Expression of putative Escherichia coli heat-labile enterotoxin (LT) receptors on intestinal brush borders from pigs of different ages.
Many strains of enterotoxigenic Escherichia coli (ETEC) that cause diarrhoea in young piglets secrete a heat-labile enterotoxin (LTp) that binds to specific glycoconjugates on porcine intestinal epithelial cells. Binding of LTp to an appropriate glycoconjugate facilitates the uptake and trafficking of the toxin into the cell, where it stimulates intracellular changes that promote fluid secretion and diarrhoea. The objective of the current study was to identify the LTp-binding glycoconjugates on porcine intestinal epithelial cells, the natural target cells for LTp. We found that LTp binds, in an age-correlated manner, to an acidic glycosphingolipid (GSL) that co-migrated with GM1 on thin-layer chromatography (TLC), a small acidic GSL that appears to be a sulphatide, a neutral GSL that co-migrated with neolactotetraglycosylceramide (nLc4) on TLC, and two glycoproteins (36 and 205 kDa). Of these potential LTp receptors, the GM1-co-migrating GSL was detected most intensely in young animals, while the other four LTp-binding glycoconjugates were detected most intensely in older pigs (> or= 4 weeks). Since ETEC primarily cause disease in young piglets, the GM1-co-migrating GSL is the most likely candidate for a functional LTp receptor.
Grange
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Veterinary Science Department, South Dakota State University, N. Campus Drive, PO Box 2175, SD 57007-1396, USA.
Parrish
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Erickson
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D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001427:Bacterial Toxins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D004768:Enterotoxins / Q000378:metabolism*; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D006001:Glycoconjugates / Q000378:metabolism; D007410:Intestinal Diseases / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D008871:Microvilli / Q000382:microbiology; D010504:Periodic Acid / Q000494:pharmacology; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology* / Q000473:pathology
D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D006001:Glycoconjugates; D010504:Periodic Acid; C009288:metaperiodate; C027538:heat-labile enterotoxin, E coli