Fig 6.

T_reg cell populations in the lungs and PLN of M. tuberculosis-infected mice. C57BL/6, BALB/c, and DBA/2 mice were infected with a low dose of aerosolized virulent M. tuberculosis, and the presence of T_reg cells in the infected lungs (A) and PLN (B) was analyzed three (w3), or 12 weeks (w12) p.i. The bar graphs show the percentages of T_reg cells among CD4⁺ cells and the absolute numbers of T_reg cells in infected lungs (A) and PLN (B) of C57BL/6, BALB/c, and DBA/2 mice at the indicated time points after infection. The contour plots display Foxp3 expression in gated CD4⁺ cells (left) and in gated CD8⁺ cells (right) (week 12 p.i.; both T cell subsets were pregated on CD19⁻ cells [data not shown]) compared to an isotype control. The Foxp3⁺ T_reg population was analyzed in three separate experiments with five mice per group in each experiment. The plots show lung cells and PLN cells analyzed 12 weeks p.i. from one representative experiment. The results were pooled from all replicate experiments. The graphs display means and SEM. *, P < 0.05; **, P < 0.01; ***, P < 0.001 by one-way ANOVA with Bonferroni posttest.