Combination of α-GalCer-lipo administration plus low-dose Tregs suppresses GVHD. BALB/c recipient mice undergoing irradiation at 8.8 Gy received 5.0 × 10⁶ T cell–depleted BM cells (BMCs) and 1.0 × 10⁶ negatively isolated Tcons obtained from C57BL/6 donor mice. CD4⁺Foxp3^GFP+ Tregs were isolated from C57BL/6 background Foxp3^GFP transgenic mice and injected together with Tcons at 1:10 Treg/Tcon ratio. Immediately after cell infusion, Ctrl-lipo or α-GalCer-lipo was injected via tail vein (10 μg/kg). (A) Mean ± standard error of the mean (SEM) of percentage change in body weight from baseline (day before BMT). (B) Mean ± SEM of GVHD score at indicated time points. (C) Survival curve of the recipients in each group. P values calculated by log-rank test between 2 indicated groups. Pooled data of 4 independent experiments are shown. ***P < .001, ****P < .0001. ns, not significant; TBI, total-body irradiation alone.