Effects of local immunization of hamsters with glucosyltransferase antigens from Streptococcus sanguis on dental caries caused by Streptococcus mutans

Abstract

Glucosyltransferase (GTF) from Strep. sanguis strain 34 was tested for antigenic relatedness to GTF from Strep. mutans and for the effect of immunization with this GTF on experimental dental caries caused by Strep. mutans. The sera and salivas of hamsters immunized in the vicinity of the salivary glands with Strep. sanguis strain 34 GTF contained high levels of antibody and GTF-inhibitory activity to the homologous GTF as well as low but significant levels of antibody activity to GTF from Strep. mutans strains E49 (serotype a) and strain 6715 (serotype g). Likewise, sera or salivas from hamsters immunized with either Strep. mutans GTF showed significant reaction with Strep. sanguis GTF in the enzyme-linked immunosorbent assay (ELISA). However, groups of hamsters locally immunized with GTF from Strep. sanguis strain 34, followed by infection with cariogenic Strep. mutans strain E49, showed no protective effect on molar tooth surfaces as measured by extent of infection, caries or lesions compared with sham-immunized groups. Control groups immunized with Strep. mutans strain 6715 GTF and infected with Strep. mutans strain E49 organisms had significantly reduced caries and numbers of lesions ( p < 0.02) compared with sham-immunized groups. Therefore, the ability of GTF antigens to elicit a protective immune response among strains of Strep. mutans did not extend to the use of GTF from Strep. sanguis strain 34 as antigen under the conditions of these experiments.