title: Stable HepG2- and Huh7-based human hepatoma cell lines for efficient regulated expression of infectious hepatitis B virus.
abstract: OBJECTIVE
  Hepatitis B virus (HBV) cannot be propagated in cultured cells but two human hepatoma cell lines, HepG2 and Huh7, support virus replication when transfected with HBV DNA. If standardization is required stably transfected cell lines provide distinct advantages. One such line, HepG2.2.15, is widely used in antiviral research but HBV production is limited and difficult to control. Our aim was to establish stable, inducibly HBV producing HepG2 and Huh7 cell lines that overcome these limitations.
  
  
  METHODS
  Based on the tetracycline (Tet)-regulated TetOFF system, a Tet-responsive promoter-controlled HBV genome was introduced into separately established, well-regulatable HepG2 and Huh7 lines expressing Tet-responsive trans-activators (tTAs). Stable clones were analyzed for regulatability and levels of HBV expression, quality of the virus produced, and responsiveness towards antivirals.
  
  
  RESULTS
  HepG2- and Huh7-based cell lines were established which, Tet-controllably, produce more HBV than HepG2.2.15 cells. The secreted virions were infectious for primary tupaia hepatocytes, and the cell lines responded as well as HepG2.215 cells to different antivirals.
  
  
  CONCLUSIONS
  The new HBV cell lines should be valuable tools for academic and pharmaceutical HBV research. The parental tTA-cells will facilitate the generation of additional lines, producing HBV variants, or other genes, in an identical host cell background.
authors.affiliation: University Hospital Freiburg, Internal Medicine II/Molecular Biology, Hugstetter Strasse 55, D-79106 Freiburg, Germany.
authors.forename: Dianxing
authors.initials: D
authors.lastname: Sun
authors.forename: Michael
authors.initials: M
authors.lastname: Nassal
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology; D006528:Carcinoma, Hepatocellular / Q000821:virology; D045744:Cell Line, Tumor / Q000821:virology*; D004279:DNA, Viral / Q000235:genetics* / Q000302:isolation & purification; D015967:Gene Expression Regulation, Viral; D005822:Genetic Vectors / Q000235:genetics*; D006515:Hepatitis B virus / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D006801:Humans; D008113:Liver Neoplasms / Q000821:virology; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D014771:Virion / Q000302:isolation & purification; D014776:Virus Cultivation / Q000379:methods*; D016662:Virus Integration; D014779:Virus Replication / Q000235:genetics
chemical_list: D000998:Antiviral Agents; D004279:DNA, Viral