ANTIGENICITY OF A SYNTHETIC PEPTIDE FROM GLUCOSYLTRANSFERASES OF STREPTOCOCCUS-MUTANS IN HUMANS

Human salivary immunoglobulin A (IgA) and serum IgG antibodies to the Streptococcus mutans glucosyltransferases (Gtfs) and to a synthetic pe ptide of 19 amino acids from a conserved region in the Gtfs (residues 435 to 453) were determined in young adults by enzyme-linked immunosor bent assay. Varying levels of antibody to Gtfs were detected in saliva or serum, with significantly higher levels of antibody to GtfD than t o GtfB/C or GtfC. Anti-Gtf IgA levels in saliva did not correlate with those of IgG in serum. Caries-free (CE) volunteers exhibited signific antly higher salivary IgA antibody levels to the peptide and to GtfB/C or GtfC than did the caries-active (CA) subjects. Preincubation of CF saliva and serum with the peptide inhibited the antibodies to the Gtf s in a dose-dependent manner, whereas preincubation of the samples fro m the CA group resulted in only partial inhibition. Our results indica ted that this 19-amino-acid peptide includes one of the major B-cell e pitopes of Gtfs and that CF individuals have higher titers of antibodi es than CA subjects.