title: HBsAg mutations related to occult hepatitis B virus infection in HIV-positive patients result in a reduced secretion and conformational changes of HBsAg.
abstract: Occult hepatitis B infection (OBI) is a frequent finding in human immunodeficiency virus (HIV)-infected patients. While several related mutations in the hepatitis B virus (HBV) genome have been reported, their distinct impact on HBsAg synthesis is largely obscure.
  
  
  
  Thirty-one (18%) out of 172 HIV-infected patients, who were selected from HBsAg-negative patients, were positive for HBV-DNA assigned as being OBI-positive. We generated a series of expression constructs of variant HBsAg with "a" determinant amino acid substitutions including P127L, P127T, S136Y, and P127T + S136Y using site-directed mutagenesis. The expression of variant HBsAg was examined by transient transfection in hepatoma cells, followed by HBsAg immunoassay and immunofluorescence stained with specific anti-HBs antibodies. The potential impact of amino acid substitutions at different positions for conformational changes in the HBsAg was investigated using bioinformatics.
  
  
  
  All variants comprising either single or combined mutations resulted in significantly reduced HBsAg detection in supernatants and in cell lysates of hepatoma cells transfected with the constructs. Moreover, intracellular immunofluorescence staining of cytoblocks showed perinuclear and cytoplasmic fluorescence of HBsAg constructs with significantly diminished fluorescent intensity in comparison to the wild type. Altered protein conformations by predictive models, indicating an impaired detection by the host's immune response as well as by commercial antibody-based test assays.
  
  
  
  Mutations in the "a" determinant region of HBV as often found in OBI remarkably impair the detection of HBsAg from serum and infected cells, emphasizing the relevance of alternative methods such as HBV-DNA quantification for high-risk groups like HIV-infected individuals. J. Med. Virol. 89:246-256, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Hepatitis B Molecular Laboratory, Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Ahmadreza
authors.initials: A
authors.lastname: Sadeghi
authors.affiliation: Department of Medicine III, RWTH-University Hospital Aachen, Aachen, Germany.
authors.forename: Elham
authors.initials: E
authors.lastname: Shirvani-Dastgerdi
authors.affiliation: Department of Medicine III, RWTH-University Hospital Aachen, Aachen, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Tacke
authors.affiliation: Laboratory Diagnostics Center, RWTH-University Hospital Aachen and Medical Care Center, Dr. Stein and Colleagues, Moenchengladbach, Germany.
authors.forename: Eray
authors.initials: E
authors.lastname: Yagmur
authors.affiliation: Hepatitis B Molecular Laboratory, Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Vahdat
authors.initials: V
authors.lastname: Poortahmasebi
authors.affiliation: Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mansour
authors.initials: M
authors.lastname: Poorebrahim
authors.affiliation: Iranian Research Center for HIV/AIDS, Tehran, Iran.
authors.forename: Minoo
authors.initials: M
authors.lastname: Mohraz
authors.affiliation: Iranian Research Center for HIV/AIDS, Tehran, Iran.
authors.forename: Mahboobeh
authors.initials: M
authors.lastname: Hajabdolbaghi
authors.affiliation: Iranian Research Center for HIV/AIDS, Tehran, Iran.
authors.forename: Mehrnaz
authors.initials: M
authors.lastname: Rasoolinejad
authors.affiliation: Iranian Research Center for HIV/AIDS, Tehran, Iran.
authors.forename: Ladan
authors.initials: L
authors.lastname: Abbasian
authors.affiliation: Hepatitis B Molecular Laboratory, Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Rezvaneh
authors.initials: R
authors.lastname: Jafari
authors.affiliation: Hepatitis B Molecular Laboratory, Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Fakhari
authors.affiliation: Hepatitis B Molecular Laboratory, Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Norouzi
authors.affiliation: Hepatitis B Molecular Laboratory, Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Arefeh
authors.initials: A
authors.lastname: Ebrahimian
authors.affiliation: Hepatitis B Molecular Laboratory, Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Babak
authors.initials: B
authors.lastname: Geravand
authors.affiliation: Middle East Liver Disease (MELD) Center, Tehran, Iran.
authors.forename: Seyed Moayed
authors.initials: SM
authors.lastname: Alavian
authors.affiliation: Hepatitis B Molecular Laboratory, Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Seyed Mohammad
authors.initials: SM
authors.lastname: Jazayeri
mesh_terms: D000328:Adult; D019943:Amino Acid Substitution; D002648:Child; D019295:Computational Biology; D004279:DNA, Viral / Q000097:blood; D005260:Female; D020869:Gene Expression Profiling; D015658:HIV Infections / Q000150:complications*; D006509:Hepatitis B / Q000175:diagnosis / Q000821:virology*; D006514:Hepatitis B Surface Antigens / Q000097:blood / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011487:Protein Conformation
chemical_list: D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D050505:Mutant Proteins
keywords: HBsAg mutations; hepatitis B; human immunodeficiency virus