New vaccine antigens for the control of Streptococcus mutans

Abstract

The project's main objective is to continue the study of energy-dependent ABC transporters (stands for ATP-Binding Cassette) in the physiology and pathogenicity of Streptococcus mutans and to pursuit the search of recombinant antigens to be incorporated into vaccine formulations aimed at the control of dental caries in humans. Studies dealing the functional and immunological characterization of ABC transporters will focus on specific ligand-binding components, particularly the phosphate-binding protein (PstS) and the glutamate-binding protein (GlnA). The role played by these elements on the physiology and pathogenicity of S. mutans will be based on the study of specific knockout mutants, precisely deleted in the respective genes, while immunological and immunization studies will be mainly carried out with recombinant proteins generated in Bacillus subtilis strains. In addition to these antigens, the search for S. mutans candidate antigens will also include fragments of the P1 protein, responsible for the initial stages of adhesion of bacteria to the tooth surface and the most studied vaccine antigen described to date. The recombinant antigens of S. mutans will be administered via mucosal (oral and sublingual) in association with adjuvants in order to induce IgA responses in saliva able to control the colonization of dental surfaces. We also intend to evaluate the antigen vector function of genetically modified B. subtilis based on a technology recently developed by the group. The data to be generated during the protect should contribute to the understanding of nutrient transport systems in S.mutans and to the development of new prophylactic strategies/therapies against dental caries. (AU)