Monitoring the antiviral effect of alpha interferon on individual cells

An infectious hepatitis C virus (HCV) cDNA clone (JFH1) was generated recently. However, quantitative analysis of HCV infection and observation of infected cells have proved to be difficult because the yield of HCV in cell cultures is fairly low. We generated infectious HCV clones containing the convenient reporters green fluorescent protein (GFP) and Renilla luciferase in the NS5a-coding sequence. The new viruses responded to antiviral agents in a dose-dependent manner. Responses of individual cells containing HCV to alpha interferon (IFN-alpha) were monitored using GFP-tagged HCV and time-lapse confocal microscopy. Marked variations in the response to IFN-alpha were observed among HCV-containing cells.