A novel cell culture model reveals the viral interference during hepatitis B and C virus coinfection

Coinfection of hepatitis B virus (HBV) and hepatitis C virus (HCV) may result in severe liver disease and frequent progression to cirrhosis and hepatocellular carcinoma. Clinical evidence suggests that HBV replication is suppressed by replicating HCV and often rebounds after treatment with drugs against HCV. Thus, a highly efficient cell culture system permissive for HBV/HCV would facilitate investigation on the interaction and pathogenesis after coinfection. Here we reported a robust HBV/HCV coinfection cell culture model by overexpressing human sodium-taurocholate cotransporting polypeptide (NTCP), CD81 and Mir122 into HepG2 cells and investigated interactions between HBV and HCV. In this system, HepG2-NTCP/CD81/Mir122 cells not only supported robust infection and replication of HBV and HCV, but also allowed HBV/HCV coinfection in the single cell level. Our result showed cells with replicating HBV still supported HCV infection. However, HBV replication was suppressed by HCV through the inhibition of HBV core promoter and S promoter II activity, and this inhibition was attenuated by the interferon alpha (IFNa) treatment, suggesting HCV influence on HBV at transcriptional level. Coinfection of HBV/HCV in this system did not block IFN stimulated genes expression. Inhibition of HCV by direct-acting antiviral drugs restored HBV replication and expression of viral genes. Conclusions: HepG2-NTCP/ CD81/Mir122 fully supports HBV/HCV coinfection, replication and interaction. This novel cell model offers a platform to advance our understanding of the molecular details of the interaction, pathogenesis and outcomes of HBV/HCV coinfection.