FIGURE 4.

PPD-specific IL-10–producing Tregs in milk of M. tuberculosis–immunized C57BL/6 dams. Twelve-day-old pups (n = 7) nursed by M. tuberculosis–immunized and then challenged dams were used as donors of whey clots from their stomachs. Cells from the whey clots were exposed ex vivo to PPD for 16–18 h, and the functionality of CD4⁺Foxp3⁺ (A) and CD8⁺Foxp3⁺ (B) Tregs was judged by their ability to produce IL-10. Lymphoid cells were first gated for CD4⁺ or CD8⁺, then for Foxp3⁺, and then for IL-10⁺. Example of CD4⁺Foxp3⁺ cells (C), and from those, the percentage producing IL-10 in the absence (D) or presence (E) of PPD stimulation. Data in the bar graphs are presented as a percentage of CD4⁺ or CD8⁺ and Foxp3⁺ cells also positive for IL-10. Data are expressed as mean ± SD. *p < 0.05, ****p < 0.0001.