IMMUNOGLOBULIN-A REACTION LO ORAL STREPTOCOCCI IN SALIVA OF SUBJECTS WITH DIFFERENT COMBINATIONS OF CARIES AND LEVELS OF MUTANS STREPTOCOCCI

The aim of this study, performed in Bangkok, was to study whether a pa rticular salivary immunoglobulin A (IgA) antibody profile against muta ns streptococci could be related to the absence or presence of caries. A group of 12-year-old individuals representing various combinations of mutans streptococci levels and caries experience was selected. Whol e saliva stimulated by paraffin-chewing was collected, and the childre n were investigated for decayed, missing and filled surfaces (DMFS) an d teeth (DMFT), following WHO criteria and methods, at baseline and af ter 2 years. The total amount of salivary IgA was determined by an imm unobead enzyme-linked immunosorbent assay, and SDS-PAGE and Western bl ot analysis was performed using sonicated antigens of Streptococcus mu tans and Streptococcus sobrinus strains and, as a control, a Streptoco ccus parasanguis strain. The results showed that Thai children with lo w caries prevalence had more distinct immunoblot bands to antigens fro m mutans streptococci than did the high-caries children. A similar pic ture was not seen for S. parasanguis. On the whole, the Thai children also showed fewer bands than usual Swedish saliva samples from compara ble age groups. The complexity of the relationship between dental cari es and IgA in saliva is highlighted.