Glycolipid binding epitopes involved in adherence of the periodontitis-associated bacterium Porphyromonas gingivalis Ulrika Hallén & Jonas Ångström & Annika E. Björkner Received: 27 June 2007 / Revised: 16 January 2008 / Accepted: 16 January 2008 / Published online: 5 February 2008 # Springer Science + Business Media, LLC 2008 Abstract The ability of the periodontal pathogen Porphy- romonas gingivalis to use different glycolipid structures as receptors has previously been demonstrated. The bacterium adhered to acid and nonacid glycolipids originating from human organs and to nonacid glycolipids of porcine origin. The aim of the present study was to analyze these binding epitopes by structural characterization. Glycolipid fractions with positive bacterial binding from e.g. human and porcine origin, were purified by the high performance liquid chromatography technique and thereafter used in bacterial overlay assays with 35 S-labeled P. gingivalis. Purified frac- tions with positive binding were structurally characterized by proton nuclear magnetic resonance spectroscopy. Com- plementing thin-layer chromatograms and bacterial overlay assays with pure reference glycolipid fractions and com- petition experiments with lactose were performed to define potential receptors. The P. gingivalis binding epitopes, including cerebrosides with nonhydroxy fatty acids, lacto- sylceramide with hydroxy fatty acids, sulfatides, lacto-, neolacto- and gangliotetraosylceramides, are in several instances similar to those found for other bacteria, e.g. H. pylori, H. influenzae and N. meningitidis. In addition P. gingivalis also bound to the Galα4Gal epitope of the globo series of glycolipids. In the future these results may be valuable for development of new treatment strategies, such as anti-adhesion therapies and vaccines specifically directed against P. gingivalis infection. Keywords Adhesion . Glycolipid . NMR . Porphyromonas gingivalis . Structural characterization Abbreviations BSA bovine serum albumin hFA hydroxy fatty acid HPLC high performance liquid chromatography nFA non-hydroxy fatty acid NMR nuclear magnetic resonance spectroscopy P phytosphingosine PBS phosphate buffered saline S sphingosine Introduction The anaerobic periodontal pathogen Porphyromonas gingi- valis has the ability to adhere to and invade oral epithelial cells and human pocket epithelium in vitro [46–47]. This is a crucial virulence trait that provides the bacterium with a temporary shelter against antibodies and phagocytic cells of the host. The adhesin(s) of P. gingivalis has been in main focus in the majority of the previous studies concerning the adhesion process. It has, among other things, been shown that the bacterium uses its fimbriae, when adhering to cell Glycoconj J (2008) 25:561–572 DOI 10.1007/s10719-008-9113-0 U. Hallén Department of Oral Pathology, Institute of Odontology, The Sahlgrenska Academy at Göteborg University, Box 450, SE 405 30 Göteborg, Sweden J. Ångström Department of Surgery, Sahlgrenska University Hospital/ Campus Östra, The Sahlgrenska Academy at Göteborg University, SE 413 45 Göteborg, Sweden A. E. Björkner (*) Department of Endodontology/Oral Diagnostics, Institute of Odontology, The Sahlgrenska Academy at Göteborg University, Box 450, SE 405 30 Göteborg, Sweden e-mail: annika.bjorkner@odontologi.gu.se