This project developed from the project on the structure and immunochemistry of Staphylococcal polysaccharides. The objectives are several fold (a) investigate and develop methodology for structural analysis of capsular polysaccharides of pathogenic bacteria (b) development approaches for the synthesis of polysaccharide protein conjugates containing repeating structures of polysaccharides associated with pathogenic bacteria. In collaboration with Dr. R.A. Byrd of Division of Biochemistry and Biophysics, uniformly labeled 13C labeled K15 polysaccharide was prepared. This polysaccharide was used to develop 3-dimensional NMR techniques useful for the structural analysis of polysaccharides. In order to prepare a conjugate vaccine to Neisseria meningitidis Group A and to investigate the role of oligosaccharide structure and size on immunogenicity and approached was devised to chemically synthesize the repeating oligosaccharide. The first stage of the project involves the synthesis of a suitably protected and activated saccharide monomer. The following groups have been successfully introduced into N-acetylmannosamine 1-p-methoxybenzyl, 3-O-acetyl, 4-benzyl, 6-fluorenecarboxyl. In addition, the 1-protecting group has been selectively removed. The final step is the addition of a phosphoramidite group at the 1-position. In the next period a suitable linker arm will be attached to controlled pore glass and monomers will be constructed on the support.