Screening for complex carbohydrates inhibiting hemagglutinations by CFA/I- and CFA/II-expressing enterotoxigenicEscherichia colistrains

Abstract

Numerous structural families of naturally occurring glycopeptides and oligosaccharides have been evaluated as potential inhibitors of hemagglutinations mediated by CFA/I‐ and CFA/II‐positive enterotoxigenic Escherichia coli strains. Among the preparations tested were glycopeptides with short O‐linked (mucin‐type) chains, various mixtures containing N‐linked glycans (either oligomannoside‐, hybrid‐ or complex‐type), three fractions of human milk oligosaccharides, and glycopeptides derived from either pooled new‐born meconiums or pooled human red blood cell membranes. In almost all cases, the same inhibitory preparations were active toward all E. coli strains. This emphasizes the close analogy between the carbohydrate specificities of the colonization factors concerned. Such inhibitors always contained lactosamine units in their oligosaccharide backbones, but this structural requirement alone was not sufficient for activity. The glycopeptide mixture derived from human erythrocyte membranes (known to contain blood group‐related carbohydrate antigens carried by a lactosaminoglycan backbone) behaved as a potent hemagglutination inhibitor, especially towards CFA/II‐expressing strains. This last result clearly indicates the structural family in which complex carbohydrates should be selected to establish precisely the specificity of these CFA/II adhesins.

Phagocytosis of unopsonized Pseudomonas aeruginosa by murine macrophages is a two-step process requiring glucose.

“…These may be novel structures, since the other major appendages (pili and flagella) arise only from the bacterial poles ( 19). Similar appendages have been demonstrated on other Gram-negative bacteria when they adhere to eukaryotic surfaces (20,21 ). In fact, contact with specific types of surfaces induces Salmonella spp.…”

Inhibition of Adhesion of S‐Fimbriated Escherichia coli to Epithelial Cells by Meconium and Feces of Breast‐Fed and Formula‐Fed Newborns

“…Neeser et al (36,37) have been able to demonstrate a significant inhibitory effect of meconium glycopeptides on colonization factor antigen (CFA) I and Il-mediated hemagglutination by E . coli and CFA II-mediated adhesion to the enterocyte-like differentiated HT 29.…”

“…coli and CFA II-mediated adhesion to the enterocyte-like differentiated HT 29. Although adhesins of CFA I and II complexes also recognize neuraminic acidcontaining structures (38), meconium preparations used in the experiments of Neeser et al (36,37) were able to inhibit hemagglutination or adhesion to HT 29 cells even after desialination. This finding is in contrast to our results obtained with S-fimbriated E. coli: desialination of glycoproteins from all sources markedly reduced the adhesion-inhibiting capacity by 85-90%.…”