title: N-terminal myristoylation-dependent masking of neutralizing epitopes in the preS1 attachment site of hepatitis B virus.
abstract: OBJECTIVE
  The N-terminally myristoylated preS1 domain of the large hepatitis B surface protein (LHBs) mediates specific attachment of hepatitis B virus (HBV) to hepatocytes. Its B-cell epitopes leading to neutralization of infectivity are not yet characterized.
  
  
  METHODS
  We inserted C- and N-terminal preS1 peptides into the most immunogenic region of HBV core particles, therewith immunized Balb/c mice and determined binding properties and neutralization potential of resulting antibodies in vitro.
  
  
  RESULTS
  The particles with preS1 inserts were highly immunogenic and the corresponding anti-preS antibodies strongly bound to HBV particles from chronic carriers infected with different HBV genotypes A-F. However, antibodies binding to the C-terminal part of preS1 did not neutralize HBV infectivity for susceptible hepatocyte cultures. In contrast, antibodies elicited by the complete N-terminal attachment site of preS1(2-48) strongly neutralized with an IC50<3μg/ml of total immunoglobulin. Interestingly, antibodies against the very N-terminal part of preS1(1-21) could not neutralize infectivity although this sequence contains the most conserved and essential part of the attachment site. These antibodies reacted well with non-myristoylated preS1 peptides but only weakly with myristoylated preS1 peptides, natural HBsAg or HBV.
  
  
  CONCLUSIONS
  N-terminal myristic acid obviously favors a topology of LHBs that makes the most essential part of the preS1 attachment site inaccessible for neutralizing antibodies, whereas antibodies to neighbouring sequences neutralized very well. Thus, addition of the preS1(2-48) peptide in a highly immunogenic form to the current hepatitis B vaccine may improve protective immunity and reduce selection of escape mutations.
authors.affiliation: Institute of Medical Virology, Justus Liebig University, D-35392 Giessen, Germany.
authors.forename: Corinna M
authors.initials: CM
authors.lastname: Bremer
authors.forename: Irina
authors.initials: I
authors.lastname: Sominskaya
authors.forename: Dace
authors.initials: D
authors.lastname: Skrastina
authors.forename: Paul
authors.initials: P
authors.lastname: Pumpens
authors.forename: Ahmed Abd
authors.initials: AA
authors.lastname: El Wahed
authors.forename: Ulrike
authors.initials: U
authors.lastname: Beutling
authors.forename: Ronald
authors.initials: R
authors.lastname: Frank
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Fritz
authors.forename: Gerhard
authors.initials: G
authors.lastname: Hunsmann
authors.forename: Wolfram H
authors.initials: WH
authors.lastname: Gerlich
authors.forename: Dieter
authors.initials: D
authors.lastname: Glebe
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D057134:Antibodies, Neutralizing; D001665:Binding Sites; D018604:Epitope Mapping; D018985:Epitopes, B-Lymphocyte / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D005838:Genotype; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D017325:Hepatitis B Vaccines / Q000276:immunology; D006515:Hepatitis B virus / Q000235:genetics / Q000276:immunology*; D019694:Hepatitis B, Chronic / Q000276:immunology / Q000517:prevention & control / Q000821:virology; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D019814:Myristic Acid / Q000737:chemistry / Q000276:immunology; D011498:Protein Precursors / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D017386:Sequence Homology, Amino Acid
chemical_list: D057134:Antibodies, Neutralizing; D018985:Epitopes, B-Lymphocyte; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines; D011498:Protein Precursors; C050806:presurface protein 1, hepatitis B surface antigen; D019814:Myristic Acid