[Hepatitis C virus].

Hepatitis C virus (HCV) is a small enveloped virus whose genome is a RNA molecule encoding a polyprotein that is processed by cellular and viral proteases to produce the 3 structural proteins (the core protein C and the 2 envelope proteins E1 and E2) and the 6 nonstructural proteins (NS2, NS3, NS4A, NS4B, NS5A and NS5B). The HCV genome exhibits a significant genetic heterogeneity. HCV isolates can be divided into genetically distinct groups referred to as genotypes, whereas the population of HCV genomes, within an infected individual, is present as a group of heterogeneous but closely related sequences referred to as quasi-species. Studies of the molecular biology of HCV and of new vaccinal or therapeutic strategies are hampered by the lack of easy to use cellular culture systems and of animal models.