title: Amino acid substitutions of hepatitis C virus core protein are not associated with intracellular antiviral response to interferon-α in vitro.
abstract: BACKGROUND
  Studies on patients with hepatitis C virus (HCV) of genotype 1b have suggested that amino acids (aa) 70 and/or 91 of the HCV core protein affect the outcome of interferon (IFN)-α and ribavirin (RBV) therapy, although there are no clear supporting data in vitro.
  
  
  OBJECTIVE
  This study was designed to determine the differences among the antiviral activities of HCV core proteins with various substitutions at aa70 and/or aa91.
  
  
  METHODS
  The retroviral vectors expressing the HCV core proteins with substitutions of arginine/leucine, arginine/methionine, glutamine/leucine or glutamine/methionine at aa70/aa91 were transiently transfected or stably transducted into an immortalized hepatocyte line (PH5CH8), hepatoma cell lines and an HCV-RNA replicating cell line (sOR) to evaluate antiviral responses to IFN-α or IFN-α/RBV. Sequence analysis was performed using genome-length HCV-RNA replicating cells (OR6 and AH1) to evaluate HCV core mutations during IFN-α treatment.
  
  
  RESULTS
  The promoter activity levels of IFN-stimulated genes in the transiently transfected cells or the mRNA levels of 2'-5'-oligoadenylate synthetase in the stably transducted PH5CH8 cells were not associated with the HCV core aa70 and/or aa91 substitutions during IFN-α treatment. Antiviral responses to IFN-α or IFN-α/RBV treatment were enhanced in sOR cells stably transducted with the HCV core, although there were no differences in antiviral responses among the cells expressing different core types. Sequence analysis showed no aa mutations after IFN-α treatment.
  
  
  CONCLUSIONS
  Antiviral activities were enhanced by HCV core transduction, but they were not associated with the HCV core aa70 and/or aa91 substitutions by in vitro analysis.
authors.affiliation: Department of Tumor Virology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan. fikeda@md.okayama-u.ac.jp
authors.forename: Fusao
authors.initials: F
authors.lastname: Ikeda
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Dansako
authors.forename: Go
authors.initials: G
authors.lastname: Nishimura
authors.forename: Kyoko
authors.initials: K
authors.lastname: Mori
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Kawai
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ariumi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Miyake
authors.forename: Akinobu
authors.initials: A
authors.lastname: Takaki
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nouso
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Iwasaki
authors.forename: Masanori
authors.initials: M
authors.lastname: Ikeda
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Kato
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Yamamoto
mesh_terms: D019943:Amino Acid Substitution; D000998:Antiviral Agents / Q000494:pharmacology*; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D004359:Drug Therapy, Combination; D016174:Hepacivirus / Q000187:drug effects / Q000235:genetics*; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism / Q000821:virology; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology*; D016297:Mutagenesis, Site-Directed; D012254:Ribavirin / Q000494:pharmacology; D020539:Sequence Analysis, Protein; D014162:Transfection; D014758:Viral Core Proteins / Q000235:genetics*
chemical_list: D000998:Antiviral Agents; D016898:Interferon-alpha; D014758:Viral Core Proteins; D012254:Ribavirin