COMPARISON OF AN ADHERENCE DOMAIN AND A STRUCTURAL REGION OF STREPTOCOCCUS-MUTANS ANTIGEN I II IN PROTECTIVE IMMUNITY AGAINST DENTAL-CARIESIN RATS AFTER INTRANASAL IMMUNIZATION/

Previous studies have identified an N-terminal saliva-binding region ( SBR) on Streptococcus mutans surface antigen VII (AgI/II) and suggeste d its importance in the initial adherence of S. mutans to saliva-coate d tooth surfaces and subsequent development of dental caries, In this study, we compared the SBR with a C-terminal structural region of AgI/ II (AgII) in their abilities to induce protective immunity against car ies in rats. When SBR, AgII, or the whole AgI/II molecule was administ ered intranasally as a conjugate with the B subunit of cholera toxin ( CT), in the presence of CT adjuvant, substantial levels of salivary im munoglobulin A anti-AgI/II antibodies were induced. Evaluation of cari es activity showed that the SBR, though not as protective as the paren t molecule, was superior to AgII and thus can be further considered as a component in a multivalent caries vaccine.