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.
Rhodin
Nikki R
NR
Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32610-0424, USA.
Cutalo
Jenny M
JM
Tomer
Kenneth B
KB
McArthur
William P
WP
Brady
L Jeannine
LJ
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