Figure 2.

Functional capabilities of myeloid derived suppressor cells (MDSC) was tested. (A) Illustrates the flow cytometry gating strategy. (B) Outlines suppression of PPD-driven T-cell proliferation by MDSCs at different ratios. Effector T-cells were co-cultured with MDSCs at a ratio of 4:1, 2:1 and 1:1, respectively. The percentage proliferation was measured using Ki67 flow cytometry staining. (C) Mycobacterial containment assays using peripheral blood cells from active TB patients to determine the effect of MDSCs from TB patients on mycobacterial survival. Briefly, monocyte-derived macrophages (MDMs) were infected with H37Rv and then co-cultured with PPD pre-primed effector T-cells with or without MDSCs for 24 hours. The impact of MDSCs on mycobacterial containment was assessed by plating surviving intracellular bacteria, and the magnitude of mycobacterial containment is expressed as % of the reference control (MDM only) for each experimental condition. *p-value of <0.05 were considered significant (Wilcoxon matched pairs test).