Survival of Mtb in MØ. (A) Resting MØ and IFN-γ-activated MØ were infected with wild-type, ∆kstD, or ∆kstD-kstD strains for 2 hours without inhibitors. Resting MØ were pre-incubated with IRAK1/4 inhibitor or anti-TLR2 blocking mAb for 1 hour prior to infection with wild-type (B) or ∆kstD (C) strains. On the day of infection and after 6 days in culture, MØ were lysed with Triton X-100 and cell lysates were plated onto agar plates. After 21 days of culture, CFUs/ml were counted. The data are presented as fold increase in CFUs/ml, expressed as means ± SEMs (n = 5; *p ≤ 0.05, ∆kstD vs. wild-type or ∆kstD-kstD; #p ≤ 0.02, ∆kstD vs. ∆kstD + IRAK1/4 or ∆kstD + anti-TLR2 mAb; Mann–Whitney U test). ops – bacteria opsonized, non-ops – bacteria non-opsonized.