Fig 5. B cell-depleted WT C57BL/6 mice also exhibit diminished granulomatous inflammation and Th1 response and enhanced IL-10 levels in the lungs during chronic M. tuberculosis infection.

Mice were treated with the anti-CD20 mAb 5D2 beginning 2 days prior to a low-dose (100 CFU) aerogenic challenge with M. tuberculosis Erdman, as described in "Materials and Methods". B cell depletion was maintained throughout the duration of the experiment. The control mouse group (WT) received non-specific rat IgG. The lung tissues were examined at 5 months post-infection. The levels of granulomatous inflammation response were analyzed histologically by light microscopy on H&E-stained lung sections (A) and enumeration of total number of lung cells (B). The level of lung CD4⁺ T cell response was assessed by in vivo BrdU labeling to examine the proliferation capacity of this T cell subset (C), as well as by enumeration of IFN-γ-producing CD4⁺ T cells (D). Ex vivo evaluation of lung cells for the level of IL-10 production (E) was conducted as described in Fig 4. Four to 5 mice per group were evaluated per group. Data depicted in B, C, D, and E are presented as means ± SEM. The data shown are representative of two experiments. The results demonstrated that the inflammation, Th1 response, and IL-10 phenotypes observed in the μMT mice are recapitulated in mice depleted for B cells.