ROS production by infected MØ. Resting MØ and IFN-γ-activated MØ were infected with wild-type, ∆kstD, or ∆kstD-kstD strains for 2 hours and cultured for 1 day. Cells were then stimulated with PMA, and ROS production was assessed using the CL assay. Data are presented as the percentage of ROS production inhibition, expressed as means ± SEMs (n = 5; *p ≤ 0.04, ∆kstD vs. wild-type or ∆kstD-kstD; Mann–Whitney U test). ops – bacteria opsonized, non-ops – bacteria non-opsonized.