FIGURE 1.

Both M. tuberculosis and M. smegmatis secA2 can complement the macrophage growth defect of a M. tuberculosis ΔsecA2 mutant. Murine bone marrow-derived macrophages were infected at a multiplicity of infection of 1.0 with the following strains: H37Rv (wild type), mc²3112 (ΔsecA2 mutant), mc²3112 complemented with wild type M. tuberculosis secA2 encoded on pMB162 (ΔsecA2/Mtb secA2), and mc²3112 complemented with wild type M. smegmatis secA2 encoded on pYA810 (ΔsecA2/Msm secA2). Colony forming units (CFU) were determined by plating macrophage lysates. The infection was performed with triplicate wells for each strain. The error bars represent ± standard deviation of the mean. The data are representative of two independent experiments. *, p < 0.05.