STRUCTURAL STUDY ON AN EXOCELLULAR POLYSACCHARIDE PRODUCED BY LACTOBACILLUS-HELVETICUS TY1-2

Lactobacillus helveticus TY1-2 produced an exocellular polysaccharide when it was cultured in reconstituted skim milk. This polysaccharide is a high molecular weight heteropolymer of D-glucopyranosyl, D-galactopyranosyl, and 2-acetamido-2-deoxy-D-glucopyranosyl residues in the molar ratio 3.0:2.8:0.9. The primary structure of the polysaccharide was shown by glycose analysis, methylation analysis, Smith degradation, and NMR spectroscopy to be composed of branched heptasaccharide repeating units having the following structure: [GRAPHICS] assays and cell-agglutination assays, using monosaccharides and periodate-oxidized O-polysaccharide showed that the glucose residue, especially the C-3-C-6 segment and the beta-anomeric configuration, in the polysaccharide is essential for the epitopes of all anti-011 mAbs; however, the detailed epitope specificities were different from one another. Furthermore, epitopes for serotyping antisera of 011 seemed to be similar to those for the human mAbs.