Local immunity to Bacteroides gingivalis in periodontal disease.

The histopathologic status of gingival tissue was assessed according to the criteria of Page and Schroeder.(5) Rhodamine-labeled bacteria were used to assess the antigenic specificity of plasma cells in the tissue. Examination of tissue sections revealed that 31.6% of plasma cells in the advanced lesions bound the labeled bacterium, compared with only 3.1% of the cells in the early lesions. These results indicate that local immunity to Bacteroides gingivalis in greater in the more advanced than in the earlier forms of periodontal disease.