INTERLEUKIN-12 AUGMENTS THE GENERATION OF AUTOLOGOUS TUMOR-REACTIVE CD8(-LYMPHOCYTES FROM TUMOR-INFILTRATING LYMPHOCYTES() CYTOTOXIC T)

Human tumor-infiltrating lymphocytes (TIL) were obtained from breast c ancer, renal cancer or neuroblastoma to investigate the generation of autologous tumor-reactive CD8(+) cytotoxic T lymphocytes (CTL). When T IL were cultured with interleukin (IL)-2 (100 U/ml), the growth of TIL peaked around 8-10 days after the initiation of culture. In contrast, the proliferation of TIL cultured with IL-2 plus IL-12 peaked around 4-5 days after culture and tumor cells rapidly disappeared from the cu lture. To determine the generation of autologous tumor-reactive CD8(+) CTL, TIL-derived CD8(+) T cells were separated by FACStar. Both IL-2- activated and IL-2 plus IL-12-activated TIL-CD8(+) T cells showed the same level of lymphokine-activated killer activity against a variety o f tumor cells. However, TIL-CD8(+) T cells activated with IL-2 plus IL -12 revealed greatly augmented cytotoxicity against autologous tumor c ells compared with that induced by IL-2 alone. The autologous tumor ce ll-killing activity of TIL-CD8(+) CTL was significantly inhibited by t he addition of F(ab)(2) anti-CD3 monoclonal antibody, indicating that these CTL recognize autologous tumor antigen through T cell receptor. These results imply that IL-12 is a novel cytokine which facilitates t he generation of autologous tumor-reactive CD8(+) CTL from TIL.