Figure 7. Reproducibility of control of M. tuberculosis replication by MDMs differentiated with GM-CSF and TNF-α in combination and activated with various cytokines in 5% O₂.

(A) Reproducible control of M. tuberculosis with appropriately differentiated MDMs that were activated with IFN-γ at a physiologic tissue O₂ tension. MDMs from 24 donors were differentiated in 5% O₂ with no cytokines or with GM-CSF plus TNF-α (0.5 ng/ml each) for 14 days, exposed or not to IFN-γ (3 ng/ml), infected with M. tuberculosis on day 16 (MOI of 0.17), and lysed 2 weeks later for determination of CFU. Results from all donors were pooled to calculate averages. (B) Comparison of IFN-γ and other cytokines during the activation period. In the same experiments illustrated in A, MDMs were also activated with the indicated cytokines (each at 50 ng/ml, except for IFN-γ as indicated at 3 or 0.5 ng/ml). CFU counts from MDMs lysed 2 weeks infection are presented as percentage of those for the same donor’s MDMs given PBS instead of exogenous cytokines during the activation period.