Structural and immunochemical characterization of the type VIII group B Streptococcus capsular polysaccharide

The type VIII capsular polysaccharide has been isolated and purified from a newly described strain of group B Streptococcus which is a leading cause of sepsis and neonatal meningitis in Japan. The polysaccharide contains D-glucose, D-galactose, L-rhamnose, and sialic acid in the molar ratio 1:1:1:1. By means of high resolution H-1 nuclear magnetic resonance (H-1 NMR), C-13 NMR, and homo- and heterocorrelated NMR, the repeating unit structure of the type VIII polysaccharide was delineated as the following, [GRAPHICS] Enzymatic studies established this polysaccharide as the first from which sialic acid, linked to a branched beta-D-galactopyranosyl residue, is known to be removed by bacterial neuraminidase.