ANTITUMOR IMMUNITY AND VACCINE EFFECT INDUCED BY IL-12 SYNERGIZES B7-1 GENE TRANSFECTED CELLS

Objective: To study the synergic effects of IL-12 and B7-1 transfectant on antitumor immunity in vivo. Methods: The retrovirus vector encoding mIL-12 and mB7-1 gene was tranfected into EL-4 thymic lymphoma cells respectively.The cells were used as tumor vaccine and the therapeutic effect was observed. Results: In contrast to the miceimmunized with EL-4/Wt or EL-4/Neo groups, thetumorigenicity of EL-4/IL-12 transfectant was decreased(P<0.001). The EL-4/IL-12 and EL-4/B7-1 cells irradiatedwith 60Co showed significant systematic protective effectsagainst the rechallenge of EL-4/Wt. 60Co irradiatedEL-4/IL-12 cells delayed the occurrence of tumor andprolonged the survival period of tumor bearing mice.Combination of the vaccines of EL-4/IL-12 and EL-4/B7-1 resulted in the enhanced therapeutic effect compared witheach single transfectant group (P<0.001). Conclusion: The results showed that IL-12 transduced cells could enhancethe antitumor immunity of host as cancer vaccine.Combination of the EL-4/IL-12 and EL-4/B7-1 transfectant could improve immunity of host and is a prospect cancervaccine.