Somatic Antigens of Shigella. The Structure of the Specific Polysaccharide Chain of Shigella dysenteriae Type 5 Lipopolysaccharide

Abstract

The specific polysaccharide was released from S. dysenteriae type 5 lipopolysaccharide by mild acidic hydrolysis and then purified by gel chromatography on Sephadex G-50. The polysaccharide was built up of residues of D-mannose, 2-acetamido-2-deoxy-D-glucose, 3-O-(D-1-carboxyethyl)-L rhamnose (rhamnolactylic acid) and O-acetyl groups in a ratio 2:1:1:1. On the basis of radiospectroscopy, methylation analysis, Smith degradation and chromium trioxide oxidation, the repeating oligosaccharide unit of the polysaccharide can be assigned the following structure: .**GRAPHIC**. where GlcNAc is 2-acetamido-2-deoxy-D-glucopyranose, Manp is mannopyranose, RhaLcA is rhamnolactylic acid and Ac is an acetyl group. The serological properties of S. dysenteriae somatic antigens are discussed in relation to the chemical structures of their specific polysaccharides.