Binding of the periodontitis associated bacterium Porphyromonas gingivalis to glycoproteins from human epithelial cells

Abstract

Introduction: In the present study we examined the ability of the periodontal pathogen Porphyromonas gingivalis to adhere to glycoconjugates on intact cells and to protein preparations of epithelial cells (KB cells). Methods: The KB cell protein preparation was separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred to nitrocellulose membranes by Western blotting. The membranes were used in overlay assays with labeled P. gingivalis. Flow cytometry was used to analyze attachment of bacteria to intact KB cells. Results: Glycoconjugate expression on the KB cells and in the protein preparation was confirmed. Binding was detected to several bands on the Western blots. Flow cytometry showed a distinct increase in fluorescence for strain FDC 381. Preincubation of the bacteria with mannose, fucose, N-acetylglucosamine and N-acetylgalactosamine inhibited the binding to KB cells by approximately 30% whereas preincubation with N-acetylneuraminic acid reduced the binding by 60%. Conclusion: These results indicate that carbohydrate structures are involved in the binding process of P. gingivalis to oral epithelial cells and that neuraminic acid plays a significant role in the adhesion process. © 2008 The Authors.