Interleukin 4 (B cell stimulatory factor 1) can mediate the induction of lymphokine-activated killer cell activity directed against fresh tumor cells

Interleukin 4 (IL-4) expresses multiple biologic activities, including B cell, mast cell, and T cell stimulation. We showed that the incubation of resting splenocytes from C57BL/6 mice solely in purified native or recombinant mouse IL-4 results in the generation of lymphokine-activated killer (LAK) activity directed against fresh, syngeneic sarcoma cells. The precursor activated by IL-4 expresses surface asialo-GM1. In addition, IL-4 is capable of amplifying the splenic LAK activity induced by recombinant IL-2. The generation, by IL-4, of killer cells with broad antitumor reactivity raises the possibility of using IL-4 alone or in combination with IL-2 in the immunotherapy of cancer in animal models.