TNF and susceptibility to pneumonia measurement: Four to five weeks after antibiotic treatment, TNFα-deficient mice rapidly lost weight, developed severe illness, and were terminated at 10 weeks with lung bacterial loads of 3 × 106 CFU/lung (Fig. 3B), severe inflammation and necrotic pneumonia, displaying distinct morphological signs of M. tuberculosis infection reactivation (Fig. 3C,D, Supplementary Fig. S5).