Augmentation of recombinant interleukin-2-dependent murine macrophage-mediated tumour cytotoxicity by recombinant tumour necrosis factor-alpha.

The activation of murine macrophages by recombinant human interleukin-2 (rH-IL-2) alone or in combination with recombinant human tumour necrosis factor-alpha (rH-TNF) was studied. Mouse peritoneal exudate macrophages were activated in vitro to the tumouricidal state. Macrophage treatment with rH-IL-2 alone slightly enhanced cytotoxic activity against B16 melanoma cells. Synergism was observed when macrophages were treated with rH-IL-2 and rH-TNF, either when applied sequentially or when both agents were given at the same time.