Immunogenic compositions and subunit vaccines for dental caries are described which comprise peptide subunits of glucan binding protein-B and peptide subunits of glucan binding protein-B in combination with peptide subunits of glucosyltransferase. Methods of provoking an immune response to S. mutans glucan binding protein-B or glucosyltransferase. Methods of immunizing a mammal against dental caries are also described, along with antibodies which bind particular epitopes of glucan binding protein-B or glucosyltransferase.