On November 13, Journal of Virology published a research article online entitled “A novel strategy to develop robust infectious hepatitis C virus cell culture system directly from a clinical isolate”. This work was accomplished by Dr. Jin Zhong’s group at Institut Pasteur of Shanghai, Chinese Academy of Sciences.
Hepatitis C virus infection is one of the leading causes of chronic hepatitis and may lead to cirrhosis and hepatocellular carcinoma. The cell culture model of HCV infection plays a pivotal role in the studies of HCV biology, antiviral agents and vaccine development. In 2005, the establishment of JFH-1-based HCV cell culture system has greatly facilitated the research progress in the HCV field. The RNA genome of HCV is highly heterogeneous, and HCV of different genotypes respond differently to the antiviral treatment. Moreover, HCV genotype is an important prognosis factor for pathogenesis of HCV-associated diseases. Thus, it necessitates the development of more HCV cell culture systems derived from different virus strains. The biggest challenge is to construct a cDNA clone that would allow for the production of infectious HCV virions in cell culture.
Jie Lu, the first author of this article, collaborating with her coworkers in the lab, developed a full-length infectious cDNA clone, named PR63cc, from a genotype 2a HCV isolate through a functional selection protocol and cell culture adaptation. PR63cc could efficiently produce infectious viruses in hepatoma derived cell lines. Remarkably, PR63cc virus displays a distinct sensitivity to the existing anti-HCV drugs from JFH-1 virus, highlighting the importance of developing cell culture model from various clinical isolates.
PR63cc is the first infectious cDNA clone originated from Chinese hepatits C patient serum, and is also the first infectious clone which is constructed directly from clinical isolates without constructing a consensus sequence of viral genome. This novel strategy can be applied to constructing more infectious cDNA clones from other clinical HCV isolates, with potential implications for individualized treatments of HCV patients. Importantly, the patent to cover the methodology, cDNA clone and virus described in this study has been filed, paving a way for the anti-HCV drug and vaccine development.
This work was conducted in collaboration with Dr. Qing Xie’s group in Ruijin Hospital, affiliated with Shanghai Jiaotong University, and supported by grants from the Chinese National 973 Program and Chinese National Key Programs on Infectious Diseases.
Characterization of PR63cc virus. (A) PR63cc can infect Huh7.5.1 cells. Nuclei stained in blue, HCV E2 protein stained in red. (B) Both JFH-1 and PR63cc could propagate efficiently in Huh7.5.1 cells. (C) Efficacy of HCV NS5A inhbibitor daclatasvir against JFH-1, PR63cc and PR63cc-NS5A-M31L.