Humoral antibody response against Bacteroides gingivalis-specific antigen recognized by monoclonal antibody in adult periodontal patients.

An antigen recognized by monoclonal antibody specific for Bacteroides gingivalis was purified in the presence of 0.5% (wt/vol) beta-octyl-glucoside by immunoadsorbent column chromatography. The purified antigen was homogeneous as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and silver staining, and the pattern of SDS-PAGE agreed with that of immunoblotting. The molecule exhibited an apparent molecular weight of about 62,000 by SDS-PAGE. The antigen was sensitive to trypsin, Staphylococcus aureus V8 protease, DNase I and II, and heating, but insensitive to RNase and neuraminidase. By the enzyme-linked immunosorbent assay method, the purified antigen was not cross-reactive with rat polyclonal antibodies to each of several black-pigmented Bacteroides species, Fusobacterium nucleatum, Eikenella corrodens, and Actinobacillus actinomycetemcomitans. These results indicate that the purified antigen is specific for B. gingivalis. Humoral antibody titers in adult periodontal patients against the specific antigen were measured by the enzyme-linked immunosorbent assay. Serum immunoglobulin G antibody titers against the specific antigen in adult periodontal patients correlated significantly with the severity of periodontal disease. However, such significant correlation was not observed with serum immunoglobulin M antibody titers.