Experimental Study On Tumor Immunity Of Hepatocarcinoma Cells Induced By IL-12,IFN-γ Synergizes B7-1 Costimulation

Objective: To observe the effects of IFN- Y and IL-12 on the B7-I expression of B7-1 transfected liver cancer cells (HepG2/B7-l). Study the ability of IL-2 , IFN-r production in T cells induced by B7-1 transfected HepG2. Investigate the capability of B7-1 costimulatory molecule alone or combined with IFN-r /IL-12 in inducing T lymphocytes activation in vitro. Evaluate the effects of B7-1 molecule combined with IFN-r /IL-12 in the primary cytolytic activity against HHCC.Method: Collect HepG2 cell and HepG2/B7-l transfected via retroreverviral transduction, inspect the respective expressing of B7-1 costimulatory molecules by flow cytometric(FCM) after treated with IFN-r IL-12. ELISA techniques were used to assay the production of IFN-r and IL-12. lymphocyto proliferation was evaluated by MTT assay. Use LDH releasing test to check the cytotoxic activity of CTL.Results: FCM revealed the B7-1 molecule expressing on the HepG2 cell surface, however, the level of B7-1 was very lower and its positive rate was 6.30 %.B7-1 molecule expressing on the HepG2/B7-1 cell surface was strongly (positive rate: 83.6%).After treatment with IL-12 and IFN- r, the expressing of B7-1 on HepG2/B7-1 cell surface increase 92.6% and 90.2%, respectively. HepG2/B7-l cell increased the production of IL-2 and IFN-r , and in further step when combining with IL-12 or IFN-r, can induce the synthesis of IL-12, IFN-r . The abovecombination promotes the proliferation of lymph-cells. There is a distinct accretion comparing with HepG2 group. Meanwhile, contradistinguishing from the discrepancy of the counterpart group, the cytotoxic activity of CTL against HepG2/B7-l cells were greatly improved in the above group with two combinations. P<0.05Conclusion: 1.IL-12 and IFN-r increase the B7-1 expressing of the transfected B7-1 hepatocellular carcinoma cell respectively. IL-12 and IFN-r improve the production of IL-2 and IFN- y when induced by the transfected hepatocellular carcinoma cell (HepG2/B7-1).2.IL-12 IFN-r may affect their activation on T cell by adjusting the biological activity of B7-1 molecule.3.B7-1 gene transfer combining with IL-12 or IFN-r greatly promotes the proliferation of lymph-cells, improves the cytotoxic activity of CTL on liver cancer cell, and claims the association between them.