The Cohesive Properties of Variants of Neisseria gonorrhoeae Strain P9: Specific Pilus-mediated and Non-specific Interactions

Abstract

The cohesive properties of virulent pilated N. gonorrhoeae strain P9 (P++) were compared with those of a non-pilated isogenic variant (P-) possessing the same outer membrane components. The binding of P++ gonococci to [human] buccal epithelial cells was dependent on pH, with an optimum at pH 6.5-7.0. This adhesion was inhibited by treatment of the buccal epithelial cells with a neuraminidase/exoglycosidase mixture. The binding of P++ gonococci to [human] erythrocytes was unaffected by pH. Pili may bind to a carbohydrate receptor present on buccal epithelial cells but lacking on erythrocytes. The adhesion of P- gonococci to erythrocytes and to buccal epithelial cells was unaffected by pH but enhanced by treatment of the cells with neuraminidase or periodate. Neuraminic acid residues on host cell surface carbohydrates presumably inhibit adhesion. P- gonococci bind to amphipathic gels, suggesting hydrophobic interactions as a possible non-specific mechanism attaching P- gonococci to host cell surfaces.