title: The impact of hepatitis B virus precore/core gene carboxyl terminal mutations on viral biosynthesis and the host immune response.
abstract: BACKGROUND
  We aimed to elucidate the impact of hepatitis B virus (HBV) precore/core gene mutations on spontaneous hepatitis B e antigen (HBeAg) seroconversion, HBV biosynthesis, and the human immune responses in chronic HBV-infected patients.
  
  
  METHODS
  We analyzed the HBV precore/core gene sequences by cloning method in 33 chronic HBV-infected patients during the inflammatory phase before spontaneous HBeAg seroconversion. The impact of the most prevalent mutant on HBeAg biosynthesis was assessed by Western blotting and native agarose gel analysis in Huh7 cells, and the human immune responses were assessed by in vitro stimulation of CD3+ CD8+ T lymphocytes of chronic HBV-infected subjects.
  
  
  RESULTS
  The P135Q and G1896A were the most prevalent mutants before HBeAg seroconversion, acting as markers of HBeAg seroconversion (hazard ratios = 2.75 and 4.50; P = .01 and <.001, respectively). The P135Q mutants displayed decreased HBeAg secretion and HBV capsid molecular weight, while showing increased 22 kD HBeAg proprotein accumulation in Huh7 cells. The P135Q mutant peptide induced less interferon-γ expression in CD3+ CD8+ T lymphocytes in HBeAg-negative subjects compared to the wild-type peptide (P = .03).
  
  
  CONCLUSIONS
  The HBV P135Q mutant emergence during the inflammatory phase was associated with HBeAg seroconversion. It was associated with altered HBV capsid assembly, HBeAg biosynthesis, and reduced human immune responses following HBeAg seroconversion.
authors.affiliation: Department of Pediatrics.
authors.forename: Jia-Feng
authors.initials: JF
authors.lastname: Wu
authors.forename: Yen-Hsuan
authors.initials: YH
authors.lastname: Ni
authors.forename: Huey-Ling
authors.initials: HL
authors.lastname: Chen
authors.forename: Hong-Yuan
authors.initials: HY
authors.lastname: Hsu
authors.forename: Mei-Hwei
authors.initials: MH
authors.lastname: Chang
mesh_terms: D000328:Adult; D036022:Capsid Proteins / Q000276:immunology; D002460:Cell Line; D005260:Female; D006509:Hepatitis B / Q000276:immunology / Q000821:virology*; D006510:Hepatitis B Antibodies / Q000097:blood / Q000276:immunology*; D006512:Hepatitis B Core Antigens / Q000235:genetics* / Q000276:immunology; D006513:Hepatitis B e Antigens / Q000276:immunology; D006515:Hepatitis B virus / Q000235:genetics* / Q000276:immunology; D054884:Host-Pathogen Interactions / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology; D008297:Male; D009154:Mutation; D055815:Young Adult
chemical_list: D036022:Capsid Proteins; D006510:Hepatitis B Antibodies; D006512:Hepatitis B Core Antigens; D006513:Hepatitis B e Antigens; D007371:Interferon-gamma
keywords: hepatitis B e antigen; hepatitis B e antigen seroconversion; hepatitis B virus; immune escape mutant; precore/core gene