Serum antibodies to Porphyromonas gingivalis in children.

Serum samples from 41 periodontally healthy children aged 1 to 16 years were examined by ELISA for the presence of antibodies against a glass bead-EDTA cell surface extract (GBE) and LPS of Porphyromonas gingivalis strain ATCC 33277. P. gingivalis was detected by immunofluorescence, using a species-specific monoclonal antibody, in 41% (17/41) of the children, and isolated from a single subject (2.4%). IgM, IgG, and IgA against GBE were detected in respectively 39/41 (95%), 41/41 (100%), and 27/41 (66%) of the sera. In 22/39 sera, the IgG titer was below 50% that of a reference pool of adult sera (RP). In 13/41, the IgM titer was higher than that of the RP, mostly in the deciduous dentition group. Detectable IgA titers were always below 67% that of the RP. A polarized distribution of the children appeared, separating 21 non- and low IgA responders (IgA titer below 10% that of the RP) from the remaining 20 subjects. Anti-LPS IgG, IgM, and IgA were detected in 41/41 (100%), 39/41 (95%), and 23/38 (61%) respectively of the children. In 32/41 sera, the anti-LPS IgG titer was below 50% that of the RP, while in 20/39 sera, IgM titers were higher. A clearcut dichotomy in IgA response was observed, allowing us to distinguish non-IgA responders (39%) and IgA responders to LPS (61%). Our results indicate that serum antibodies to P. gingivalis are highly prevalent in children, suggesting that an active primary immune response and a secondary immune response are well underway.(ABSTRACT TRUNCATED AT 250 WORDS)