360:Heat-Shock Proteins / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology*; D018655:Lymphocyte Count; D008545:Melanoma / Q000276:immunology* / Q000473:pathology*; D010446:Peptide Fragments / Q000276:immunology / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000473:pathology*; D015854:Up-Regulation / Q000276:immunology*
chemical_list: D000951:Antigens, Neoplasm; D019496:Cancer Vaccines; D018984:Epitopes, T-Lymphocyte; D015234:HLA-A Antigens; C435939:HLA-A*02:01 antigen; D015789:HLA-A2 Antigen; D006360:Heat-Shock Proteins; D010446:Peptide Fragments; C052646:sarcoma glycoprotein gp96 rejection antigens