[Tumor-infiltrating lymphocytes from human metastatic melanoma]

Tumor-infiltrating lymphocytes (TIL) were isolated from human metastatic melanoma and were characterized. These TIL were predominantly CD 3+ (Leu 4+) CD 4- (Leu 3a-) CD 8+ (Leu 2a+) T lymphocytes. Ten to twenty percent of these TIL had the ability to bind to autologous tumor cells. None of these cells were cytotoxic against autologous tumor cells as judged by trypan blue exclusion test either prior to culture or after a 1-day incubation in vitro. Addition of recombinant interleukin 2 (rIL 2) to the culture induced proliferation and differentiation of TIL into cytotoxic T lymphocytes (CTL) against non cultured autologous tumor targets. These results suggest that TIL may consist of precursor CTL or immature CTL.