iNKT2 and iNKT17 cells protect from GVHD, whereas iNKT1 cells have no suppressive potential. (A) BALB/c recipient mice were irradiated with 2 × 4.4 Gy, followed by transplantation of 4 × 10⁶ TCD-BM cells and 1.0 × 10⁶ Tcon from luc⁺ FVB/N donor mice. In addition, 5 × 10⁴ FACS-sorted iNKT1, iNKT2, or iNKT17 cells from FVB/N donors were transferred together with the graft. Shown are the survival curve (left graph), weight (middle graph), and GVHD score (right graph). Data are pooled from 3 independent experiments with a total of 15 mice per group (except irradiation control, n = 10). Error bars indicate standard error of the mean. (B) BALB/c recipient mice were transplanted as aforementioned, and 1 × 10⁴ FACS-sorted iNKT1, iNKT2, or iNKT17 cells from FVB/N donors were transferred together with the graft. The survival graph is depicted on the left; the data are pooled from 3 independent experiments with a total of 20 mice per group (except total body irradiation [TBI, n = 10] and BM [n = 15]). For weight (middle graph) and GVHD score (right graph), data are pooled from 2 independent experiments with 10 mice per group. Error bars indicate standard error of the mean. (C) Serum Th1/Th2 cytokine levels (IFN-γ, TNF-α, IL-2, IL-6, IL-18, IL-5, and IL-13) at day 7 from transplanted mice are shown (n = 6-8 in each group). P values are indicated when significant. *P < .05; **P < .01; ***P < .001. BMT, BM transplantation.