Figure 1.

Different approaches to study hepatitis C virus (HCV) in animal models. First panel: animal species that can be experimentally infected with wild-type HCV (chimpanzee and tree shrew). Second panel: hepaciviruses and pegiviruses that infect animal species such as wild mice, rats, tamarins, bats, and horses. These viruses can be studied in their natural host, where they cause a HCV-like infection. Third panel: in vitro adaptation of HCV to mouse hepatocytes may allow the isolation of viral variants that can establish an infection in wild-type mice. Fourth panel: transient or stable expression of human factors that are essential to support infection of wild-type HCV or transgenic expression of viral proteins. Fifth panel: in xenotransplantation models, either the liver alone or both the liver and immune system are humanized.