In the absence of Tregs, mice show exacerbated inflammatory responses.

<p>(A) Photomicrographs of lungs, livers and spleens from Rag1<sup>-/-</sup> mice infected with Pb18 after adoptive cell transfer of Treg, CD4<sup>+</sup>Foxp3<sup>-</sup> T cells and Treg + CD4<sup>+</sup>Foxp3<sup>-</sup> T cells. Organ sections were stained with H&E and Grocott and examined under a light microscope with a magnification of 100×. Morphometric analysis of lesions in lungs, livers and spleens from Rag1<sup>-/-</sup> mice after 6 weeks of infection with Pb18. (B) Areas of lesions were quantified from photomicrographs of organ sections. Data represent the mean ± SD from three experiments (n ≥ 5; *<i>p</i> < 0.05; ** <i>p</i> < 0.005; ***<i>p</i> < 0.001; ND = not detectable).</p>