Lewis antigen expression and stability in Helicobacter pylori isolated from serial gastric biopsies

The expression of Lewis antigens by the gastric pathogen Helicobacter pylor i in serial biopsy isolates was investigated to assess antigen distribution and stability. A total of 26 asymptomatic subjects were given various dose s of 3' sialyllactose for up to 56 days. Gastric biopsies were performed du ring the dosing period, as well as 30 days after dosing, which provided 127 H. pylori isolates that were examined by use of ELISA and immunoblot, A la rge proportion of subjects (14/26) yielded sequential N. pylori isolates, w hich appeared genetically identical but had variable Lewis antigen expressi on. The proportion of subjects with N. pylori isolates not expressing any L ewis antigens was greater than that previously reported (10/26), Thus, the expression of the Lewis antigens by N. pylori does not appear to be a requi rement for colonization, whereas the antigen expression after human infecti on is more variable than the previously reported rate observed with in vitr o cultures.