title: Antigenic and physicochemical characterization of the 2nd International Standard for hepatitis B virus surface antigen (HBsAg).
abstract: BACKGROUND
  Standard preparations for HBsAg are required for quality control of test kits and clinical studies on HBsAg quantitation. WHO provides purified heat inactivated HBsAg diluted in negative defribinated plasma as 2nd International Standard (IS) for quality control of tests.
  
  
  OBJECTIVE
  Study of possible alterations of antigenicity, protein composition, size and density of the heat inactivated source material (SM) for the 2nd IS.
  
  
  METHODS
  Native HBsAg and SM were examined by quantitative immune electrophoresis (QIE), SDS-PAGE, ultracentrifugation and gel chromatography. HBV DNA was sequenced and the HBsAg geno/subtype derived.
  
  
  RESULTS
  The SM contained 97,600 International Units HBsAg/ml in QIE which agreed very well with the previous evaluations by WHO using 10 different assays. In SDS-PAGE, SM showed on a strong background the small HBs proteins but no preS proteins. SM had a more heterogeneous density than native HBsAg and contained particle aggregates. The HBsAg geno/subtype of SM was A2/adw2.
  
  
  CONCLUSIONS
  The IS has very good HBs antigenicity, but it lacks the preS domains, has modified HBs proteins and is partially aggregated. While it has been proven very useful for quality control of tests, certain inconsistencies due to the altered structure of its HBsAg cannot be excluded.
authors.affiliation: Institute for Medical Virology, Justus Liebig University, Frankfurter Str. 107, 35392 Giessen, Germany.
authors.forename: Christian G
authors.initials: CG
authors.lastname: Schüttler
authors.forename: Ulrike C
authors.initials: UC
authors.lastname: Wend
authors.forename: Fabian M
authors.initials: FM
authors.lastname: Faupel
authors.forename: P Nico
authors.initials: PN
authors.lastname: Lelie
authors.forename: Wolfram H
authors.initials: WH
authors.lastname: Gerlich
mesh_terms: D000818:Animals; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D006509:Hepatitis B / Q000175:diagnosis*; D006514:Hepatitis B Surface Antigens / Q000737:chemistry* / Q000276:immunology*; D006801:Humans; D007118:Immunoassay / Q000592:standards*; D012015:Reference Standards; D014461:Ultracentrifugation; D014773:Virology / Q000379:methods*
chemical_list: D006514:Hepatitis B Surface Antigens