Systemic administration of IL-2 induces lymphokine-activated killer (LAK) cells capable of killing macrophages in various tissues.

Murine lymphokine-activated killer (LAK) cells induced by systemic high-dose recombinant human interleukin 2 (IL-2) administration lysed fresh syngeneic peritoneal macrophages (M phi). LAK cells lysed resident peritoneal M phi and M phi activated in vivo with thioglycollate (TG), Corynebacterium parvum (C. parvum), or Bacillus Calmette-Guérin (BCG). The induction of anti-M phi cytolytic activity was seen in the spleen, liver, lung, lymph nodes and peritoneal cavity, but was not observed in the thymus. Fluorescence analysis revealed that the majority of infiltrated cells in the peritoneal cavity of IL-2-administered mice were Thy-1+, asialo GM1+, L3T4-, Ly2-. Surface marker analysis on peritoneal exudate cells (PEC) from IL-2-administered mice with depletion techniques using antibody (Ab) and complement (C) indicated that Thy-1+, asialo GM1+, L3T4-, Ly 2- cells were responsible for anti-M phi lysis. These studies indicate that the in vivo administration of IL-2 induces LAK cells capable of killing M phi in various tissues.