Enhancement of suppressor cell generation in human mixed lymphocyte cultures by interferon

Mixed lymphocyte culture (MLC) interactions are differentially influenced by interferon: proliferation is reduced whereas the induction of allospecific cytotoxic cells is enhanced. The experiments presented here show that interferon also potentiates the induction of cells which suppress the MLC responsiveness of freshly prepared responding cells from the same donor. This effect is most evident when low doses of interferon and low numbers of suppressor cells are used, and it does not seem to be exerted by a cytotoxic mechanism. Maximum effect was seen with interferon present from the beginning of and throughout the induction period, and once the suppressor cells were generated, interferon did not further potentiate their function.