KIDNEY BEAN LECTIN-INDUCED ESCHERICHIA-COLI OVERGROWTH IN THE SMALL-INTESTINE IS BLOCKED BY GNA, A MANNOSE-SPECIFIC LECTIN

The reversible and dose-dependent hyperplastic growth of the small int estine and accelerated epithelial cell turnover caused by feeding rats with diets containing kidney bean lectin (PHA) increased the proporti on of immature cells on the villi whose membrane and/or cytoplasm cont ained mainly simple, polymannosylated glycans. These new alpha-linked mannosyl terminals, particularly of the damaged epithelium, facilitate d the preferential adherence of opportunistic Escherichia coli with ma nnose-sensitive Type 1 fimbriae, and other coliforms, to the glycocaly x. Accordingly, the growth of the gut was accompanied by a reversible and PHA dose-dependent overgrowth with E.coli. As expected from their common carbohydrate specificity, the inclusion in the diet of the mann ose-specific agglutinin from snowdrop (Galanthus nivalis) bulbs (GNA) significantly reduced the extent of E.coli overgrowth, but abolished n either the growth nor the damage caused by PHA to the small intestine. Thus, GNA and perhaps other mannose-specific lectins, especially when used in a preventive mode, can be used to specifically block the prol iferation of Type 1 E.coli in the small intestine.