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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: Antigen Presentation, Antigens, Neoplasm, Cells, Cultured, HLA-A2 Antigen, Humans, Immunodominant Epitopes, Immunotherapy, Adoptive, Lymphocytes, Tumor-Infiltrating, Melanoma, Peptide Fragments, Protein Binding, Receptor, Melanocortin, Type 1, Skin Neoplasms, T-Lymphocytes, Cytotoxic.
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Are melanocortin 1 Receptor-derived peptides efficiently recognized by cytotoxic T lymphocytes from melanoma patients? Context: Melanocortin 1 Receptor (MC1R) is expressed in a majority of melanoma biopsies and cell lines. We previously demonstrated that three hydrophobic low-affinity HLA-A2-restricted MC1R-derived peptides: MC1R291-298, MC1R244-252 and MC1R283-291 can elicit cytotoxic T-lymphocytes (CTL) responses from normal donor peripheral blood lymphocytes (PBL). Moreover, peptide-specific CTL recognized a panel of MHC-matched melanomas, demonstrating that human melanoma cell lines naturally present MC1R epitopes. However, the natural presence of MC1R-specific T cells in melanoma patient's tumour and blood remains unknown. The presence of anti-MC1R specific CD8(+) T cells was established in a population of melanoma-specific T cells derived from peripheral blood mononuclear cells (PBMC) and tumour-infiltrating lymphocytes (TIL) from HLA-A2(+) melanoma patients. CTLs specific for the three MC1R-derived peptides that lysed allogeneic HLA-A2(+)MC1R(+) melanomas were elicited from PBMC, demonstrating the existence of an anti-MC1R T cell repertoire in melanoma patients. Moreover, TILs also recognized MC1R epitopes and HLA-A2(+) melanoma cell lines. Finally, HLA-A2/MC1R244-specific CD8(+) T cell clones derived from TILs and a subset of MC1R291 specific TILs were identified using HLA-A2/MC1R tetramers.
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Our results demonstrate that MC1R-derived peptides are common immunogenic epitopes for melanoma-specific CTLs and TILs, and may thus be useful for the development of anti-melanoma immunotherapy. Final Decision: yes