Chemical and immunochemical studies of the O-antigen from enteropathogenicEscherichia coli O158 lipopolysaccharide

The O-specific polysaccharide isolated from Escherichia coli O158 smooth li popolysaccharide contains L-rhamnose, D-glucose and 2-acetamido-2-deoxy-D-g alactose in the molar ratios 1:2:2. Studies on composition, methylation ana lysis and specific degradations together with a H-1 and C-13 NMR spectral s tudy established that the O-antigen is built up from a pentasaccharide repe ating unit having the following structure: [GRAPHICS] The most effective inhibitory part of the oligosaccharide from E. coli O158 lipopolysaccharide has been serologically characterized by an ELISA-inhibi tion study using different sugars. The results showed that methyl alpha- an d beta-D-GalpNAc are the most effective inhibitors among the monosaccharide s tested, while the main antibody specificity lies on the main-chain trisac charide repeating unit. (C) 1999 Elsevier Science Ltd. All rights reserved.