A novel Helicobacter pylori cell-surface polysaccharide.
Helicobacter pylori bacteria colonize the gastric mucosa of more than half of the world's human population and its infection may instigate a wide spectrum of gastric diseases in the host. At the moment, there is no vaccine against H. pylori, a microorganism recognized as a category 1 human carcinogen, and treatment is limited to antibiotic management. Pioneering antigenic studies carried out by Penner and co-workers, which employed homologous H. pylori antisera specific for cell-surface lipopolysaccharide (LPS), revealed the presence of six distinct H. pylori serotypes (O1 to O6). Subsequent studies have shown that H. pylori serotype O1 expressed LPS with lengthy O-chain polysaccharide (PS) composed of Lewis blood-group structures ('Lewis O-chains'), serotype O3 LPS produced 'Lewis O-chains' attached to a heptoglycan domain, serotype O4 LPS possessed LPS with glucosylated 'Lewis O-chains' and serotype O6 LPS expressed the heptoglycan domain capped by a short 'Lewis O-chain'. These LPSs were terminated at the reducing-end by a core oligosaccharide and lipid A of conserved structures. With the intent of formulating a multivalent H. pylori LPS-based vaccine, we are studying the structural variability of H. pylori cell-surface glycans. Here, we describe the novel LPS structure produced by H. pylori serotype O2 that differed markedly from the typical H. pylori 'Lewis O-chain' structures, in that its main component was an elongated PS composed of alternating 2-, and 3-monosubstituted alpha-D-Glcp residues [-->2)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->]n. These findings revealed the bio-molecular basis for the observed serospecificity of H. pylori serotype O2, and that this unique bacterial PS must be included in the formulation of a multivalent LPS H. pylori vaccine.
Britton
Stacey
S
Department of Chemistry, University of Guelph, Guelph, ON N1G 2W1, Canada.
Papp-Szabo
Erzsebet
E
Simala-Grant
Joanna
J
Morrison
Lisa
L
Taylor
Diane E
DE
Monteiro
Mario A
MA
D001428:Bacterial Vaccines / Q000737:chemistry / Q000276:immunology; D002240:Carbohydrate Sequence; D016480:Helicobacter pylori / Q000276:immunology*; D007983:Lewis Blood Group Antigens / Q000276:immunology; D016256:Lewis X Antigen / Q000276:immunology; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D015394:Molecular Structure
D001428:Bacterial Vaccines; D007983:Lewis Blood Group Antigens; D016256:Lewis X Antigen; D008070:Lipopolysaccharides; C504010:lipopolysaccharide, Helicobacter pylori serotype O2