It is difficult to induce anti-tumor immunity in tumors with low antigenicity. In order to develop a more effective method of immunotherapy, we transfected interleukin-2 (IL-2), interleukin-4 (IL-4) and interleukin-6 (IL-6) genes into Lewis lung carcinoma (LLC) cells. Then, 1 x 10(6) LLC-IL-2, LLC-IL-4 or LLC-IL-6 cells were transplanted into C57BL/6 mice subcutaneously. All mice transplanted with LLC-IL2 and half those with LLC-IL-4 rejected the tumor cells. Survival time of LLC-IL-6 transplanted mice was significantly shorter than that of LLC transplanted mice, with no difference in tumor growth. These data suggest that transplantation of IL-2 or IL-4 gene transfected cells could effectively induce immunity against LLC. IL-6 transfection did not induce immunity, but induced cachexia.