Fig. 3

Blocking TLR4 and NOX2 inhibits the killing of M. tuberculosis by THP-1 cells. a M. tuberculosis was incubated with various concentrations of FDA to achieve labeling. Percentage of bacteria labeled is indicated. b FDA labeled M. tuberculosis (left most scatter plot) was incubated with THP-1(A) cells for various time periods (0–60 min). THP-1(A) cells were lysed and total phagocytized M. tuberculosis and M. tuberculosis in serum were isolated. FDA levels in M. tuberculosis were measured by flow cytometry with percentage of M. tuberculosis with FDA removed indicated (left). Graph of FDA removal levels (right). (*; P < 0.05 compared to t = 0, **; P < 0.01 compared to t = 0). c THP-1(A) cells treated without LPS, with LPS, or with LPS in combination with DPI or HTA125 pretreatment were infected with M. tuberculosis-FDA at 0 °C or 37 °C. THP-1(A) cells were lysed and total phagocytized M. tuberculosis and M. tuberculosis in serum were analyzed by flow cytometry for FDA levels. The number of viable M. tuberculosis retaining FDA is indicated (left). Graph of MFI from left (right). (*; P < 0.05). d THP-1(A) cells were treated with various concentrations of LPS (0–10,000 ng/mL), then infected with M. tuberculosis-FDA at 0 °C or 37 °C. THP-1(A) cells were lysed and total phagocytized M. tuberculosis and M. tuberculosis in serum were analyzed by flow cytometry for FDA levels. The number of viable M. tuberculosis retaining FDA is indicated. (SSC; side scatter, MFI; median fluorescence intensity)