LFA-1 deficiency results in impaired conversion of naïve T cells into Treg in vivo during lymphopenia-induced homeostatic proliferation. A-B, naïve (CD4+CD62LhighGFP-) Foxp3GFP-KI T cells (1×106cells/mouse) from WT, LFA-1-KO, LFA-1-KO/Rap1E63-Tg mice were adoptively transferred i.v. into Rag2-/- recipients. Spleens, peripheral lymph nodes (PLN), and mesenteric lymph nodes (MLN) were analyzed for GFP(Foxp3) expression five weeks after in vivo transfer (A). B, The percentage of GFP(Foxp3) expressing cells in the spleen, PLN, and MLN are shown as the mean ± SD of three independent mice.