Analysis of Helicobacter pylori isolates from Chile: occurrence of selective type 1 Lewis b antigen expression in lipopolysaccharide

Abstract

Previous studies have shown that the LPS of Helicobacter pylori isolated from North American and European hosts predominantly expresses type 2 Lewis x (Lex) and Ley epitopes, whilst the LPS from Asian strains has the capacity to express type 1 Lea and Leb structures. The aim of this study was to evaluate the expression of Le antigens and the cytotoxin-associated antigen (CagA) by H. pylori isolates from Chile. A total of 38 isolates were screened. The expression of Le antigens and CagA was determined by whole-cell indirect ELISA, using commercially available monoclonal anti-Le and polyclonal anti-CagA antibodies. LPS profiles of H. pylori isolates were assessed by gel electrophoresis and Western blotting. Expression of Lex and/or Ley epitopes was confirmed in 32/38 isolates (84 %), whilst 9/38 isolates (24 %) expressed type 1 Leb blood group determinants, in addition to type 2 Lex and Ley structures. Six strains (16 %) were non-typeable. The majority of H. pylori strains examined were CagA-positive (83.3 %).