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

(A) Photomicrographs of lungs, livers and spleens from Rag1-/- mice infected with Pb18 after adoptive cell transfer of Treg, CD4+Foxp3- T cells and Treg + CD4+Foxp3- 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-/- 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; *p < 0.05; ** p < 0.005; ***p < 0.001; ND = not detectable).