In vivo injection of oIL-2 and oIL-2Rβ Tregs protect from lethal GVHD. (A) Schema of aGVHD mouse model. Survival curve (B) and aGVHD clinical scores (C) of mice treated with 1 × 106 of fTregs or oIL-2Rβ Tregs and injected with PBS or oIL-2 at a Tcon:Treg ratio of 1:1. Survival curves (D) and aGVHD clinical scores (E) of mice treated with oIL-2Rβ Tregs and injected with oIL-2 or PBS at a Tcon:Treg ratio of 5:1. Data are pooled from 3 independent experiments with a total of 10 to 15 mice per group. Error bars indicate standard error of the mean. P values are indicated when significant; ∗P < .05; ∗∗P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001. Survival curves were plotted using the Kaplan-Meier method and compared using a log-rank test. HSCT used BM transplantation depleted in T cells. Total body irradiation (TBI) was done without BM transplant. FACS, fluorescence-activated cell sorted; IP, immunoprecipitation; TCD, T cell depleted.
