from Takaji Wakita writing in Hepatitis C: Antiviral Drug Discovery and Development:
Hepatitis C virus (HCV) infection causes chronic liver disease and is a health problem worldwide. Recent rapid progress in HCV research has been largely dependent on the development of an HCV culture system and infectious small animal model. The most important part of the HCV infection system is the discovery of the JFH-1 clone isolated from a fulminant hepatitis C patient. The JFH-1strain fits into the cluster of genotype 2a, and its viral genome sequence is monoclonal. The JFH-1 strain replicates efficiently in cultured cell lines without acquiring adaptive mutations, and it secretes infectious viral particles into culture medium. This infectious HCV system provides for the first time a powerful tool to study the viral life cycle, construct anti-viral strategies and develop effective vaccines.
Further reading: Hepatitis C: Antiviral Drug Discovery and Development