Contrasting Transcriptional Responses of a Virulent and an Attenuated Strain of Mycobacterium tuberculosis Infecting Macrophages
Figure 1
Growth of Mtb in 7H9 enriched broth and murine bone-marrow derived macrophages.
A) Mtb H37Ra and H37Rv were grown in 7H9 enriched media in aerated roller bottle cultures over 7 days. The graph shows the means ± SEM calculated from three independent experiments performed in duplicate. RNA for microarray experiments was extracted from both cultures at day 4. B) BM-MΦ were infected with Mtb H37Ra (grey bars) or H37Rv (black bars). Four hours after infection, unbound bacteria were rinsed off and intracellular bacteria were enumerated. Both strains had been internalized equally (ca. 104 bacteria per 106 macrophages). Bacterial CFU at days 4 and 7 post-infection were assessed and are plotted as Log10 change from day 0. The means ± SEM calculated from three independent experiments (each performed in triplicate) are shown. Statistical significance was determined using the student's t-test: *P = 0.007, **P = 0.0041. Mtb RNA was extracted from this macrophage infection model at day 7.