The majority of autologous cytolytic T-lymphocyte clones derived from peripheral blood lymphocytes of a melanoma patient recognize an antigenic peptide derived from gene Pme117/gp100

Anti-melanoma cytolytic T-lymphocyte (CTL) clones were derived from peripheral blood lymphocytes of HLA-A2 melanoma patient LB265 after stimulation with the autologous tumor cell line LB265-MEL, which showed high expression of melanocyte-lineage specific genes. Of 55 CTL clones, 46 recognized HLA-A2-restricted antigens, These 46 CTL clones were studied for their ability to specifically release tumor necrosis factor in the presence of COS cells cotransfected with the HLA-A2 gene and the cDNA of either tyrosinase, Melan-A/MART1, Pmel17/gp100, gp75/TRP1, or MSH receptor, Six CTL clones recognized the Melan-A/MART1 antigen, whereas the remaining 40 CTL clones recognized a Pme17/gp100 antigen, These 40 anti-Pme17/gp100 CTL clones were all able to lyse T2 cells pulsed with the antigenic peptide YLEPGPVTA, as previously reported, The T-cell receptor beta chain hypervariable region was sequenced and found to be identical in the 15 CTL clones analyzed, Taken together, these data show a high frequency of Pme117/gp100-specific T cells in autologous antitumor CTL clones derived from peripheral blood of a melanoma patient.