Mouse Models of Escherichia coli O157:H7 Infection and Shiga Toxin Injection

Figure 4

Model of the role of Stx2 in E. coli O157:H7 adherence and colonization. (a) E. coli O157:H7 elaborates Shiga toxin early during the colonization/adherence process. Stx2 exerts an effect on the host cell epithelium that leads to increased levels of cell surface-localized nucleolin. Nucleolin acts as an initial receptor for intimin, an interaction that allows E. coli O157:H7 to bind to the host epithelium and inject Tir and other TTSS effectors into the host cell. Intimin then engages Tir which, coupled with the cellular effects of other TTSS effectors, leads to host cell cytoskeletal rearrangement and formation of the characteristic A/E lesion. (b) Stx2, produced by the wild-type organism or provided to a 𝑠𝑡𝑥₂ mutant, facilitates colonization of the gastrointestinal tract. (c) Neutralizing anti-Stx2 antibody present prior to and during E. coli O157:H7 infection results in reduced levels of E. coli O157:H7 colonization of the gastrointestinal tract.