PEPTIDE-SPECIFIC CTL IN TUMOR-INFILTRATING LYMPHOCYTES FROM METASTATIC MELANOMAS EXPRESSING MART-I 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) w as systematically investigated in a group of HLA-A2.1(+) metastatic me lanoma patients consecutively referred to our department for surgical treatment. Seven samples from 6 patients were studied. All surgical sp ecimens showed evidence of gp100, MART-1/Melan-A and Tyrosinose gene e xpression as detectable by reverse PCR(rPCR). Cultured TIL from 2 pati ents displayed cytotoxic activity against autologous or HLA-matched EB V-transformed cells previously pulsed with MART-1/Melan-A(27-35) pepti de. In contrast, no CTL activity against gp 100(280-288) or tyrosinase (1-9) peptides could be observed. TIL were then repeatedly stimulated in vitro with the same peptides. After 6 restimulation courses at week ly intervals, specific recognition of gp 100(280-288) and MART-1/Melan -A(27-35) peptides was detectable in 3 and 5 TIL populations, respecti vely. In one case Tyrosinase(1-9)-specific CTL could be demonstrated. Two TIL populations from metastases resected from a melanoma patient a t 6 months' distance showed a different peptide specificity pattern, a nd no specific CTL could be generated from simultaneously sampled peri pheral blood mononuclear cells (PBMC). All peptide-specific CTL popula tions also displayed significant cytotoxic activity against HLA-A2.1 m atched melanoma cell lines expressing the antigens under investigation . Our data indicate that CTL specific for MART-Melan-A(27-35), gp100(2 80-288) or Tyrosinase(1-9) peptides could be expanded with varying fre quency from TIL derived from 4 out of 6 HLA-A2.1(+) patients whose tum ors expressed the genes encoding these tumor-associated antigens (TAA) . (C) 1995 Wiley-Liss, Inc.