Expression of histo-blood group antigens by lipopolysaccharides of Helicobacter pylori strains from Asian hosts: the propensity to express type 1 blood-group antigens

Past studies have shown that the cell surface lipopolysaccharides (LPSs) of the ubiquitous human gastric pathogen Helicobacter pylori (a type 1 carcin ogen) isolated from people residing in Europe and North America express pre dominantly type 2 Lewis x (Le(x)) and Le(y) epitopes and, infrequently, typ e 1 Le(a), Le(b), and Le(d) antigens, This production of Lewis blood-group structures by H.pylori LPSs, similar to those found in the surfaces of huma n gastric cells, allows the bacterium to mimic its human niche. In this stu dy, LPSs of H.pylori strains extracted from patients living in China, japan , and Singapore were chemically and serologically analyzed. When compared w ith Western H.pylori LPSs, these Asian strains showed a stronger tendency t o produce type 1 blood groups. Of particular interest, and novel observatio ns in H.pylori, the O-chain regions of strains F-58C and R-58A carried type 1 Le(a) without the presence of type 2 Le(x), strains R-7A and H607 were s hown to have the capability of producing the type 1 blood group A antigen, and strains CA2, H507, and H428 expressed simultaneously the difucosyl isom eric antigens, type 1 Le(b) and type 2 Le(y), The apparent proclivity for t he production of type 1 histo-blood group antigens in Asian H.pylori LPSs, as compared with Western strains, may be an adaptive evolutionary effect in that differences in the gastric cell surfaces of the respective hosts migh t be significantly dissimilar to select for the formation of different LPS structures on the resident H.pylori strain.