Revised Structure of the Capsular Polysaccharide of Klebsiella Serotype 15

The capsular polysaccharide from Klebsiella Type 15 was found to contain D-galactose, D-glucose, and D-glucuronic acid in the ratios 4:1:1. Methylation analysis of the native and carboxyl-reduced polysaccharide provided informaton about the linkages of different sugar residues in the repeating unit. Partial acid hydrolysis of the polysaccharides gave three acidic and one neutral oligomers whose structures were established. The sequence of different sugar moieties were established from the structures of oligomers and from the Smith degradation of the native antigen. The anomeric configurations of different sugar residues were established with the help of 1H and 13C NMR spectral analysis of the native polysaccharides, the aldobliouronic acid and the glyceryl glycoside of the trisaccharide from Smith degradation together with the findings of enzymic hydrolysis. Based on all these results, the hexasaccharide repeating unit 1 was assigned to the K-15 polysaccharide. The results of the inhibition study of several oligomers related to K15 antigen on the homologous immune system support this structure.{fx505-01}