|Green, Benedict - Ben|
Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/12/2005
Publication Date: 3/1/2006
Citation: Green, B.T., Brown, D.R. 2006. Differential effects of clathrin and actin inhibitors on internalization of escherichia coli and salmonella choleraesuis in porcine jejunal peyer's patches. Veterinary Microbiology. Interpretive Summary: By disseminating immunological information from the gut lumen to mucosal surfaces throughout the body, discrete Peyer's patch follicles in the small intestine constitute an inductive site for mucosal immunity. The uptake of antigens and other macromolecules involves the adherence of luminal material to the follicle-associated epithelium (FAE), and its subsequent capture and transcellular transport by endosomes (neutral, 1998). In addition to their role in mucosal immunity, Peyer's patches serve as portals for rapid intestinal invasion by a number of pathogenic microorganisms (Vazquez-Torres and Fang, 2000). Salmonella, (Jepson and Clark, 2001), Yersinia (Autenrieth and Firsching, 1996) and Shigella (Sansoentti et al., 1996) are among the bacterial species that have been shown to gain access to the intestinal submucosa through macropinocytosis into the FAE. On the other hand, Listeria monocytogenes internalizes in Peyer's patches through clathrin-mediated endocytosis (Velge et al., 1997). Jejunal Peyer's patches from swine internalize significant amounts of yeast as well as macromolecules such as ferritin and horseradish peroxidase. They also internalize Salmonella choleraesuis and Escherichia coli. The present study was designed to test the hypothesis that the internalization processes for pathogenic salmonellae and non-pathogenic E. coli in Peyer's patches are different. Therefore, we examined an compared the effects of the actin-distrupting drug cytochalasin D. and monodansylcadaverine, an inhibitor of clathrin-mediated endocytosis, on the internalization of the enteropathogenic S. choleraesuis vaccine strain SC-54 and both rodent- and swine-adapted commensal E. coli strains in jejunal Peyer's patches from juvenile pigs.
Technical Abstract: Peyer's patches constitute both an inductive immune site and an enteropathogen invasion route. Peyer's patch mucosae from porcine jejunum were mounted in Ussing chambers, and either Salmonella choleraesuis vaccine strain SC-54 or non-pathogenic rodent and porcine Escherichia coli strains contacted the Peyer's patch mucosa for 90 min. Internalized bacteria were quantified by a getamicin resistance assay. Monodansylcadaverine (300 'M, luminal addition), an inhibitor of clathrin-mediated endocytosis, significantly internalization of both E. Coli strains relative to tissues untreated with the inhibitor; internalization of SC-54 was unaffected. The actin-disrupting agent cytochalasin D (10 'M, luminal addition), inhibited internalization of pig-adapted E. Coli but not that of rodent-adapted E. Coli or SC-54. Internalization of SC-54 and non-pathogenic E. Coli in Peyer's patches appears to occur through different cellular routes.