Definition of the primary structure of hepatitis B virus (HBV) pre-S hepatocyte binding domain using random peptide libraries.
The pre-S-specific monoclonal antibody MA 18/7 has been shown to inhibit the binding of HBV to HepG2 cells and liver membranes. This antibody can thus be used to identify the critical residues of the pre-S region involved in the hepatocyte-binding domain. Using overlapping 7-mer peptides representing the pre-S region of HBV, the epitope recognized by MA 18/7 was shown to contain sequences from both the pre-S1 and pre-S2 regions, thus indicating that the hepatocyte-binding domain is conformationally dependent. To further characterize the primary structure of the hepatocyte-binding domain on the pre-S protein, a phage-displayed 15-mer peptide library and a 8-mer solid phase peptide library were used to analyze the fine specificity of the monoclonal antibody MA 18/7. Several mimotopes were identified with the phage-displayed peptide library, the majority of which possess a central motif with at least three identical residues present within the native pre-S1 sequence. No significant consensus sequences were found when these mimotopes were compared to the pre-S2 sequence. Mimotopes identified using the solid-phase peptide library also contained a similar motif. All phage mimotopes and a single mimotope from the solid-phase peptide library competed with recombinant HBsAg particles containing the pre-S1 region for binding to MA 18/7. Mouse antisera raised against four mimotopes from the phage display library reacted with HBsAg particles containing pre-S sequences. The data show that the structure of the pre-S molecule around the conserved DPAF motif in the pre-S region may have a functional role in binding HBV to cellular receptors, and that the central motif identified in mimotopes of this region may offer a novel strategy target for the improvement of existing hepatitis B vaccines which, at present, are mostly devoid of pre-S specificities.
D'Mello
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Department of Pathology and Infectious Diseases, Royal Veterinary College, Royal College Street, London, NW1 OTU, United Kingdom.
Partidos
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Steward
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Howard
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D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D006514:Hepatitis B Surface Antigens / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006515:Hepatitis B virus / Q000378:metabolism*; D006801:Humans; D008099:Liver / Q000821:virology*; D051379:Mice; D008969:Molecular Sequence Data; D019151:Peptide Library; D011498:Protein Precursors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D006514:Hepatitis B Surface Antigens; D019151:Peptide Library; D011498:Protein Precursors; C050806:presurface protein 1, hepatitis B surface antigen; C050807:presurface protein 2, hepatitis B surface antigen