Anti-Streptococcus mutans antibodies in saliva of children with different degrees of dental caries.

The aim of this study was to evaluate the relationship between the secretory immune system and dental caries. Forty-nine 3-5-year-old children with primary dentition were classified into three groups according to their caries indices: no caries (group I), one or two surfaces with caries lesions (group II) and rampant caries (group III). Lower numbers of mutans streptococci were found in group I in relation to groups II and III. Secretory IgA and anti-S. mutans IgA, IgM and IgG antibody levels were not significantly different among the groups. Western blotting analysis showed that some S. mutans proteins, including the 39, 59, 97 and 150 kDa molecular mass bands, were recognized by almost all the saliva samples. Antibodies against the 185 kDa band, known as antigen I/II, were present in all adults' saliva and in only one child in group III. The absence of antibodies to the 185 kDa band in children's saliva suggest a specific immunologic immaturity. Further prospective studies will be necessary to establish the possible effect of reactivity to this antigen on the S. mutans colonization in this age group.