The recruitment of macrophages, granulocytes, and activation of T cells in IL-22^−/− mice after low dose <i>Mtb</i> infection.

<p>C57BL/6 mice (black bars) and IL-22^−/− (white bars) mice were infected with approx. 100 CFU <i>Mtb</i> via the aerosol route. At different time points, single cell suspensions of lungs were prepared, counted and stained for flow cytometric analysis. (<b>A</b>) Numbers of total infiltrating cells, macrophages (CD11b⁺CD11c⁺MHCII⁺Gr-1^neg), granulocytes (CD11b⁺CD11c^negMHCII^negGr-1⁺) and T cells (CD4⁺ or CD8⁺). (<b>B</b>) Representative dot plots of naive (CD4/8⁺CD62L^neg/+CD44^neg), effector memory (CD4/8⁺CD62L^negCD44⁺), and central memory (CD4/8⁺CD62L⁺CD44⁺) T cells at two representative time points (22 and 254 days after infection). (<b>C</b>) Analysis of T cell populations described in (<b>B</b>) during the course of <i>Mtb</i> infection. Data in (<b>A</b>) and (<b>C</b>) represent mean ± SD of 4–5 mice per group. Statistical analysis was performed using a two-way ANOVA defining differences between C57BL/6 and IL-22^−/− mice as significant (*, p<0.05; **, p<0.01; ***, p<0.001).