title: Interferons alpha, beta, gamma each inhibit hepatitis C virus replication at the level of internal ribosome entry site-mediated translation.
abstract: Interferon (IFN)-alpha is the standard therapy for the treatment of chronic hepatitis C, but the mechanisms underlying its antiviral action are not well understood. In this report, we demonstrated that IFN-alpha, -beta and -gamma inhibit replication of the hepatitis C virus (HCV) in a cell culture model at concentrations between 10 and 100 IU/ml. We demonstrated that the antiviral actions each of each these IFNs are targeted to the highly conserved 5' untranslated region of the HCV genome, and that they directly inhibit translation from a chimeric clone between full-length HCV genome and green fluorescent protein (GFP). This effect is not limited to HCV internal ribosome entry site (IRES), since these IFNs also inhibit translation of the encephalomyocardititis virus (EMCV) chimeric mRNA in which GFP is expressed by IRES-dependent mechanisms (pCITE-GFP). These IFNs had minimal effects on the expression of mRNAs from clones in which translation is not IRES dependent. We conclude that IFN-alpha, -beta and -gamma inhibit replication of sub-genomic HCV RNA in a cell culture model by directly inhibiting two internal translation initiation sites of HCV- and EMCV-IRES sequences present in the dicistronic HCV sub-genomic RNA. Results of this in vitro study suggest that selective inhibition of IRES-mediated translation of viral polyprotein is a general mechanism by which IFNs inhibits HCV replication.
authors.affiliation: Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, 1430 Tulane Avenue, New Orleans, LA 70112, USA. sdash@tulane.edu
authors.forename: Srikanta
authors.initials: S
authors.lastname: Dash
authors.forename: Ramesh
authors.initials: R
authors.lastname: Prabhu
authors.forename: Sidhartha
authors.initials: S
authors.lastname: Hazari
authors.forename: Frank
authors.initials: F
authors.lastname: Bastian
authors.forename: Robert
authors.initials: R
authors.lastname: Garry
authors.forename: Weiping
authors.initials: W
authors.lastname: Zou
authors.forename: Salima
authors.initials: S
authors.lastname: Haque
authors.forename: Virendra
authors.initials: V
authors.lastname: Joshi
authors.forename: Fredric G
authors.initials: FG
authors.lastname: Regenstein
authors.forename: Swan N
authors.initials: SN
authors.lastname: Thung
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology*; D006528:Carcinoma, Hepatocellular; D045744:Cell Line, Tumor; D005434:Flow Cytometry; D016174:Hepacivirus / Q000187:drug effects* / Q000254:growth & development; D006526:Hepatitis C / Q000188:drug therapy* / Q000821:virology; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology*; D016899:Interferon-beta / Q000494:pharmacology*; D007371:Interferon-gamma / Q000494:pharmacology*; D008113:Liver Neoplasms; D014176:Protein Biosynthesis / Q000187:drug effects; D012270:Ribosomes / Q000821:virology; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D016898:Interferon-alpha; D016899:Interferon-beta; D007371:Interferon-gamma