NO production by infected MØ. (A) Resting MØ and IFN-γ-activated MØ were infected with wild-type, ∆kstD, or ∆kstD-kstD strains for 2 hours without inhibitors. (B) Resting MØ were pre-incubated with IRAK1/4 inhibitor for 1 hour prior to infection with ∆kstD. After culturing for 2 days, the concentration of nitrite, a stable metabolite of NO, was assessed in culture supernatants using the Griess reagent. The data are presented as nitrite concentration, expressed as means (μM) ± SEMs (n = 6; *p ≤ 0.03, strain vs. none [MØ in CM]; Wilcoxon’s signed-rank test). ops – bacteria opsonized, non-ops – bacteria non-opsonized; none – MØ in culture medium (control).