Figure 5. Role of OX40 ligation and IL-2/Ab in proliferation of adoptively transferred GFP(Foxp3)+ Tregs in vivo.
(A). CD4+GFP(Foxp3)+ Tregs were FACS sorted from Wt B6- and OX40KO-foxp3gfp reporter mice and transferred into normal B6, OX40Ltg, OX40Ltg/IL-2KO hosts (without the foxp3gfp reporter gene); each host received 1×106 sorted Tregs. The transferred Tregs in the host mice were determined 2 wks later. The dot plot shown is 1 of 4 individual experiments. (B). The OX40Ltg hosts were injected i.p. with 1.5 mg BrdU 2 weeks after adoptive transfer of sorted CD45.1+CD4+GFP(Foxp3)+ Tregs. Spleen cells were prepared 12 hrs later, permeabilized, and stained with anti-BrdU mAb. The BrdU+ cells in the CD4+CD45.1+Foxp3+ fraction were shown. The plot is 1 of 3 individual experiments. (C). The absolute number of transferred GFP(Foxp3)+ Tregs recovered from the B6 and OX40Ltg hosts is shown. Data presented are mean ± SD of 5 animals in each group. (D). Wt Foxp3(GFP)+ Tregs (CD45.1+) were transferred into congenic OX40KO foxp3gfp reporter mice (CD45.2+); the host mice were then treated with OX86 (0.25mg i.p. × 3 days) and/or IL-2/Ab (0.1ug i.p. × 3 days). Expansion of both host and transferred Tregs in the same hosts was examined 7 days later. Both the relative percentage and the absolute Treg cell number were shown. * p<0.05