Enterotoxigenic Escherichia coli (K88) induce proinflammatory responses in porcine intestinal epithelial cells.
Infections with F4(+) enterotoxigenic Escherichia coli (ETEC) causes severe diarrhoea in piglets, resulting in morbidity and mortality. F4 fimbriae are the key virulence factors mediating the attachment of F4(+) ETEC to the intestinal epithelium. Intestinal epithelial cells (IEC) are recently being recognized as important regulators of the intestinal immune system through the secretion of cytokines, however, data on how F4(+) ETEC affect this cytokine secretion are scarce. By using ETEC strains expressing either polymeric, monomeric or F4 fimbriae with a reduced polymeric stability, we demonstrated that polymeric fimbriae are essential for adhesion to porcine IEC and the secretion of IL-6 and IL-8 by IEC. Remarkably, this cytokine secretion was not abrogated following stimulation with an F4-negative strain. Since this strain expresses flagellin, TLR5 mediated signalling could be involved. Indeed, porcine IEC express TLR5 and purified flagellin induced IL-6 and IL-8 secretion, indicating that, as for other pathogens, flagellin is the dominant virulence factor involved in the induction of proinflammatory responses in IEC. These results indicate a potential mucosal adjuvant capacity of ETEC-derived flagellin and may improve rational vaccine design against F4(+) ETEC infections.
Devriendt
Bert
B
Laboratory of Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium. b.devriendt@Ugent.be
Stuyven
Edith
E
Verdonck
Frank
F
Goddeeris
Bruno M
BM
Cox
Eric
E
D000818:Animals; D000831:Animals, Newborn; D000942:Antigens, Bacterial / Q000235:genetics / Q000378:metabolism*; D001422:Bacterial Adhesion / Q000235:genetics; D002460:Cell Line; D003967:Diarrhea; D054307:Enterotoxigenic Escherichia coli / Q000276:immunology* / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000276:immunology* / Q000382:microbiology / Q000503:physiopathology; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D036781:Fimbriae Proteins / Q000235:genetics / Q000378:metabolism*; D005408:Flagellin / Q000378:metabolism; D007249:Inflammation; D015850:Interleukin-6 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D007413:Intestinal Mucosa / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism*; D015202:Protein Engineering; D013552:Swine; D051198:Toll-Like Receptor 5 / Q000276:immunology / Q000378:metabolism; D037521:Virulence Factors
D000942:Antigens, Bacterial; D029968:Escherichia coli Proteins; D015850:Interleukin-6; D016209:Interleukin-8; C026888:K88 antigen, E coli; D050505:Mutant Proteins; D051198:Toll-Like Receptor 5; D037521:Virulence Factors; D005408:Flagellin; D036781:Fimbriae Proteins