Identifying Mechanisms Used by Adherent-invasive Escherichia coli Associated with Crohn Disease to Evade the Immune System
Year: 2012
Type: dissertation
Abstract: Background: Adherent-invasive Escherichia coli (AIEC) is a pathogen isolated from the ileum of patients with CD. IFNγ is a key mediator of immunity, which regulates inflammatory responses to microbial infections. Previously, we showed enterohemorrhagic E. coli prevents STAT1 activation. \nAims: To determine; 1) whether activation of STAT1 by IFNγ was prevented following AIEC infection, and 2) define the mechanisms used.\nMethods: Human epithelial cells were infected with AIEC strains or other pathogenic and commensal E. coli strains. Following infection, cells were stimulated with IFNγ. Activation of STAT1, was monitored by immunoblotting.\nResults: AIEC strains prevented STAT1 phosphorylation in response to IFNγ. Effect required live bacteria with active protein synthesis. A bacterial product was responsible for blocking STAT1 signalling and interfered with downstream signalling cascades.\nConclusion: Suppression of epithelial cell STAT1 signal transduction by AIEC strains represents a novel mechanism by which the pathogen evades host immune responses to the infection.
Source: TSpace (University of Toronto)
Author: Juan C. Ossa
Language: English
Subfield: Microbiology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W3093765076