title: In vivo adaptation of hepatitis C virus in chimpanzees for efficient virus production and evasion of apoptosis.
abstract: Hepatitis C virus (HCV) employs various strategies to establish persistent infection that can cause chronic liver disease. Our previous study showed that both the original patient serum from which the HCV JFH-1 strain was isolated and the cell culture-generated JFH-1 virus (JFH-1cc) established infection in chimpanzees, and that infected JFH-1 strains accumulated mutations after passage through chimpanzees. The aim of this study was to compare the in vitro characteristics of JFH-1 strains emerged in each chimpanzee at early and late stages of infection, as it could provide an insight into the phenomenon of viral persistence. We generated full-genome JFH-1 constructs with the mutations detected in patient serum-infected (JFH-1/S1 and S2) and JFH-1cc-infected (JFH-1/C) chimpanzees, and assessed their effect on replication, infectious virus production, and regulation of apoptosis in cell culture. The extracellular HCV core antigen secreted from JFH-1/S1-, S2-, and C-transfected HuH-7 cells was 2.5, 8.9, and 2.1 times higher than that from JFH-1 wild-type (JFH-1/wt) transfected cells, respectively. Single cycle virus production assay with a CD81-negative cell line revealed that the strain JFH-1/S2, isolated from the patient serum-infected chimpanzee at a later time point of infection, showed lower replication and higher capacity to assemble infectious virus particles. This strain also showed productive infection in human hepatocyte-transplanted mice. Furthermore, the cells harboring this strain displayed lower susceptibility to the apoptosis induced by tumor necrosis factor α or Fas ligand compared with the cells replicating JFH-1/wt.
  
  
  CONCLUSIONS
  The ability of lower replication, higher virus production, and less susceptibility to cytokine-induced apoptosis may be important for prolonged infection in vivo. Such control of viral functions by specific mutations may be a key strategy for establishing persistent infection.
authors.affiliation: Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Mohsan
authors.initials: M
authors.lastname: Saeed
authors.forename: Masaaki
authors.initials: M
authors.lastname: Shiina
authors.forename: Tomoko
authors.initials: T
authors.lastname: Date
authors.forename: Daisuke
authors.initials: D
authors.lastname: Akazawa
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Watanabe
authors.forename: Asako
authors.initials: A
authors.lastname: Murayama
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Suzuki
authors.forename: Haruo
authors.initials: H
authors.lastname: Watanabe
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Hiraga
authors.forename: Michio
authors.initials: M
authors.lastname: Imamura
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Chayama
authors.forename: Youkyung
authors.initials: Y
authors.lastname: Choi
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Krawczynski
authors.forename: T Jake
authors.initials: TJ
authors.lastname: Liang
authors.forename: Takaji
authors.initials: T
authors.lastname: Wakita
authors.forename: Takanobu
authors.initials: T
authors.lastname: Kato
mesh_terms: D000818:Animals; D017209:Apoptosis; D002478:Cells, Cultured; D016174:Hepacivirus / Q000276:immunology / Q000502:physiology*; D006801:Humans; D057131:Immune Evasion; D051379:Mice; D002679:Pan troglodytes / Q000821:virology*