Figure 2.

Denileukin diftitox (DD) has an additive effect with the antimicrobial standard treatment regimen and decreases the frequency of T-regulatory cells and myeloid-derived suppressor cells (MDSCs) in lungs and spleens of Mycobacterium tuberculosis–infected animals. Groups of mice (5 mice per time point) infected with M. tuberculosis H37Rv were treated with rifampin (R; 10 mg/kg), isoniazid (H; 10 mg/kg), and pyrazinamide (Z; 150 mg/kg) daily for 5 days/week, with or without DD (DD; 35 μg/kg intraperitoneally) given as 1 cycle postinfection starting on day 11. The lungs (A) and spleens (B) were homogenized, diluted, and plated for colony-forming unit (CFU) counts. Single-cell suspension from lungs and spleens of infected mice at 14 days postinfection were analyzed by flow cytometry for frequency of Tregs (C) and MDSCs (D). *P < .05 and **P < .01.