Immunologic observations in macaques with Shigella-associated periodontal disease.

Abstract

The purpose of this study was to determine if macaques with Shigella‐associated periodontal disease (SAPD) were mounting humoral and cellular immunologic responses to Shigella flexneri. Responses to Bacteroides melaninogenicus ss. intermedius, a recognized periodontal pathogen, were also examined. Of the 12 monkeys studied, 4 were uninfected controls, 6 had SAPD, and 2 had been successfully treated for SAPD. At or near the time of immunologic testing, all animals were free of intestinal shigellosis. Antibody titers to the test organisms were determined by direct bacterial agglutination; cellular responses were determined by a serum‐free blast transformation assay. The highest antibody titers and blastogenic responses to both Shigella and Bacteroides antigens were observed in animals from the SAPD group. Monkeys with SAPD gave significantly higher antibody titers to both S. flexneri (p < 0.05) and B. melaninogenicus ss. intermedius (p < 0.01) than did the control monkeys. They also gave significantly higher blastogenic responses to PHA (p < 0.05) and S. flexneri (p < 0.05) than did control monkeys, but did not differ significantly in their blastogenic responses to Bacteroides. These results support the suggestion that Shigella is of etiologic importance in SAPD. They also suggest that a highly virulent microorganism which is a numerically minor component (< 0.1%) of the cultivable flora can elicit significant host responses.