bacterial-epithelial contact is a key determinant of host innate immune responses to enteropathogenic and enteroaggregative escherichia colibacterial-epithelial接触致肠病的宿主先天免疫反应的一个关键决定因素和enteroaggregative大肠杆菌.pdf

Bacterial-Epithelial Contact Is a Key Determinant of Host Innate Immune Responses to Enteropathogenic and Enteroaggregative Escherichia coli 1,2 2 2 3 1 Lindsey A. Edwards *, Mona Bajaj-Elliott , Nigel J. Klein , Simon H. Murch , Alan D. Phillips 1 Centre for Paediatric Gastroenterology, Royal Free Hospital, London, United Kingdom, 2 Infectious Diseases and Microbiology, Institute of Child health, London, United Kingdom, 3 Division of Metabolic and Vascular Health, Warwick Medical School, Coventry, United Kingdom Abstract Background: Enteropathogenic (EPEC) and Enteroaggregative (EAEC) E. coli have similar, but distinct clinical symptoms and modes of pathogenesis. Nevertheless when they infect the gastrointestinal tract, it is thought that their flagellin causes IL-8 release leading to neutrophil recruitment and gastroenteritis. However, this may not be the whole story as the effect of bacterial adherence to IEC innate response(s) remains unclear. Therefore, we have characterized which bacterial motifs contribute to the innate epithelial response to EPEC and EAEC, using a range of EPEC and EAEC isogenic mutant strains. Methodology: Caco-2 and HEp-2 cell lines were exposed to prototypical EPEC strain E2348/69 or EAEC strain O42, in addition to a range of isogenic mutant strains. E69 [LPS, non-motile, non-adherent, type three secretion system (TTSS) negative, signalling negative] or O42 [non-motile, non-adherent]. IL-8 and CCL20 protein secretion was measured. Bacterial surface structures were assessed by negative staining Transmission Electron Microscopy. The Fluorescent-actin staining test was carried out to determine bacterial adherence. Results: Previous studies have re