ANTIBODIES REACTIVE WITH LEPTOTRICHIA-BUCCALIS IN HUMAN-SERUM FROM INFANCY TO ADULTHOOD

Serum from 90 dentulous adults, 5 edentulous adults, newborns and children of various ages were screened for precipitating antibodies to soluble antigens of human plaque bacteria. The bacterial strains of human origin used included 2 strains of L. buccalis, 3 of Bacteroides melaninoguenicus, 2 of Vibrio spp., and 7 strains identified as fusobacteria. Of the adult sera, 2/3 gave bands of precipitate with antigens of L. buccalis, and of these .apprx. 1/4 also reacted with B. melaninogenicus. Few precipitation reactions were noted with the other bacterial strains tested. Gel-diffusion tests showed that at least 1 L. buccalis antigen to which man has antibodies is also produced by B. melaninogenicus. Indirect immunofluorescent antibody titrations using conjugates directed to human IgG [immunoglobulin G], IgM and IgA were carried out on representative sera. Titers of IgG and IgM antibodies to L. buccalis increased with age. Only IgG antibodies were found in cord sera and serum from infants 1 mo. old, suggesting that these were derived by placental transmission. The widespread occurrence of serum antibodies reactive with L. buccalis, their increase in titer with age, and persistence after extraction of the teeth suggests that these are natural or normal antibodies which may arise by hetero-immunization. Antibodies to commensal organisms may play a role in the host''s response to plaque antigens during the course of periodontal disease.