Characterization of interleukin 2 (IL-2)-dependent cytotoxic T-cell clones: V. Transfer of resistance to allografts and tumor grafts requires exogenous IL-2

Abstract

The adoptive transfer of resistance to tumor grafts with cloned interleukin 2 (IL-2)-dependent cytotoxic T-cell lines was examined. Two clones were used: clone CTLL-A2 which recognizes H-2D d determinants and clone CTLL-R5 which recognizes a unique cell surface antigen of BALB/c leukemia RL♂ol. Systemic transfer of resistance with these clones was accomplished only when exogenous (rat or human) IL-2 was administered at the same time. Intraperitoneal injection of CTLL-A2 cells accelerated rejection of sarcoma Meth A (H-2D d), but not ascites sarcoma BP8 (H-2 k) or leukemia EL4 (H-2 b) inoculated subcutaneously into C57BL/6 mice. CTLL-R5 cells were examined in local (Winn tests) as well as systemic transfer experiments. When mixed with leukemia cells before subcutaneous injection, they suppressed the growth of leukemia RL♂ol without exogenous IL-2. When injected intraperitoneally, CTLL-R5 cells inhibited the growth of subcutaneous grafts of leukemia RL♂ol only when exogenous IL-2 was administered at the same time. CTLL-R5 did not inhibit the growth of other radiation-induced BALB/c leukemias.