Confocal microscopy analysis of the co-localization of M.tb and lysosomes. THP-1-derived macrophages were infected with FITC-labelled M.tb (green) at an MOI of 5. After 6 days of culture at 37 °C, the cells were treated with LysoTracker (red) for 20 min. The results are expressed as the percentage of co-localization of M.tb and lysosome. (1) M.tb, M.tb-infected macrophages were maintained in RPMI1640 culture medium for 6 days; (2) M.tb+SD(CTL), M.tb-infected macrophages were maintained in RPMI1640 culture medium containing DMSO (the solution medium of SD) for 6 days. DMSO was added to the culture medium at the same volume of SD; (3) M.tb+SD, M.tb-infected macrophages were maintained in RPMI1640 culture medium containing 6 μM SD for 6 days; (4) M.tb+SD+DOR(CTL), M.tb-infected macrophages were maintained in RPMI1640 culture medium containing 6 μM SD and the solution medium of dorsomorphin (DOR), DMSO, for 6 days. DMSO was added to the culture medium based on the volume of DOR; (5) M.tb+SD+DOR, M.tb-infected macrophages were maintained in RPMI1640 culture medium containing 6 μM SD and 1 μM DOR for 6 days. Data are shown as the mean ± S.D. of 4 independent experiments carried out in triplicate, with a minimum of 50 phagosomes counted per experiment for each sample. *P < 0.05 versus M.tb group; ★P < 0.05 versus M.tb+SD group. Colour figure online only