Expression And Identification Of Human CD80-IgG1Fc Fusion Protein And Its Induced Anti-tumor Effects

Objective: To construct the human CD80-IgG1Fc fusion protein expression vector,which was transfected into CHO cells to establish a stable expression strain. Then investigate the effect on anti-tumor immune response in vitro with fusion protein modified H22 cells and on the tumor growth of mouse cancer model by subcutaneously transplanted modified cells.Methods: The genes of CD80 extracellular domain and IgG1Fc were amplified from human PBMC by RT-PCR, the recombinant CD80-IgG1Fc/pcDNA3.1 (+) were constructed and transfected into CHO cells. The CHO transfectants were screened for stable expression of the fusion protein which was detected by RT-PCR, Western blot and ELISA. The mouse liver cancer cell line H22 was modified with fusion protein and CD80 was detected by flow cytometry. The effect of modified H22 on lymphocyte proliferation and its cytotoxicity were measured by MTT assay and phosphate dehydrogenase release test. For further monitoring the tumor growth in vivo, the mouse cancer model with H22 cells was established by subcutaneously transplanted, then inoculated with fusion protein-modified H22 cells.Results: The expression vector, CD80-IgG1Fc/pcDNA3.1 (+), was constructed successfully and a stable expression strain of CHO cells was obtained. After fusion protein modification, H22 cells enhanced the lymphocyte proliferation remarkably in the experimental group compared with that of the control,as same as CTL cytotoxicity. The size of subcutaneous tumor in the mouse model was smaller at the experimental group at day 12 then the control group respectively.Conclusion: CD80-IgG1Fc fusion protein was stably expressed in the CHO cells. Fusion protein-modified H22 cells could remarkably enhanced lymphocyte proliferation and CTL cytotoxicity in vitro. The fusion protein could induced anti-tumor immune response and inhibit tumor growth in vivo.