Abstract
An efficient cell culture and infection system for hepatitis C virus (HCV) is useful for analyzing the complete virus life cycle. Human hepatic Huh7.5.1 cells and a HCV-JFH1 strain have been widely employed for infection experiments. Huh7.5.1 cells that we have cultured exhibited heterogeneous phenotypes of HCV infection. By single-cell cloning of Huh7.5.1 cells, we isolated a clone highly permissive to HCV and a CD81-defective clone nonpermissive to HCV, designated as Huh7.5.1-8 and Huh7.5.1-5, respectively. Expression of CD81 into Huh7.5.1-5 cells restored the permissiveness to HCV, indicating that CD81 is essential for HCV infection and a defect in CD81 causes the nonpermissiveness to HCV in Huh7.5.1-5 cells. Huh7.5.1-8 cells had about 10-fold higher HCV replication activities, with cellular HCV RNA copy numbers of >109 copies/μg of cellular RNA and viral titers of >106 infectious units/ml of culture supernatant. Permissiveness of Huh7.5.1-8 cells to HCV infection was phenotypically very stable because there was no difference in permissiveness after more than 100 passages (1-year culture). This efficient cell culture system for HCV using Huh7.5.1-8 cells provides a powerful tool for studying the HCV life cycle and constructing antiviral strategies.
