FIG 5.

At least two Yop effector proteins are required to fully inhibit azurophilic granule release. Human neutrophils (4 × 10⁶) were coinfected with Y. pestis KIM1001 with or without the pCD1 plasmid encoding the T3SS (T3⁺ or T3⁻, respectively) or with strains expressing only ypkA (+A), yopE (+E), yopH (+H), yopJ (+J), yopK (+K), yopM (+M), or yopT (+T) mixed at a 1:1 ratio with strains expressing only (A) yopH (+H), (B) yopE (+E), (C) yopJ (+J), or (D) ypkA (+A); MOI of each strain = 50 for a combined MOI of 100. Azurophilic granule release was measured after 30 min of infection. Mean ± SEM from 5 biologically independent experiments. One-way ANOVA with Dunnett’s post hoc test. Gray bars are significantly different than T3⁻ (P ≤ 0.05); purple bars are significantly different than T3⁻/T3⁺ (P ≤ 0.05); hatched bars are not significantly different than T3⁻ or T3⁻/T3⁺.