Increased numbers of Tregs in PD-1^−/−Foxp3^gfp mice following <i>M. tb</i> infection.

<p>Cells isolated from both lung tissues and spleens of H37Rv-infected WT Foxp3^gfp and PD-1^−/−Foxp3^gfp mice were stained with anti-CD4 and anti-CD25 antibodies at 30 days after infection and analyzed by flow cytometry. A. Total numbers of Tregs in infected WT (Foxp3^gfp) and PD-1^−/− (Foxp3^gfp) mice. PD-1^−/− mice have a two-fold increase in natural Tregs after 30 days of infection. GFP⁺ cells show the Treg cell population. B. Both lungs and spleen have increased numbers of Tregs at 30 days after infection. Total CD4⁺ T cells were gated and then expression of CD25 and Foxp3-(GFP) was analysed. C. Recruitment of mesenchymal stem cells (MSCs) in spleens of WT and PD-1^−/− mice. Cells were gated on CD3⁻CD19⁻SCA-1⁺ cells for analysis of MSCs. PD-1^−/− mice have a three-fold increase in MSCs compared to WT mice.