Anti-tumor Mechanism Of Dendritic Cells From Mouse Bone Marrow Monocytes Induced By OK-432 Combined With Freeze-thaw Tumor Cell Lysates

Objective:To prepare the anti-tumor vaccine of dendritic cells from mouse bone marrow monocytes induced by OK-432 combined with freeze-thaw tumor cell lysates. The IL-12 amounts secreted by the DCs were determined in vitro. The anti-tumor role of the DCs vaccine was observed in forestomach carcinoma-bearing mice and the anti-tumor mechanisms of the vaccine were discussed.Methods: The monocytes of mouse bone marrow (BMMCs) were isolated by adherence method and cultured in RPMI1640 containing 10% FCS, rmGM-CSF and rmIL-4 and then the cells were loaded with freeze-thaw cell lysates of mouse forestomach carcinoma and stimulated by OK-432 so as to control the maturation of DCs in vivo .The DCs were observed by the optical microscope and the electron microscope. The IL-12 amounts in the supernatant were detected by ELISA technique. The DCs vaccines were injected into the mice bearing forestomach carcinoma through the caudal vein. The tumor and spleen weights were weighted. RT-PCR , ELISA and immunohistochemical techniques were used to detect IL-12 mRNA, the IL-12 level and VEGF level in the tumor tissue.Results: The DCs induced by OK-432 combined with freeze-thaw tumor cell lysates showed typical morphology and secreted high level of IL-12. High level of IL-12 was also found and VEGF was reduced in the tumor tissue after infusion of the DCs. OK-DCs group showed more effective on the tumor inhibition in vivo than other groups.Conclusion: The DCs induced by OK-432 combined with freeze-thaw tumor cell lysates can effectively inhibit the growth of forestomach carcinoma in mice. The anti-tumor mechanisms of the DCs infusion were associated with the inhibition of which was controlled by the increasing IL-12 due to DCs.