Immunodominant antigens of Streptococcus mutans in dental caries–resistant subjects

Previously, we reported that dental caries-resistant subjects, who have significantly fewer Streptococcus mutans in whole saliva than caries-susceptible patients, have significantly higher levels of naturally occurring binding and neutralizing parotid salivary immunoglobulin A and serum immunoglobulin G antibodies to native S. mutans antigens than caries-susceptible patients. Recent animal studies indicated that the immunogenicity of swallowed S. mutans may be altered by either saliva-coating or stomach acid-denaturation. These results suggest a difference not only in the quantity of antibody to S. mutans, but also in the antigenic epitopes that caries-resistant subjects synthesize antibody to as compared with caries-susceptible patients. In the present report, sodium dodecyl sulfate-polyacrylamide gel electrophoresis/immunoblotting studies indicate that caries-resistant subjects produce salivary immunoglobulin A and serum immunoglobulin G antibodies to several different (molecular weight: 94, 80,40, and 35 kilodaltons) as well as several similar (molecular weight: 67, 55, and 30 kilodaltons) S. mutans epitopes as compared to caries-susceptible patients. This provides additional confirmation for our previous binding and functional antibody studies, indicating that caries-resistant subjects synthesize antibodies of different specificities than caries-susceptible patients. This study supports the concept of immune regulation of dental caries by naturally occurring antibodies induced by swallowing S. mutans antigens in saliva.