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Lewis X structures in the O antigen side‐chain promote adhesion of Helicobacter pylori to the gastric epithelium
Author(s) -
Edwards Nicola J.,
Monteiro Mario A.,
Faller Gerhard,
Walsh Evelyn J.,
Moran Anthony P.,
Roberts Ian S.,
High Nicola J.
Publication year - 2000
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2000.01823.x
Subject(s) - biology , antigen , helicobacter pylori , mutant , microbiology and biotechnology , gastric mucosa , monoclonal antibody , cell adhesion molecule , antibody , biochemistry , gene , stomach , immunology , genetics
Helicobacter pylori NCTC11637 expresses a lipopolysaccharide (LPS) that comprises an O antigen side‐chain with structural homology to the human blood group antigen Lewis X (Le x ). The role of this molecule in adhesion of H. pylori to gastric epithelial cells was investigated. Mutants expressing truncated LPS structures were generated through insertional mutagenesis of rfbM and galE; genes encode GDP mannose pyrophosphorylase and galactose epimerase respectively. Compositional and structural analysis revealed that the galE mutant expressed a rough LPS that lacked an O antigen side‐chain. In contrast, an O antigen side‐chain was still synthesized by the rfbM mutant, but it lacked fucose and no longer reacted with anti‐Le x monoclonal antibodies (Mabs). The ability of these mutants to bind to paraffin‐embedded sections from the antrum region of a human stomach was assessed. Adhesion of the wild type was characterized by tropic binding to the apical surface of mucosal epithelial cells and cells lining gastric pits. In contrast, both the rfbM and galE mutants failed to demonstrate tropic binding and adhered to the tissue surface in a haphazard manner. These results indicate that LPS and, more specifically, Le X structures in the O antigen side‐chain play an important role in targeting H. pylori to specific cell lineages within the gastric mucosa. The role of Le X in this interaction was confirmed by the tropic binding of synthetic Le x , conjugated to latex beads, to gastric tissue. The observed pattern of adhesion was indistinguishable from that of wild‐type H. pylori .