%0 Journal Article
%T Comparison of the Serological Reactivity of Lipopolysaccharides from Japanese and Western Strains of Helicobacter pylori to Sera from H. pylori-Positive Humans
%A Ken-ichi Amano
%A Shin-ichi Yokota
%A Mario A. Monteiro
%J ISRN Microbiology
%D 2012
%R 10.5402/2012/162816
%X We compared the serological reactivity of lipopolysaccharides (LPS) isolated from Japanese and Western strains of Helicobacter pylori against anti-Lewis antigen monoclonal antibodies and H. pylori-positive Japanese sera. The two LPS from Western strains (26695 and O:2) did not react with any sera from Japanese patients, while all LPS from Japanese strains and the Sydney strain reacted with these sera. We propose that LPS of all Japanese smooth strains share either one of two epitopes, which are termed highly antigenic and weakly antigenic epitopes, present in the O-polysaccharide portion, and these epitopes are independent the Lewis antigens. The present findings indicated that the two Western strains lacked the two epitopes, which are shared by all Japanese strains. 1. Introduction Helicobacter pylori is a gram-negative and microaerophilic bacterium that is recognized as a major cause of chronic gastritis, peptic ulcer, and gastric cancer [1, 2]. The chemistry and biology of H. pylori lipopolysaccharides (LPS) have been extensively studied. Aspinall et al. [3] and Monteiro et al. [4] determined the structures of the O-polysaccharides of H. pylori LPS and found them to be the same as the Lewis X (Lex) and Lewis Y (Ley) determinants of human cell-surface glycoconjugates. Appelmelk et al. [5] suggested that the mimicry of Lewis antigens by this bacterium raised titers of autoantibodies to Lewis antigens in infected individuals. 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¨C9]. These are unlikely to be related to the structures mimicking Lewis antigens. Most H. pylori-infected individuals have high titers of antibody to one of these antigenic epitope (the highly antigenic epitope). So we proposed that an LPS possessing this antigenic epitope would be a strong candidate for an antibody diagnosis of H. pylori infection [10]. Monteiro et al. [11] compared the structures between H. pylori LPS isolated from Asian and Western patients and found that the Asian strains showed a stronger tendency to produce type 1 blood groups. In this paper, we compared the reactivity of H. pylori LPS from Japanese and Western strains to the sera of H. pylori-positive humans. 2. Materials and Methods 2.1. Bacterial Strains and Preparation of LPS Japanese H. pylori strains (GU2, DU1, CA2, CA4, and CA5) were
%U http://www.hindawi.com/journals/isrn.microbiology/2012/162816/