Specific cytotoxicity against autologous tumour and proliferative responses of human lymphocytes grown in interleukin 2.

Peripheral blood lymphocytes of cancer patients were sensitized in vitro to autologous tumour cells in mixed lymphocyte-tumour culture (MLTC). Blast cells were isolated on discontinuous Percoll gradients from MLTC which showed significant stimulation of [3H]-thymidine incorporation. Cultured T cells (CTC) were derived from these blasts by growth in conditioned medium containing interleukin-2 (IL-2) and maintained for up to 51 days by repeated feeding with IL-2 and in some cases by addition of irradiated allogeneic blood mononuclear cells as "fillers". These cultures showed specific cytotoxic reactivity against autologous tumour and in only a few cases was natural killing (NK) of K562 cells apparent. Restimulation of CTC with tumour was measured in primed lymphocyte test (PLT). Increased uptake of [3H]-thymidine was found upon stimulation by autologous tumour and allogeneic tumour of the same site and histology but there was no response to non-related tumours or to a panel of allogeneic lymphocytes. No sensitization to autologous HLA-D/DR could be detected by restimulation or cytotoxicity against monocytes in the majority of cases. These data suggest that, by careful selection of sensitised blasts from MLTC, it is possible to obtain CTC with both helper (proliferative) and cytotoxic T cells and that such CTC have specific reactivity against tumour cells. These cellular reagents will be useful in defining the antigenicity of human neoplasms and possibly in therapy.