ExoT of cytotoxic Pseudomonas aeruginosa prevents uptake by corneal epithelial cells

The presence of invasion-inhibitory activity that is regulated by the trans criptional activator ExsA of cytotoxic Pseudomonas aeruginosa has previousl y been proposed. The results of this study show that both ExoT and ExoS, kn own type III secreted effector proteins of P. aeruginosa that are regulated by ExsA, possess this activity. Invasion was reduced 94.4% by ExoT and 96. 0% by ExoS. Invasion-inhibitory activity is not linked to ADP-ribosylation activity, at least for ExoS, since a noncatalytic mutant also inhibits upta ke by an epithelial cell line (invasion was reduced 96.0% by ExoSE381A).