title: Immunogenicity of peptides coupled with multiple T-cell epitopes of a surface protein antigen of Streptococcus mutans.
abstract: A surface protein antigen (PAc) of Streptococcus mutans, in particular the A-region of the molecule, has been noted as a possible target of effective dental caries vaccine. We have previously shown that two peptides of 19 amino acids (residues 361-379, NAKATYEAALKQYEADLAA, and residues 301-319, ANAANEADYQAKLTAYQTE), which correspond to parts of the A-region, contain both T- and B-cell epitopes for the induction of cross-reacting antibodies to the PAc. In this study, for development of an appropriate antigen as a peptide vaccine for use in prophylactic dentistry, we analysed in detail the localization of the T- and B-cell epitopes of PAc(361-379) peptide and the T-cell epitope of PAc(301-319) peptide in B10 congenic mice. In four murine major histocompatibility complex (MHC) haplotypes (H-2f,d,a and k), PAc(361-377) peptide showed T- and B-cell epitopes forming a cluster. It was found that the antibody which was induced by the immunization with the peptide was strongly cross-reactive with recombinant (r)PAc. Meanwhile, PAc(305-318) peptide, recognised by five strains of mice of different MHC haplotypes (H-2f,d,a,k and s), also bore multiple T-cell epitopes. PAc(361-377) peptide coupled to PAc(305-318) significantly elevated cross-reacting antibody levels compared to immunization with PAc(361-377) only in four H-2 haplotypes. Moreover, a peptide with PAc(305-318) coupled to the N-terminal region of PAc(361-377) produced significant cross-reacting antibody against rPAc, even in B10.S mice which had not responded to immunization with PAc(361-379) peptide. Therefore, it was suggested that coupling among the peptides forming a cluster might be effective in increasing immunogenicity. These results may provide us with a useful strategy for the design of peptide-based vaccines for S. mutans in the future.
authors.affiliation: Department of Oral Science, National Institute of Health, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Senpuku
authors.forename: T
authors.initials: T
authors.lastname: Iizima
authors.forename: Y
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: S
authors.initials: S
authors.lastname: Nagata
authors.forename: Y
authors.initials: Y
authors.lastname: Ueno
authors.forename: M
authors.initials: M
authors.lastname: Saito
authors.forename: N
authors.initials: N
authors.lastname: Hanada
authors.forename: T
authors.initials: T
authors.lastname: Nisizawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000276:immunology*; D001426:Bacterial Proteins; D003429:Cross Reactions; D003731:Dental Caries / Q000517:prevention & control*; D018985:Epitopes, B-Lymphocyte / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D005260:Female; D008562:Membrane Glycoproteins; D051379:Mice; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D013295:Streptococcus mutans / Q000276:immunology; D014612:Vaccines
chemical_list: D000906:Antibodies; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D018985:Epitopes, B-Lymphocyte; D018984:Epitopes, T-Lymphocyte; D008562:Membrane Glycoproteins; C055764:S-layer proteins; D014612:Vaccines