Figure 1.

Paucibacillary TB and granuloma resolution following TB chemotherapy. (A) Experimental design for study 1. HIS BLT mice were generated and infected i.n. with 10² CFU of Mtb H37Rv for 8 weeks followed by treatment with RIF and INH by oral gavage (750 μg/day) for 8 weeks. Drug treatment was terminated and HIS mice were assigned to i.v. infection with 2,500 TCID₅₀ of HIV-1 (JR-CSF) or mock (PBS) using 3 mice per group. Relapse of TB was assessed at 8 weeks post-HIV infection. Infection with Mtb and drug efficacy was confirmed by CFU enumeration in tissues of 2 animals per designated (*) time point with a limit of detection of 30 organisms. Representative images from histological findings as visualized with H&E and Ziehl-Neelson staining and brightfield microscopy. (B) Granulomatous pathology characteristic of active TB in HIS mouse lung and (C) corresponding AFB present in the inflamed tissue. (D) Healthy lung from a non-infected mouse. (E) Mycobacterial burden in the lung, as determined by CFU enumeration following 8 weeks of infection and 8 weeks of drug treatment with RIF and INH. (F) Residual interstitial inflammation observed in lung following drug treatment, including (G) AFB negative inflammatory cells frequently observed in interstitium, and (H) Rare AFB observed in alveolar macrophage.