RESUMEN
Objective To investigate the effect of Intedeukin-18 (IL-18) on Th1/Th2 balance and its antitumor mechanism in C57BL/6 mice Lewis lung cancer model. Methods 24 C57BL/6 mice were randomly divided into three equal groups: group A(IL-18 injec-tion group, n = 8), group B (Lewis lung cancer model, n = 8) and group C (normal control group, n = 8). The Lewis lung cancer cells were cultured and implanted subcutaneously into the group A and group B. IL-18 and NS were given to group A and B respectively by intrap-eritoneal injection on the 7th day (once every day, 7 times altogether), but group C was not given any treatment. Enzyme-linked immunosor-bent assay (ELISA) was used to detect the Th1/Th2 cytokines. Health status in all the animals was evaluated; the volume and weight ofsubcutaneous tumors were measured. Results The concentration of IFN-γ in group A and C were significantly higher than those in group B (P <0.05), and the concentration of IL-4 in group A and C were significantly lower than those in group B (P<0.05), but there was no significant difference between group A and C (P>0.05). The tumor growth inhibitory rate was 75%. Conclusion IL-18 can effectively induced IFN-γ and inhibit IL-4 production, regulate Th1/Th2 balance in the C57BL/6 mice Lewis lung cancer model, and elicit the antitu-mor immunity of the host, which could obviously inhibit the growth of tumor cells and decelerate the proliferation of tumor cells.