Hepatitis C virus replication in transfected and serum-infected cultured human fetal hepatocytes

Understanding the pathogenesis of hepatitis C requires the availability of tissue culture models that sustain viral replication and produce infectious particles. We report on the establishment of a culture system of nontransformed human fetal hepatocytes that supports hepatitis C virus (HCV) replication after transfection with full-length in vitro-transcribed genotype 1a HCV RNA without adaptive mutations and infection with patient sera of diverse HCV genotypes. Transfected and infected hepatocytes expressed HCV core protein and HCV negative-strand RNA. For at least 2 months, transfected or infected cultures released HCV into the medium at high levels and usually with a cyclical pattern. Viral replication had some cytotoxic effects on the cells, which produced interferon (IFN)-beta as a component of the antiviral response. Medium from transfected cells was able to infect naïve cultures in a Transwell system, and the infection was blocked by IFN-alpha and IFN-lambda. Viral particles analyzed by sucrose density centrifugation had a density of 1.17 g/ml. Immunogold labeling with antibody against HCV envelope protein E2 decorated the surface of the viral particles, as visualized by electron microscopy. This culture system may be used to study the responses of nontransformed human hepatocytes to HCV infection, to analyze serum infectivity, and to clone novel HCVs from infected patients.