Fig 1.

DCP mediates inhibition of intracellular mycobacteria growth in a dose-dependent manner. PBMCs were plated at a density of 1.5 × 10⁶ cells per well in round-bottom 96-well plates and incubated overnight at 37°C. After overnight incubation, nonadherent cells were washed off, and the enriched monocytes (∼1.5 × 10⁵ cells/well or ∼10% of the initial PBMC numbers = high monocyte density) were cultured for one more day before infection with BCG at a multiplicity of infection of 3 bacteria/cell. Extracellular BCG was washed off, and infected cells were treated with DCP at the indicated doses, 50 μg/ml PZA, or 10 μg/ml RIF for 72 h. Data are percent inhibition of intracellular BCG growth calculated as described in Materials and Methods. (A) Treatment with the highest dose of DCP resulted in >70% decreases in viability of intracellular mycobacteria. (B and C) Activity of DCP compared with current anti-TB drugs, PZA and RIF. Data shown are means ± standard errors of the means of results obtained with monocytes from 4 different volunteers. P values were obtained by using Mann-Whitney U tests.