Objective: To investigate the possible influence of HBV and its antigens on the expressions of JAK-STAT signal transduction pathway molecules and the antiviral proteins of IFN alpha.
Methods: The HepG2 cells were transfected with pSM2, pHBS2-S and pHBc-EGFP plasmids which express HBV whole particles or S-antigen, Pre-S antigen and core antigens. The infectious supernatant from HepG2.2.15 cells and the pured HBV proteins which contained the S, Pre-S antigens were used to treat the HepG2 cells. Northern blot and RT-PCR were applied to analyse the expressions of the antiviral proteins MxA, 2' -5' OAS, 9-27 and the JAK-STAT signal transduction pathway molecules STAT1 in HepG2 cells responded to the IFN alpha treatment.
Results: The HepG2 cells transfected with pSM2, pHBS2-S and pHBc-EGFP plasmids could express whole HBV particles and HBsAg, Pre-S antigen and HBcAg. The quantitation of expressed HBV particles and antigens increased significantly during the course of transfection. Northern blot hybridization analysis indicated that the HepG2 cells expressed IFN alpha antiviral proteins MxA, 2' -5' OAS and 9-27. When transfected with pHBV-dimer, pHBS2-S, pHBc-EGFP plasmids, the IFN/A antiviral proteins MxA, 2' -5' OAS and 9-27 in transfected cells were reduced greatly as compared to the un-transfected HepG2 cells, and the expressed antiviral proteins decreased sharply with the development of transfection time. Furthermore, the expression of IFN alpha JAK-STAT signal transduction pathway molecule STAT1 was also inhibited with the expression of HBV particles and HBV antigens in transfected HepG2 cells.
Conclusions: The HBV and its antigens influence the expressions of IFN alpha JAK-STAT signal transduction pathway molecules and antiviral proteins in the hepatocellular models in vitro. It is indicated that HBV might possess the activity to antagonise or counteract the IFN alpha antiviral action.