Localization of a unique hepatitis B virus epitope sheds new light on the structure of hepatitis B virus surface antigen.
In a search for monoclonal antibodies (MAbs) that can bind hepatitis B virus surface antigen (HBsAg) with amino acid substitutions in the immune dominant 'a' region (escape mutants) we investigated the epitope recognition site of the human MAb 4-7B. Pepscan analysis and experiments with alanine substitution as well as substitutions known from nature pointed to residues 178-186 in the small S protein with the amino acid sequence PFVQWFVGL (key amino acids in bold) as the minimal epitope. Single amino acid substitutions at positions 122(R/K)(d/y), 134(Y/F), 145(G/R), 148(T/A) and 160(K/R)(w/r), representing 'a' region variants in recombinant HBsAg COS-I cells, did not influence binding of MAb 4-7B. Synthetic peptides (residues 175-189) including the 4-7B epitope sequence were able to evoke an anti-HBs response in rabbits. According to established polypeptide models, the 4-7B epitope region is located in the lipid layer of 20 nm HBsAg particles. The present results, however, suggest that residues 178-186 are exposed on the surface of the 20 nm particle. This may change our view of the structure of HBsAg.
Paulij
W P
WP
Organon Teknika, Boxtel, The Netherlands1.
de Wit
P L M
PLM
Organon Teknika, Boxtel, The Netherlands1.
Sünnen
C M G
CMG
Organon Teknika, Boxtel, The Netherlands1.
van Roosmalen
M H
MH
Organon Teknika, Boxtel, The Netherlands1.
Petersen-van Ettekoven
A
A
Organon Teknika, Boxtel, The Netherlands1.
Cooreman
M P
MP
Departments of Gastroenterology and Hepatology, Academic Medical Center, University of Amsterdam, The Netherlands2.
Heijtink
R A
RA
Erasmus Medical Centre Rotterdam, PO Box 1738, 3000 DR Rotterdam, The Netherlands3.
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D018604:Epitope Mapping; D018985:Epitopes, B-Lymphocyte / Q000235:genetics / Q000276:immunology*; D014644:Genetic Variation; D006514:Hepatitis B Surface Antigens / Q000235:genetics / Q000276:immunology*; D006515:Hepatitis B virus / Q000235:genetics / Q000276:immunology*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics / Q000276:immunology; D011817:Rabbits
D018985:Epitopes, B-Lymphocyte; D006514:Hepatitis B Surface Antigens; D010455:Peptides