Fig. 3.

MctB-mediated copper resistance is required for virulence of M. tuberculosis in guinea pigs. (A) Cu concentrations in granulomatous lesions from guinea pigs infected with Mtb H37Rv. Tissue Cu was measured by atomic absorption spectroscopy in homogenates of lung parenchyma of five uninfected guinea pigs, and pooled primary granulomas were isolated by microdissection from lungs of five infected guinea pigs. *P ≤ 0.05. (B–D) Guinea pigs were infected with Mtb WT H37Rv (dark gray bars), the ΔmctB mutant ML256 (medium gray bars), and the complemented mutant ML257 (light gray bars). (B) The bacterial burden in lung, lymph node, and spleen was determined from tissue homogenates from guinea pigs 30 d after infection. *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001; number of infected animals per data point: n = 5. (C) Lung lesions were quantified from the area of total lung parenchyma affected by granulomatous inflammation. Data represents the mean percentage of affected lung for each treatment group or the mean percent area of lesions with necrosis. *P ≤ 0.05, **P ≤ 0.01; n = 5. (D) Lymph node lesions were quantified from the area of total lymph node parenchyma affected by granulomatous inflammation. Data represents the mean percentage of affected lymph node for each treatment group or the mean percent area of lesions with necrosis. *P ≤ 0.05, **P ≤ 0.01; n = 5.