title: T helper and B cell escape mutations within the HBc gene in patients with asymptomatic HBV infection: a study from the South-Eastern region of Iran.
abstract: BACKGROUND
  Escape mutations potentially allow viruses to avoid detection and clearance by the host immune system and may represent a mechanism through which infections may persist in some patients. The association of the mutations in the HBcAg gene with Hepatitis B asymptomatic carriers (ASC) has not been studied adequately. The current study was aimed to investigate HBcAg18-27 CTL epitope mutations in ASC patients in the South-Eastern region of Iran.
  
  
  METHODS
  100 ASC patients were selected for this study and screened for HLA-A2 using flow cytometry. HBV-DNA was extracted from the HLA-A2 positive patients and the HBc gene was amplified using PCR. Direct double sequencing was performed to analyse mutations in the HBc gene of HBV isolates from patients with ASC.
  
  
  RESULTS
  Overall, 25 (25%) of individuals were HLA-A2 positive. Direct double sequencing indicated no mutations in the HBcAg18-27 epitope. However, four mutations within the T helper and three mutations within the B cell epitopes of ASC patients were identified.
  
  
  CONCLUSIONS
  The lack of mutations within the HBcAg18-27 epitope suggests that the antigenicity of this region is not altered in HBV isolates of our patients and therefore antigen presentation would occur normally to the patient's immune system through HLA-A2. However, in the course of this study we revealed some novel mutations within the T helper and B cell epitopes that may affect the efficiencies of immune response of ASC patients against these novel HBV epitopes.
authors.affiliation: Dept. of Microbiology, Hematology and Immunology, Faculty of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
authors.forename: Shokrollah
authors.initials: S
authors.lastname: Assar
authors.forename: Mohammad Kazemi
authors.initials: MK
authors.lastname: Arababadi
authors.forename: Maryam
authors.initials: M
authors.lastname: Mohit
authors.forename: Behzad Nasiri
authors.initials: BN
authors.lastname: Ahmadabadi
authors.forename: Paul
authors.initials: P
authors.lastname: Pumpens
authors.forename: Hossein
authors.initials: H
authors.lastname: Khorramdelazad
authors.forename: Masomeh
authors.initials: M
authors.lastname: Hajghani
authors.forename: Sepideh
authors.initials: S
authors.lastname: Assar
authors.forename: Majid
authors.initials: M
authors.lastname: Araste
authors.forename: Zohre
authors.initials: Z
authors.lastname: Nekhei
authors.forename: Hossein
authors.initials: H
authors.lastname: Sendi
authors.forename: Derek
authors.initials: D
authors.lastname: Kennedy
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D000914:Antibodies, Viral; D058345:Asymptomatic Infections; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D001483:Base Sequence; D061167:Central Tolerance / Q000235:genetics / Q000276:immunology*; D004279:DNA, Viral / Q000032:analysis; D005260:Female; D006509:Hepatitis B / Q000276:immunology*; D006512:Hepatitis B Core Antigens / Q000737:chemistry / Q000235:genetics*; D054884:Host-Pathogen Interactions; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D004279:DNA, Viral; D006512:Hepatitis B Core Antigens