ENHANCED EXPRESSION OF HLA CLASS-I MOLECULES IN HUMAN HEPATOCELLULAR-CARCINOMA CELLS TRANSDUCED WITH GAMMA-INTERFERON GENE

Objective To investigate the expression of exogenous gamma-interferon gene in human hepatocellular carcinoma cells following retroviral tran sduction and the effect on the expression of surface HLA class I molec ules. Methods Retroviral vector pLXSN was used to introduce human gamm a-interferon (IFN-gamma) gene into four different human hepatocellular carcinoma cell lines (HCC). The G418-resistant colonies were isolated and cloned. The integration and expression of IFN-gamma gene were det ermined by PCR and RT-PCR analysis. A bioassay method was used to test the amount of IFN-gamma secreted by gene modified HCC cells. The expr ession of HLA class I molecules in HCC cells were analyzed by flow cyt ometry using indirect fluorescence staining. Results Four different HC C cell lines were successfully transduced with human IFN-gamma gene us ing retroviral vector. The integration and expression of IFN-gamma gen e were shown only in the transduced cells. All four genetically modifi ed HCC cells can secrete varied amount of IFN-gamma and demonstrate a significant upregulation of surface HLA class I antigens. One specific HLA class I antigen, HLA-A2, has almost the same degree of increase a s that of the total HLA class I molecules after transduction with IFN- gamma gene. Conclusions Gene modification with IFN-gamma gene can sign ificantly enhance the expression of HLA class I molecules in HCC cells and may increase its immunogenicity. These gene modified tumor vaccin es can be helpful in tumor biotherapy.