T-CELL RECEPTOR USAGE BY CYTOTOXIC T-LYMPHOCYTES AGAINST AUTOLOGOUS HUMAN-MELANOMA

Background: T cell receptor (TCR) usage by tumor infiltrating lymphocy tes (TIL) represents the host's response to autologous melanoma (AM). The goal of this study is to determine TCR usage by cytotoxic T lympho cytes (CTL) against AM. Materials and Methods: CTL were generated from three patients using lymphocytes from metastatic or tumor-draining ly mph nodes by repeated in vitro sensitization (IVS). Total RNA was isol ated from CTL and reverse-transcribed to cDNA. TCR usage was determine d by polymerase chain I eaction (PCR) using TCR primers. Results: Cyto lytic activity was non-specific within the first 2-4 weeks following T VS and TCR repertoire in these cultures revealed random V alpha and V beta gene usage. In contrast, by 6-10 weeks of culture, cytolysis was specifically directed against AM cells and such specific cytolysis was significantly correlated with TCR Val (P<0.001). Conclusion: TCR Vol is associated with a common restricted melanoma antigen.