title: Molecular mechanisms of HBeAg in persistent HBV infection.
abstract: OBJECTIVE
  The aim of this study is to investigate the T-lymphocyte subpopulation and expression of programmed cell death-1 (PD-1), toll-like receptor (TLR)3, TLR4, and interferon (INF)-γ to illustrate the relationship between hepatitis B e antigen (HBeAg) and persistent hepatitis B virus (HBV) infection.
  
  
  METHODS
  Blood was taken from normal subjects into anticoagulation tubes to separate peripheral blood mononuclear cells (PBMCs). The PBMCs were divided into four groups and cultured with various concentrations of HBeAg for 72 h. Changes in the T-cell subset were analyzed through cell counting by flow cytometry, and expression of TLR3, TLR4, and PD-1 was assessed by flow cytometry and Western blot. The concentration of IFN-γ was analyzed using enzyme-linked immunospot (ELISPOT) experiments.
  
  
  RESULTS
  PBMCs were stimulated with various concentrations of HBeAg for 72 h and assayed by flow cytometry to determine CD4+ and CD8+ cell counts. The relative frequencies of CD4+ and CD8+ subpopulations and the CD4+/CD8+ ratio decreased compared with the control group, and T-cell impairment was significantly associated with higher HBeAg load. TLR3, TLR4, and PD-1 protein expression was assessed using flow cytometry and Western blotting. Expression of TLR3, TLR4, and PD-1 increased with increasing concentration of HBeAg. ELISPOT experiments were used to determine the concentration of IFN-γ. IFN-γ production in treatment groups was lower than in the control group. Comparing IFN-γ production in treatment groups, IFN-γ production in PBMCs stimulated with high dose of HBeAg was lower than for those stimulated with low-dose HBeAg.
  
  
  CONCLUSIONS
  HBeAg can inhibit proliferation of lymphocytes, increase TLR3, TLR4, and PD-1 expression, and decrease IFN-γ production. This may be one of the molecular mechanisms of HBV immune tolerance.
authors.affiliation: Infectious Diseases Institute, The Xiangya Hospital, Central South University, Changsha, Hunan, 410008, People's Republic of China.|Infectious Diseases Institute, The Third Xiangya Hospital, Central South University, Changsha, Hunan, 410083, People's Republic of China.
authors.forename: Li-Min
authors.initials: LM
authors.lastname: Chen
authors.affiliation: Infectious Diseases Institute, The Xiangya Hospital, Central South University, Changsha, Hunan, 410008, People's Republic of China. jiangyongfang@csu.edu.cn.
authors.forename: Xue-Gong
authors.initials: XG
authors.lastname: Fan
authors.affiliation: Liver Diseases Research Center, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, People's Republic of China.
authors.forename: Jing
authors.initials: J
authors.lastname: Ma
authors.affiliation: Liver Diseases Research Center, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, People's Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: He
authors.affiliation: Liver Diseases Research Center, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, People's Republic of China. jiangyongfang@hotmail.com.
authors.forename: Yong-Fang
authors.initials: YF
authors.lastname: Jiang
mesh_terms: D049109:Cell Proliferation / Q000502:physiology; D002478:Cells, Cultured; D006513:Hepatitis B e Antigens / Q000097:blood / Q000276:immunology*; D006515:Hepatitis B virus / Q000276:immunology*; D019694:Hepatitis B, Chronic / Q000097:blood / Q000276:immunology* / Q000821:virology; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology; D061026:Programmed Cell Death 1 Receptor / Q000096:biosynthesis / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000821:virology; D051196:Toll-Like Receptor 3 / Q000096:biosynthesis / Q000276:immunology; D051197:Toll-Like Receptor 4 / Q000096:biosynthesis / Q000276:immunology
chemical_list: D006513:Hepatitis B e Antigens; C105992:PDCD1 protein, human; D061026:Programmed Cell Death 1 Receptor; C495344:TLR3 protein, human; C495345:TLR4 protein, human; D051196:Toll-Like Receptor 3; D051197:Toll-Like Receptor 4; D007371:Interferon-gamma
keywords: Hepatitis B e antigen; Interferon-γ; Programmed cell death-1; Toll-like receptor 3; Toll-like receptor 4