Abstract
Opsonic activity and antibodies to whole cells of Streptococcus mutans, Actinomyces viscosus, Porphyromonas (Bacteroides) gingivalis and Veillonella parvula were assayed in gingival crevicular fluid washings (CFW) from subjects with low or high caries experience, but who were free of clinically detectable caries. Antibody and immunoglobulin concentrations were assayed by a solid-phase radioimmunoassay. CFW antibodies against S. mutans of the IgG class were significantly raised in subjects of low caries experience compared with high caries experience. Antibodies to A. viscosus, V. parvula and P. gingivalis showed no relationship with caries. Although IgG antibodies in CFW were significantly correlated with those in serum, comparison of specific activity suggested that a proportion of the IgG antibody to S. mutans and A. viscosus in CFW was locally produced. CFW contained opsonic activity against all bacteria tested. Opsonic activity against S. mutans, but not the other bacteria tested, was significantly greater in CFW from subjects of low caries experience compared with subjects of high caries experience. Opsonic activity was not directly correlated with the antibody titre, and was dependent on both antibody and complement. The results suggest that both opsonic activity and isotype-specific antibodies are detectable in human gingival crevicular fluid, and could play a role in the modulation of caries.