Impaired antiviral activity of interferon alpha against hepatitis C virus 2a in Huh-7 cells with a defective Jak-Stat pathway | Hazari et al. Virology Journal 2010 7 36 http content 7 1 36 VIROLOGY JOURNAL RESEARCH Open Access Impaired antiviral activity of interferon alpha against hepatitis C virus 2a in Huh-7 cells with a defective Jak-Stat pathway 1 11 12 3 Sidhartha Hazari Partha K Chandra Bret Poat Sibnarayan Datta Robert F Garry Timothy P Foster Gus Kousoulas3 Takaji Wakita4 Srikanta Dash1 Abstract Background The sustained virological response to interferon-alpha IFN-a in individuals infected with hepatitis C virus HCV genotype 1 is only 50 but is about 80 in patients infected with genotype 2-6 viruses. The molecular mechanisms explaining the differences in IFN-a responsiveness between HCV 1 and other genotypes have not been elucidated. Results Virus and host cellular factors contributing to IFN responsiveness were analyzed using a green fluorescence protein GFP based replication system of HCV 2a and Huh-7 cell clones that either possesses or lack a functional Jak-Stat pathway. The GFP gene was inserted into the C-terminal non-structural protein 5A of HCV 2a full-length and sub-genomic clones. Both HCV clones replicated to a high level in Huh-7 cells and could be visualized by either fluorescence microscopy or flow cytometric analysis. Huh-7 cells transfected with the GFP tagged HCV 2a genome produced infectious virus particles and the replication of fluorescence virus particles was demonstrated in naive cells after infection. IFN-a effectively inhibited the replication of full-length as well as sub-genomic HCV 2a clones in Huh-7 cells with a functional Jak-Stat pathway. However the antiviral effect of IFN-a against HCV 2a virus was not observed in Huh-7 cell clones with a defect in Jak-Stat signaling. HCV infection or replication did not alter IFN-a induced Stat phosphorylation or ISRE promoter-luciferase activity in both the sensitive and resistant Huh-7 cell clones. Conclusions The cellular Jak-Stat pathway is critical for a successful IFN-a antiviral .
