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 transduction and the effect on the expression of surface HLA class I molecules.
Methods: Retroviral vector pLXSN was used to introduce human gamma-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 determined 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 expression of HLA class I molecules in HCC cells were analyzed by flow cytometry using indirect fluorescence staining.
Results: Four different HCC cell lines were successfully transduced with human IFN-gamma gene using retroviral vector. The integration and expression of IFN-gamma gene were shown only in the transduced cells. All four genetically modified HCC cells can secrete varied amount of IFN-gamma and demonstrate a significant up-regulation of surface HLA class I antigens. One specific HLA class I antigen, HLA-A2, has almost the same degree of increase as that of the total HLA class I molecules after transduction with IFN-gamma gene.
Conclusions: Gene modification with IFN-gamma gene can significantly enhance the expression of HLA class I molecules in HCC cells and may increase its immunogenicity. These gene modified tumor vaccines can be helpful in tumor biotherapy.