An interesting property of O-antigen polysaccharide in lipopolysaccharide: Cross-talk between lipopolysaccharides of Helicobacter pylori and host cells through Lewis blood group antigens

Abstract

In humans, various peptic diseases and ailments are attributed to infection by the Gram-negative bacterium, Helicobacter pylori. Among the various pathogenic factors of H. pylori, the lipopolysaccharides (LPS) display two different characteristics to LPS of other Gram-negative bacteria. These include low biological activity and the presence of structures similar to human blood Lewis antigens. The former is derived from H. pylori lipid A structure that contains long fatty acids (βOHC18' βOHC16 and C16) and is deficient in the phosphate group at the non-reducing end of glucosamine disaccharide, compared to the lipid A structure of Escherichia coli. Epitopes similar to the Lewis antigen structure are present in the nonreducing end unit of the O-polysaccharide moiety, which may lead to the adhesion and colonization of this bacterium with human gastric epithelial cells. Recently, epitopes distinct from Lewis related antigens were identified in the O-polysaccharide moiety. These novel epitopes appear to be associated with peptic disease.