Inhibition of the Interaction Between Fimbrial Haemagglutinins and Erythrocytes by D-Mannose and Other Carbohydrates

SUMMARY: Many monosaccharides, oligosaccharides and their derivatives were tested as inhibitors of agglutination of guinea-pig or horse erythrocytes by Salmonella typhimuriumor Shigella flexneri bacteria bearing type-1 fimbriae. D-Mannose and certain derivatives of mannose were strongly inhibitory, and D-fructose moderately inhibitory. Modification of any of the hydroxyl groups at the C-2, C-3, C-4 or C-6 positions in the D-mannopyranosyl molecule caused failure to inhibit, showing that these groups were necessary for binding to the activesites of the fimbrial haemagglutinin. The α-configuration at the C-1 position in D-mannose was important and carbohydrates containing α-linked D-mannose were much more active inhibitors than those containing β-linked D-mannose, which were poor inhibitors or non-inhibitors. Yeast mannan also inhibited the fimbrial reaction. Attention is drawn to the remarkable degree of similarity ofthe inhibition pattern of the type-1 fimbrial haemagglutinin of bacteria with that of concanavalin-A, the jack bean haemagglutinin.