Fig 3.

Y. pestis Tc proteins do not disrupt PMN membrane integrity. The membrane integrity of infected PMNs was evaluated by EthD-1 staining (A) and release of intracellular LDH into the medium (B). PMNs were incubated with Y. pestis strains for 1 h or 6 h at an MOI (bacteria/PMN) of 5 (solid bars) or 25 (hatched bars). All strains contained pCD1Δ1234 (T3SS⁺). The means and standard errors for at least three experiments are indicated. Data were analyzed by paired Student's t test or by one-way ANOVA with the Bonferroni posttest. *, P < 0.001.