Immunodominant antigens of Porphyromonas gingivalis in patients with rapidly progressive periodontitis.
W studied 4 isolates of Porphyromonas gingivalis, ATCC 33277, 381, A7A1-28, and W50, to identify major cell surface antigens and select the best strain from which to obtain antigen for a test vaccine. Immunoglobulin G (IgG) titers measured by enzyme-linked immunosorbent assay using whole-cell sonicates as antigen were significantly elevated for the sera of 64 rapidly progressive periodontitis patients relative to sera of 30 normal control subjects for each of the 4 strains studied. Western blots were prepared for all 4 strains and developed using sera from 22 patients and 20 control subjects to identify and determine the frequency of antibody-binding components. The intensity of binding by patient sera was greatest for the 75-kDa and 55-kDa components. The 43-kDa component was also widely recognized. Strains ATCC 33277 and 381 appeared to be antigenically similar. Because of the higher serum antibody titers, the larger proportion of seropositive patients and higher frequency of binding to specific protein components in Western blots, our efforts were focussed on strain ATCC 33277. Whole-cell sonicates, proteinase K-digested sonicate, lipopolysaccharide, capsular polysaccharide, and whole-cell protein fractions were prepared and evaluated for antigenic activity. By dot immunoblot, most of the antibody binding activity was found in the whole-cell protein fraction, with much lesser amounts in lipopolysaccharide and none in capsular polysaccharide. The antibody-binding activity was accessible on the cell surface, since 98.9% of P. gingivalis-specific antibody, including antibody binding to the 43-kDa, 55-kDa components on Western blot, was removed by whole-cell adsorption. Furthermore, the 43-kDa and 55-kDa but not the 75-kDa component on intact cells were accessible for labeling with 125I, confirming their cell surface location and accessibility.
Chen
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Department of Periodontics, School of Dentistry, University of Washington, Seattle, USA.
Weinberg
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Darveau
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Engel
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D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000032:analysis / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis / Q000276:immunology; D001666:Binding Sites, Antibody; D001667:Binding, Competitive; D015153:Blotting, Western; D016022:Case-Control Studies; D006801:Humans; D015151:Immunoblotting; D016056:Immunodominant Epitopes / Q000032:analysis / Q000276:immunology*; D007074:Immunoglobulin G / Q000097:blood; D008070:Lipopolysaccharides / Q000276:immunology; D008297:Male; D010514:Periodontal Pocket / Q000276:immunology / Q000382:microbiology; D010518:Periodontitis / Q000276:immunology* / Q000382:microbiology*; D011135:Polysaccharides, Bacterial / Q000276:immunology; D016966:Porphyromonas gingivalis / Q000276:immunology*; D012703:Serotyping
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D016056:Immunodominant Epitopes; D007074:Immunoglobulin G; D008070:Lipopolysaccharides; D011135:Polysaccharides, Bacterial