Immunoglobulin A antibody activity to mutans streptococci in parotid, submandibular and whole saliva

Antigen extracts of 9 strains of Streptococcus mutans, Streptococcus sobrinus, Streptococcus salivarius and Streptococcus mitis were separated in acrylamide gels by electrophoresis. Strains of the same genotype of mutans streptococci were found to have virtually identical sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns but differed clearly from other genotypes of mutans or with the reference strains S. salivarius and S. mitis. Immunoglobulin A (IgA) antibody activity to antigens of S. mutans, S. sobrinus and S. mitis in the parotid, submandibular and whole saliva of 12 people was detected by Western blotting. IgA antibodies reacted with several of the antigens, and the reaction pattern was unique for each of the individuals. To certain antigens, all the salivas blotted bands if both clear and questionable bands were counted. Significantly more blotted bands were revealed with antigens from S. mutans than S. sobrinus. The results of the 3 different salivas of the same individual had a high degree of resemblance but in a few individuals, more blotted bands were obtained with parotid saliva to S. mutans and S. sobrinus antigens.