Corynebacterium diphtheriae surface proteins as adhesins to human erythrocytes

Corynebacterium diphtheriae strains express non-fimbrial surface proteins a ble to recognize and bind to specific host cells receptors. Protein extract s were obtained from bacterial cells by mechanical process and ammonium sul fate precipitation at 25 and 45% (w/v) saturation. SDS-PAGE analysis of the extracts detected two polypeptide bands of 67 and 72 kDa, named 67-72 p. T he 67-72 pi rabbit anti-67-72 p IgG antibodies as well as human gastric muc in, N-acetylneuraminic acid and N-acetyl D-glucosamine molecules were able to inhibit bacterial hemagglutination. Hemagglutination assays using 67-72 p-coated latex beads and Western blot analysis of biotin-labeled 67-72 p an d erythrocyte receptors demonstrated the binding of 67-72 p to human erythr ocyte membranes. Immunolabeled colloidal gold-A protein transmission electr on microscopy using anti-67-72 p revealed a diffuse distribution of non-fim brial 67-72 p on the surface of C. diphtheriae strains of both sucrose-ferm enting and non-fermenting biotypes. Non-fimbrial lectin-like surface 67-72 p may play a role as adhesins in bacterial attachment thereby facilitating the early steps in pathogenesis of both toxigenic and non-toxigenic C. diph theriae. (C) 2001 Published by Elsevier Science B.V. on behalf of the Feder ation of European Microbiological Societies.