title: Broadening the repertoire of melanoma-associated T-cell epitopes.
abstract: Immune therapy has provided a significant breakthrough in the treatment of metastatic melanoma. Despite the remarkable clinical efficacy and established involvement of effector CD8 T cells, the knowledge of the exact peptide-MHC complexes recognized by T cells on the tumor cell surface is limited. Many melanoma-associated T-cell epitopes have been described, but this knowledge remains largely restricted to HLA-A2, and we lack understanding of the T-cell recognition in the context of other HLA molecules. We selected six melanoma-associated antigens (MAGE-A3, NY-ESO-1, gp100, Mart1, tyrosinase and TRP-2) that are frequently recognized in patients with the aim of identifying novel T-cell epitopes restricted to HLA-A1, -A3, -A11 and -B7. Using in silico prediction and in vitro confirmation, we identified 127 MHC ligands and analyzed the T-cell responses against these ligands via the MHC multimer-based enrichment of peripheral blood from 39 melanoma patients and 10 healthy donors. To dissect the T-cell reactivity against this large peptide library, we used combinatorial-encoded MHC multimers and observed the T-cell responses against 17 different peptide-MHC complexes in the patient group and four in the healthy donor group. We confirmed the processing and presentation of HLA-A3-restricted T-cell epitopes from tyrosinase (TQYESGSMDK) and gp100 (LIYRRRLMK) and an HLA-A11-restricted T-cell epitope from gp100 (AVGATKVPR) via the cytolytic T-cell recognition of melanoma cell lines and/or K562 cells expressing the appropriate antigen and HLA molecule. We further found T-cell reactivity against two of the identified sequences among tumor-infiltrating lymphocytes from melanoma patients, suggesting a potential clinical relevance of these sequences.
authors: Center for Cancer Immune Therapy, Department of Hematology, University Hospital Herlev, Herlev, Denmark.
authors: Thomas Mørch
authors: TM
authors: Frøsig
authors: Rikke
authors: R
authors: Lyngaa
authors: Özcan
authors: Ö
authors: Met
authors: Stine Kiær
authors: SK
authors: Larsen
authors: Marco
authors: M
authors: Donia
authors: Inge Marie
authors: IM
authors: Svane
authors: Per
authors: P
authors: Thor Straten
authors: Sine Reker
authors: SR
authors: Hadrup
mesh_terms: D045744:Cell Line, Tumor; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D006680:HLA Antigens / Q000276:immunology*; D015788:HLA-A1 Antigen / Q000276:immunology; D059870:HLA-A11 Antigen / Q000276:immunology; D015791:HLA-A3 Antigen / Q000276:immunology; D015793:HLA-B7 Antigen / Q000276:immunology; D006801:Humans; D016219:Immunotherapy, Adoptive; D007963:Leukocytes, Mononuclear / Q000166:cytology; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology; D008545:Melanoma / Q000276:immunology*; D058950:Melanoma-Specific Antigens / Q000276:immunology*; D010449:Peptide Mapping; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000637:transplantation
chemical_list: D018984:Epitopes, T-Lymphocyte; D006680:HLA Antigens; D015788:HLA-A1 Antigen; D059870:HLA-A11 Antigen; D015791:HLA-A3 Antigen; D015793:HLA-B7 Antigen; D058950:Melanoma-Specific Antigens