Immunisation with a purified protein from Streptococcus mutans against dental caries in rhesus monkeys.

A purified protein antigen, molecular weight 185,000, was prepared from Streptococcus mutans and used in the immunisation of monkeys against dental caries. 1 mg of this antigen, mixed with adjuvant and injected subcutaneously, elicited serum IgG and to a lesser extent IgA antibodies. Compared with sham-immunised monkeys, those receiving this antigen had a 70% reduction in dental caries and a smaller growth of Strep. mutans from dental plaque. The results suggest that the defined protein material isolated from Strep. mutans may be one of the antigens eliciting a protective immune response against dental caries. This antigen seems to be a suitable candidate for consideration as a vaccine for man.