FIG. 6.

Quantitative ELISAs for apoptosis of HeLa cells (A) and MDCK cells (B) infected with wild-type PA103 or PA103exsA::Ω, a mutant with a generalized defect in type III secretion. HeLa cells were infected for 6 h at an MOI of approximately 160. MDCK cells were infected for 6 h at an MOI of approximately 40. HeLa cells were susceptible to type III-mediated apoptosis, whereas MDCK cells were not. Error bars represent standard errors of the means for experiments performed in triplicate.