[Structure of lipopolysaccharides from gram-negative bacteria. III. Structure of O-specific polysaccharides]

Data on the composition and structure of O-antigens which represent polysaccharide chains of outer membrane lipopolysaccharides of gram-negative bacteria defining cell immunospecificity are reviewed with special reference to some structural features of O-antigens, such as masked regularity and occurrence in one microorganism of lipopolysaccharides with two structurally distinct polysaccharide chains. Antigenic relationships between the microorganisms belonging to different taxonomic groups are discussed.