[Virology of hepatitis C virus].

Hepatitis C virus (HCV) along with hepatitis G virus are members of the hepacivirus genus of the flavi-viridae family to which the flavi- and pestis viruses also belong. The HCV genome has only one ORF which is flanked by a 5' and 3' noncoding region. The ORF encodes for a single polyprotein, which is stepwise cleaved into the 3 structural proteins, core (C), envelope 1 and 2 (E1,2) as well as into 7 non-structural proteins (p7, NS2, NS3, NS4A, NS4B, NS5A, NS5B). The proteolytic active NS3 plays a central role in this processing. Whereas expectations for development of an HCV vaccine are not very optimistic today, there is great hope in new therapeutic possibilities by inhibition of NS3 function. HCV is highly variable. In the liver and serum of a single patient, genetically slightly different virus particles (quasispecies) can be found. Worldwide, hepatitis C virus has been classified into genotypes and subtypes. This differentiation is not only important epidemiologically, but also has biological and therapeutical implications.