title: Frequent occurrence of high affinity T cells against MELOE-1 makes this antigen an attractive target for melanoma immunotherapy.
abstract: We recently showed that the infusion of tumor infiltrating lymphocytes specific for the MELOE-1 antigen was associated with a prolonged relapse-free survival for HLA-A2(+) melanoma patients who received tumor infiltrating lymphocytes therapy. Here, we characterized the MELOE-1/A2-specific T-cell repertoire in healthy donors and melanoma patients to further support an immunotherapy targeting this epitope. Using tetramer enrichment followed by multicolor staining, we found that MELOE-1-specific T cells were present in the blood of healthy donors and patients at similar frequencies (around 1 in 1x10(5) CD8(+) cells). These cells mainly displayed a naïve phenotype in 4/6 healthy donors and 3/6 patients, whereas high proportions of memory cells were observed in the remaining individuals of both groups. There was a recurrent usage of the Valpha12.1 chain for 17/18 MELOE-1-specific T-cell clones derived from healthy donors or patients, associated with diverse Vbeta chains and V(D)J junctional sequences. All clones derived from melanoma patients (9/9) were reactive against the MELOE-1(36-44) peptide and against HLA-A2(+) melanoma cell lines. This study documents the existence of a large TCR repertoire specific for the MELOE-1/A2 epitope and its capacity to give rise to antitumor CTL that supports the development of immunotherapies targeting this epitope.
authors.affiliation: UMR INSERM U892, CRCNA, Nantes, France.
authors.forename: Yann
authors.initials: Y
authors.lastname: Godet
authors.forename: Juliette
authors.initials: J
authors.lastname: Desfrançois
authors.forename: Virginie
authors.initials: V
authors.lastname: Vignard
authors.forename: Dirk
authors.initials: D
authors.lastname: Schadendorf
authors.forename: Amir
authors.initials: A
authors.lastname: Khammari
authors.forename: Brigitte
authors.initials: B
authors.lastname: Dreno
authors.forename: Francine
authors.initials: F
authors.lastname: Jotereau
authors.forename: Nathalie
authors.initials: N
authors.lastname: Labarrière
mesh_terms: D000951:Antigens, Neoplasm / Q000276:immunology*; D002454:Cell Differentiation / Q000276:immunology; D002469:Cell Separation; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D005434:Flow Cytometry; D006801:Humans; D007167:Immunotherapy / Q000379:methods*; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology; D008545:Melanoma / Q000276:immunology* / Q000628:therapy; D009363:Neoplasm Proteins / Q000276:immunology*; D010641:Phenotype; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
chemical_list: D000951:Antigens, Neoplasm; D018984:Epitopes, T-Lymphocyte; C533520:MELOE-1 antigen, human; D009363:Neoplasm Proteins; D011948:Receptors, Antigen, T-Cell