Vibrio cholerae O1 adherence to villi and lymphoid follicle epithelium: in vitro model using formalin-treated human small intestine and correlation between adherence and cell-associated hemagglutinin levels

Abstract

Formalin-fixed human small intestinal mucosa possessing villi and lymphoid follicle epithelium of Peyer's patches at the mucosal surface was used to test the adherence ability of clinically isolated strains of Vibrio cholerae O1. V. cholerae O1 grown on CFA agar for approximately 3 h at 37 degrees C had various levels of cellular hemagglutinins (HAs) and manifested adherence abilities that were roughly correlated with the cellular HA levels, irrespective of cellular HA types. V. cholerae O1 adhered better to epithelium over ileal lymphoid follicles than to epithelium of jejunal or ileal villi. Cells of different morphology which constituted lymphoid follicle epithelium were almost equal targets for adherence. In contrast, V. cholerae O1 grown on CFA agar for approximately 20 h at 37 degrees C in many cases had lower levels of cellular HAs and adherence abilities. Contrary to the above observations with cellular HAs and adherence, piliation of V. cholerae O1 was rather more extensive at approximately 20 h of incubation at 37 degrees C than at approximately 3 h of incubation at 37 degrees C. L-Fucose inhibited adherence to a varied extent depending on the cellular HA types, while D-mannose enhanced adherence in some strains. Heating of V. cholerae O1 diminished adherence ability. This adherence model system provides a tool by which various V. cholerae O1 strains can be preliminarily tested for adherence ability and site in human small intestine.