Characterization of the Carbohydrate Moiety of Intestinal Mucin-Type Sialoglycoprotein Receptors for the K88ac Fimbrial Adhesin of Escherichia coli

Abstract

We have previously identified two mucin-type sialoglycoproteins from porcine intestinal epithelial cells with approximate molecular masses of 210 (intestinal mucin-type glycoprotein IMTGP-1) and 240 kDa (IMTGP-2) as receptors for the K88ab and K88ac fimbrial adhesins ofEscherichia coli. These receptors are detected in intestinal brush border membrane preparations from pigs with adhesive phenotypes but not from pigs with nonadhesive phenotypes and are postulated to be important determinants of the susceptibility of pigs to K88ab+ and K88ac+ enterotoxigenic E. coli infections. Using exoglycosidase digestion studies, we have now determined that β-linked galactose is an important component in the recognition of IMTGP-1 and IMTGP-2 by the K88ac adhesin. In addition, we observed a differential distribution of the K88ac adhesin binding activity of IMTGP-1 and IMTGP-2 along the crypt-villus axis, suggesting that receptor activity is dependent on the maturation state of the intestinal epithelial cells. Brush borders from immature intestinal epithelial cells possessed the highest concentrations of IMTGP-1 and IMTGP-2 receptor activity, with a progressive decrease in receptor activity as the cells mature. To characterize the differences in the carbohydrate moieties of IMTGP-1 and IMTGP-2, we developed a procedure for purifying the receptors, using phenol extraction followed by serial lectin affinity chromatography. Carbohydrate compositional analysis of the purified receptors indicated that the carbohydrate moieties of IMTGP-1 and IMTGP-2 consist of both N- and O-glycans containing galactose, glucose, sialic acid, mannose,N-acetylgalactosamine, N-acetylglucosamine, and fucose. The major difference between the two receptors is that IMTGP-2 contains a higher percentage of monosaccharides (mannose and glucose) commonly found in N-glycans.

Characterization and purification of porcine small intestinal mucus receptor for Escherichia coli K88ac fimbrial adhesin

“…In present study, K88ac and K88+MB speci¢c receptors in small intestinal mucus were found to be, at least in part, glycoprotein in nature, judging by the result that treatment of intestinal mucus with either proteolytic enzyme or sodium metaperiodate greatly reduced the degree of adhesion of E. coli K88ac or K88+MB. These results agree with Erickson et al [13] and Grange et al [16] who reported that E. coli K88ac adhesion receptors in porcine intestinal brush border cells are mucin-type sialoglycoproteins. Earlier, Sellwood et al [19] and Anderson et al [22] reported that glycoproteins are involved in the attachment of K88 ¢mbriae to intestinal epithelial cells.…”

“…Westerman et al [15] reported that the K88ac variant is the most common, if not the only, variant of K88 adhesin found in pathogenic E. coli isolates from the major pork-producing region of the US. Most of the studies have been concerned with the characterization of receptors of K88ab ¢mbriae [6,7,8,12,14] and K88ac ¢mbriae receptors on intestinal brush border cells [13,16,17]. Few detailed studies on the K88ac ¢mbrial receptor in intestinal mucus are available.…”

In vitroevaluation of the mucin-adhesion ability and probiotic potential ofLactobacillus mucosaeLM1

“…For example, during inhibition via exclusion, other functions such as the ability to produce antimicrobial substances is important for enhancing the hostile microenvironment mediated by coaggregation (Collado et al 2008). On the other hand, for inhibition via displacement, receptor affinity of the adhesins is also important aside from overall adhesion, such as the way beta-linked galactose is essential for recognition by the E. coli K88ac adhesin (Grange et al 1998). Cunliffe et al (1999) also showed that S. Typhimurium may use a different mode of cell attachment compared to E. coli.…”

“…+), utilized; (À), not utilized. *Glycoside components of pig intestinal type mucins according toGrange et al (1998).…”

Structural basis for Myf and Psa fimbriae‐mediated tropism of pathogenic strains of Yersinia for host tissues

“…Galactosebinding specificity has been reported for a number of pathogens that attach to intestinal epithelium. For example, enterotoxigenic E. coli attach to the intestine of pigs using F4 (K88) fimbriae, which recognize terminal b1-linked galactose in glycosphingolipids (Coddens et al, 2011) and glycoproteins (Grange et al, 1998). Although F4 fimbriae belong to the FGS CU systems, the F4 fibre acts as a polyadhesin by displaying its binding site on the structural subunit FaeG.…”