The aim of this project is prepare synthetically the repeating oligosaccharide unit of type III Group B Streptococcus and derivatives thereof. The compounds will be used for structural (NMR spectroscopy) and immunological studies. The research should establish in detail the conformational control of the sialic acid residue on type III group B Streptococcus polysaccharide. Furthermore, the role of sialic acid on the immunological reaction will be further clarified. An ELISA assay to test ante natal sera for the presence of anti-streptococcus B type specific polysaccharide antibodies will be developed. The research may also lead to the development a novel and rational strategy for the design of synthetic carbohydrate-based vaccines.