title: Highly efficient JFH1-based cell-culture system for hepatitis C virus genotype 5a: failure of homologous neutralizing-antibody treatment to control infection.
abstract: BACKGROUND
  Recently, a hepatitis C virus (HCV) cell-culture system was developed that employed strain JFH1 (genotype 2a), and JFH1-based intra- and intergenotypic recombinants now permit functional studies of the structural genes (Core, E1, and E2), p7, and NS2 of genotypes 1-4. The goal was to adapt the system to employ genotype 5.
  
  
  METHODS
  Huh7.5 cells infected with SA13/JFH1, containing Core-NS2 of strain SA13 (genotype 5a), were monitored for Core expression and for supernatant infectivity and HCV-RNA titers. Adaptive mutations of SA13/JFH1 were identified by sequence analysis of recovered genomes and reverse-genetic studies. Receptor blockage was performed with anti-CD81 and anti-SR-BI. For neutralization experiments, SA13/JFH1 or JFH1-based viruses of other genotypes were incubated with patient sera.
  
  
  RESULTS
  SA13/JFH1 with NS2 and NS3 mutations yielded infectivity titers >10(5) TCID50/mL. Infection with SA13/JFH1 was inhibited by CD81 blocking and SR-BI blocking, respectively, and by preincubation with genotype 5a chronic-phase patient sera. Such sera had varying cross-genotype neutralization potential. However, preincubation and treatment with homologous neutralizing antibodies could not control SA13/JFH1 infection in culture.
  
  
  CONCLUSIONS
  The SA13/JFH1 culture permits genotype 5a-specific studies of Core-NS2 function and interfering agents. The ability of HCV to spread in vivo during treatment with neutralizing antibodies was confirmed in vitro.
authors.affiliation: Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases and Clinical Research Centre, Copenhagen University Hospital, Hvidovre, Denmark.
authors.forename: Tanja B
authors.initials: TB
authors.lastname: Jensen
authors.forename: Judith M
authors.initials: JM
authors.lastname: Gottwein
authors.forename: Troels K H
authors.initials: TK
authors.lastname: Scheel
authors.forename: Anne M
authors.initials: AM
authors.lastname: Hoegh
authors.forename: Jesper
authors.initials: J
authors.lastname: Eugen-Olsen
authors.forename: Jens
authors.initials: J
authors.lastname: Bukh
mesh_terms: D015703:Antigens, CD; D002460:Cell Line; D005838:Genotype; D016174:Hepacivirus / Q000235:genetics* / Q000502:physiology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D009154:Mutation; D009500:Neutralization Tests; D051122:Scavenger Receptors, Class B / Q000037:antagonists & inhibitors / Q000378:metabolism; D060225:Tetraspanin 28; D013997:Time Factors; D014758:Viral Core Proteins / Q000378:metabolism; D017361:Viral Nonstructural Proteins / Q000378:metabolism; D014776:Virus Cultivation / Q000379:methods*
chemical_list: D015703:Antigens, CD; C554798:CD81 protein, human; D007074:Immunoglobulin G; C495124:SCARB1 protein, human; D051122:Scavenger Receptors, Class B; D060225:Tetraspanin 28; D014758:Viral Core Proteins; D017361:Viral Nonstructural Proteins