Antitumor Immune Response Of MHC Class Ⅰ Chain-related Gene A Modified Oral Squamous Cell Carcinoma Vaccine: An Experimental Study In Mice

ObjectiveTo investigate the inhibition effect of tumor growing and the potency of MHC class I chain-related gene A (MICA) modified oral squamous cell carcinoma cells vaccine to bearing tumor SCID mice.MethodsHu-PBL was separated by density gradient centrifugation method, and then was injected into abdominal cavity of SCID mice whose hematopoietic function of bone marrow was inhibited by Cyclophosphamide to build the hu-PBL/SCID model. Then the level of human IgG in the sera of hu-PBL/SCID mice was detected with ELISA Kit to judge the effect of immunologic reconstruction.The Tb-pEGFP-N1-MICA cells transfected the pEGFP-N1-MICA plasmid and overexpressed MICA were irradiated with 60Co radioactive source in fatal dose to prepare the inactivated tumor cell vaccine, the cells transfected blank plasmid and no transfection were irradiated as control. Then the vaccine was injected into abdominal cavity of SCID mice to reconstruct the immunologic function. Two weeks later, the tumor bearing hu-PBL/SCID model was establish by subcutaneous injection of the Tca8113-Tb cells, then the growth of tumor was observed, the volume and weight of tumor was measured to research the inhibition of tumor with tumor cell vaccine. And the rate of tumour inhibition was calculated.The expression of NKG2D and the cytotoxicity in vitro to Tb cells of peripheral blood mononuclear cells (PBMCs) and spleen cells were measured by flow cytometry and lactate dehydrogenase (LDH) release assay.The data was analyzed with SPSS 16.0 software package,it is significant when P<0.05. Results1. Human IgG can be detected in mice's peripheral sera one week after the the hu-PBL/SCID model was built,and it kept rising in 5 weeks.2. The tumor mass could be touched in all of the Hu-PBL/SCID mice after inoculating the inactivated vaccine,the tumor formation rate is 100%. Compared with the Tca8113-Tb and the Tb-pEGFP-N1 group,the volume and weight of transplantable tumor in Tb-pEGFP-N1-MICA group decreased obviously (P<0.05).The rate of tumour inhibition is 63.26%.3. The results of flow cytometry and LDH release assay suggested that the expression of NKG2D and the cytotoxicity in Tb-pEGFP-N1-MICA group was higer than that of the Tb and Tb-pEGFP-N1 group, the differences was statically significant (P<0.05)Conclusion1. After injecting 0.2mL Hu-PBL the density of which is 2.5×108/mL, into abdominal cavity of SCID mice,human IgG can be detected in its peripheral sera and it kept rising, suggested that we successed to establish the hu-PBL/SCID model.2. The MICA gene modified oral squamous cell carcinoma vaccine can enhance the ability of antitumor immune response. The mechanism may be up-regulated NKG2D and promoted the proliferation,then improved its cytotoxicity effect in tumor target cells.