Peptide‐specific ctl in tumor‐infiltrating lymphocytes from metastatic melanomas expressing mart‐1/melan‐a, gp100 and tyrosinase genes: A study in an unselected group of hla‐a2.1‐positive patients

Peptide specificity of cultured tumor‐infiltrating lymphocytes (TIL) was systematically investigated in a group of HLA‐A2.1+ metastatic melanoma patients consecutively referred to our department for surgical treatment. Seven samples from 6 patients were studied. All surgical specimens showed evidence of gp100, MART‐1/Melan‐A and Tyrosinose gene expression as detectable by reverse PCR (rPCR). Cultured TIL from 2 patients displayed cytotoxic activity against autologous or HLA‐matched EBV‐transformed cells previously pulsed with MART‐1/Melan‐A27‐35 peptide. In contrast, no CTL activity against gp 100280‐288 or tyrosinase1‐9 peptides could be observed. TIL were then repeatedly stimulated in vitro with the same peptides. After 6 restimulation courses at weekly intervals, specific recognition of gp100280‐288 and MART‐1/Melan‐A27‐35 peptides was detectable in 3 and 5 TIL populations, respectively. In one case Tyrosinase1‐9‐specific CTL could be demonstrated. Two TIL populations from metastases resected from a melanoma patient at 6 months' distance showed a different peptide specificity pattern, and no specific CTL could be generated from simultaneously sampled peripheral blood mononuclear cells (PBMC). All peptide‐specific CTL populations also displayed significant cytotoxic activity against HLA‐A2.1 matched melanoma cell lines expressing the antigens under investigation. Our data indicate that CTL specific for MART‐Melan‐A27‐35, gp100280‐288 or Tyrosinase1‐9 peptides could be expanded with varying frequency from TIL derived from 4 out of 6 HLA‐A2.1+ patients whose tumors expressed the genes encoding these tumor‐associated antigens (TAA). © 1995 Wiley‐Liss, Inc.