title: Persistence of HCV in quiescent hepatic cells under conditions of an interferon-induced antiviral response.
abstract: OBJECTIVE
  Hepatitis C virus (HCV) is a common cause of chronic liver disease. Many patients do not clear the viral infection; little is known about the mechanisms of HCV persistence or the frequent failure of interferon (IFN) to eliminate it. Better culture systems are needed to study viral replication in quiescent liver cells.
  
  
  METHODS
  We used human hepatoma (Huh7.5) cells and those that had undergone proliferation arrest and differentiation (Huh7.5(dif)) to study the persistence of HCV infection following exposure of the cells to IFN-α and to compare the antiviral effects of IFN-α and IFN-λ. We validated these results with primary human hepatocytes and Huh7 cells that expressed an IFN-inducible fluorophore.
  
  
  RESULTS
  Following infection of Huh7.5(dif) cells, HCV replicated persistently and released infectious particles. Long-term exposure of the cells to IFN-α reduced HCV replication ∼1000-fold but did not eliminate the virus; viral replication rebounded after withdrawal of IFN, as it does in patients with chronic HCV infection. HCV replicated at higher levels, but not exclusively, in cells that had a low level of response to IFN-α. Following incubation of cells with equipotent concentrations of IFN-α or IFN-λ, Huh7.5(dif) cells expressed a wider pattern of IFN-stimulated genes than undifferentiated Huh7.5 cells or primary human hepatocytes, indicating that the antiviral response depends on the differentiation status of the cells.
  
  
  CONCLUSIONS
  We developed a cell culture system using hepatoma cells to study persistent HCV infection during the type I or type III IFN-induced antiviral response. The level and range of the antiviral responses were associated with the differentiation status of the cells. We propose that HCV exploits the stochastic nature of the response of hepatocytes to IFN to sustain persistence.
authors.affiliation: Department for Infectious Diseases, Molecular Virology, Heidelberg University, Heidelberg, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Bauhofer
authors.forename: Alessia
authors.initials: A
authors.lastname: Ruggieri
authors.forename: Bianca
authors.initials: B
authors.lastname: Schmid
authors.forename: Peter
authors.initials: P
authors.lastname: Schirmacher
authors.forename: Ralf
authors.initials: R
authors.lastname: Bartenschlager
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology*; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D024882:Drug Resistance, Viral / Q000502:physiology*; D019204:GTP-Binding Proteins / Q000378:metabolism; D016174:Hepacivirus / Q000187:drug effects* / Q000502:physiology; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000821:virology*; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology*; D007372:Interferons; D007378:Interleukins / Q000494:pharmacology*; D064547:Myxovirus Resistance Proteins; D014779:Virus Replication; D000095022:Interferon Lambda
chemical_list: D000998:Antiviral Agents; D015415:Biomarkers; D019204:GTP-Binding Proteins; D016898:Interferon-alpha; D007372:Interferons; D007378:Interleukins; D064547:Myxovirus Resistance Proteins; C000624353:interferon-lambda, human; D000095022:Interferon Lambda