title: Implication of antigenic conversion of Helicobacter pylori lipopolysaccharides that involve interaction with surfactant protein D.
abstract: We propose two antigenic types of Helicobacter pylori lipopolysaccharides (LPS): highly antigenic epitope-carrying LPS (HA-LPS) and weakly antigenic epitope-carrying LPS (WA-LPS) based on human serum reactivity. Strains carrying WA-LPS are highly prevalent in isolates from gastric cancer patients. WA-LPS exhibits more potent biological activities compared to HA-LPS, namely, upregulation of Toll-like receptor 4 (TLR4) expression and induction of enhanced epithelial cell proliferation. The results of competitive binding assays using monosaccharides and methylglycosides, as well as binding assays using glycosidase-treated LPS, suggested that β-linked N-acetyl-D-glucosamine and β-linked D-galactose residues largely contributed to the highly antigenic epitope and the weakly antigenic epitope, respectively. WA-LPS exhibited greater binding activity to surfactant protein D (SP-D) in a Ca(2+)-dependent manner, and this interaction was inhibited by methyl-β-D-galactoside. The biological activities of WA-LPS were markedly enhanced by the addition of SP-D. Lines of evidence suggested that removal of β-N-acetyl-D-glucosamine residue, which comprises the highly antigenic epitope, results in exposure of the weakly antigenic epitope. The weakly antigenic epitope interacted preferentially with SP-D, and SP-D enhanced the biological activity of WA-LPS.
authors.affiliation: Department of Microbiology, Sapporo Medical University School of Medicine, Chuo-ku, Sapporo, Japan. syokota@sapmed.ac.jp
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Yokota
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Amano
authors.forename: Chiaki
authors.initials: C
authors.lastname: Nishitani
authors.forename: Shigeru
authors.initials: S
authors.lastname: Ariki
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kuroki
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Fujii
mesh_terms: D000942:Antigens, Bacterial / Q000378:metabolism; D015153:Blotting, Western; D002460:Cell Line; D049109:Cell Proliferation; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000378:metabolism / Q000382:microbiology; D000939:Epitopes / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000378:metabolism; D016480:Helicobacter pylori / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000276:immunology / Q000378:metabolism*; D011485:Protein Binding; D037663:Pulmonary Surfactant-Associated Protein D / Q000235:genetics / Q000378:metabolism*; D013270:Stomach / Q000166:cytology; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism
chemical_list: D000942:Antigens, Bacterial; C508606:CXCL8 protein, human; D000939:Epitopes; D016209:Interleukin-8; D008070:Lipopolysaccharides; D037663:Pulmonary Surfactant-Associated Protein D; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D006026:Glycoside Hydrolases