Characterization of the conformational epitope of Guy's 13, a monoclonal antibody that prevents Streptococcus mutans colonization in humans.
Guy's 13 is a mouse monoclonal antibody which recognizes streptococcal antigen I/II (SA I/II), a major cell surface glycoprotein of Streptococcus mutans. In a number of clinical trials, this antibody has been shown to prevent colonization in the human oral cavity. The aim of this study was to identify the SA I/II epitope recognized by Guy's 13. The data suggest that the epitope is conformational, delimited by two noncontiguous regions of the antigen: residues 45 to 457, within the N-terminal half of SA I/II, and residues 816 to 983, within the C-terminal half. In fluid-phase immunoassays a strict requirement for the simultaneous presence of both regions was demonstrated for antibody binding. Furthermore, these two regions of SA I/II were shown to have the ability to interact with each other in the absence of Guy's 13 antibody, suggesting that the normal conformation of SA I/II might be determined by the interaction of these two regions.
van Dolleweerd
Craig J
CJ
Department of Oral Medicine and Pathology at Guy's, King's, and St. Thomas's Hospital Medical Schools, London, United Kingdom.
Chargelegue
Daniel
D
Ma
Julian K-C
JK
D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology*; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D001665:Binding Sites; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping; D000939:Epitopes / Q000737:chemistry* / Q000276:immunology; D006801:Humans; D015151:Immunoblotting; D008562:Membrane Glycoproteins; D051379:Mice; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D013295:Streptococcus mutans / Q000254:growth & development / Q000276:immunology*
D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D000939:Epitopes; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; C055764:S-layer proteins