Helicobacter pylori Lipopolysaccharide as a Possible Pathogenic Factor for Gastric Carcinogenesis

Comparison of the Serological Reactivity of Lipopolysaccharides from Japanese and Western Strains of Helicobacter pylori to Sera from H. pylori-Positive Humans

“…We previously proposed in [7–9] the presence of two distinct epitopes, termed the highly antigenic and the weakly antigenic epitopes, on the O-polysaccharide chains, based on data from the immunoblotting of LPS with sera from H. pylori -positive humans. Furthermore, we also proposed the classification of H. pylori -positive human sera into three groups on the basis of immunoblot reactivity to the polysaccharide region of LPS [7–9]. Type A sera only react with LPS containing the highly antigenic epitope, type B sera only react with LPS containing the weakly antigenic epitope, and type C sera react with both types of LPS.…”

“…However, we find no significant titers of anti-Lewis antigen antibodies in the sera of H. pylori -positive humans [6]. On the other hand, we have observed that all H. pylori smooth-type LPS possess either one of two antigenic epitopes (the highly antigenic and the weakly antigenic epitopes) in their polysaccharide regions [7–9]. These are unlikely to be related to the structures mimicking Lewis antigens.…”

Implication of Antigenic Conversion of Helicobacter pylori Lipopolysaccharides That Involve Interaction with Surfactant Protein D

“…We propose that H. pylori smooth-type LPS can be classified into two antigenic types, HA-LPS and WA-LPS (35,38). H. pylori clinical strains with smooth-type LPS isolated in Japan have one or the other epitope, but not both.…”

“…Lewis antigens are thought to be an escape mechanism from host immune defenses and can trigger an autoimmune response in the host (3,7,23). Third, we have identified two distinct antigenic epitopes on the polysaccharide moiety that are independent of Lewis antigen structures (35,38,39). We have termed these highly antigenic epitope and weakly antigenic epitope, respectively.…”

“…Clinical isolates having weakly antigenic epitope-carrying LPS (WA-LPS) are the dominant strain isolated from gastric cancer patients. Isolates with the highly antigenic epitope-carrying LPS (HA-LPS) are frequently isolated from patients with chronic gastritis (35,37,38).…”