Characterization of the Streptococcus mutans P1 epitope recognized by immunomodulatory monoclonal antibody 6-11A.
Monoclonal antibody (MAb) 6-11A directed against Streptococcus mutans surface adhesin P1 was shown previously to influence the mucosal immunogenicity of this organism in BALB/c mice. The specificity of anti-P1 serum immunoglobulin G (IgG) and secretory IgA antibodies and the subclass distribution of anti-P1 serum IgG antibodies were altered, and the ability of elicited serum antibodies to inhibit S. mutans adherence in vitro was in certain cases increased. MAb 6-11A is known to recognize an epitope dependent on the presence of the proline-rich region of the protein, although it does not bind directly to the isolated P-region domain. In this report, we show that MAb 6-11A recognizes a complex discontinuous epitope that requires the simultaneous presence of the alanine-rich repeat domain (A-region) and the P-region. Formation of the core epitope requires the interaction of these segments of P1. Residues amino terminal to the A-region also contributed to recognition by MAb 6-11A but were not essential for binding. Characterization of the MAb 6-11A epitope will enable insight into potential mechanisms of immunomodulation and broaden our understanding of the tertiary structure of P1.
Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32610-0424, USA.
Nikki R
NR
Rhodin
Jenny M
JM
Cutalo
Kenneth B
KB
Tomer
William P
WP
McArthur
L Jeannine
LJ
Brady
D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology / Q000378:metabolism; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D018604:Epitope Mapping; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology; D006801:Humans; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D010455:Peptides / Q000276:immunology / Q000378:metabolism; D011994:Recombinant Proteins / Q000276:immunology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D013295:Streptococcus mutans / Q000276:immunology*
D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D008562:Membrane Glycoproteins; D010455:Peptides; D011994:Recombinant Proteins; C055764:S-layer proteins