A study was designed to identify receptors for K88ac fimbriae of enterotoxigenic <I>E.coli</I> (ETEC) in the small intestinal mucosa of the piglet. K88ac fimbriae were purified and labelled via amino groups using digoxigenin-3-O-methylcarbonyl-Ε-aminocaproic acid-N-hydroxy-succinimide ester, and their binding activity was demonstrated in haemagglutination assay. Digoxigenin-labelled fimbriae were then used as probes in Western blot overlay analyses of piglet intestinal brush border membranes, and a family of high molecular weight glycoproteins (>250 kDa) that specifically bound K88ac fimbriae was detected. Expression of these glycoproteins was shown to correlate with susceptibility both to K88ac-mediated adhesion of <I>E.coli in vitro</I> and K88ac-mediated enterotoxicosis <I>in vivo</I>. A weakly adhesive piglet phenotype, identified in <I>in vitro</I> brush border cell adhesion assays, was found to be associated with the presence of a 200 kDa glycoprotein in the intestinal brush border membrane. It would seem that these glycoproteins are the receptors used by <I>E.coli</I> K88ac to adhere to the piglet intestinal epithelium, and their presence may be the basis for susceptibility to K88ac-mediated ETEC infections. In anticipation of being able to develop strategies for inhibiting pathogen adherence, the nature of the K88ac fimbrial-receptors was examined. Methods for the recovery of the receptor glycoproteins were assessed, and partial purification was achieved by affinity chromatography using K88ac fimbriae immobilised on Sepharose beads.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:386937 |
| Date | January 1994 |
| Creators | Flanagan, Alison J. |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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