Fig. 3.

The effect of host secretory S1P on donor T-cell migration and differentiation after allo-BMT. Lethally irradiated WT and Sphk1^−/− mice were transplanted with 5 × 10⁶ TCD-BM isolated from FVB donors plus 0.5 × 10⁶ total T cells isolated from β-actin-luciferase transgenic FVB mice (n = 10 mice/group). T-cell migration was monitored using bioluminescent imaging (BLI). Macrophotos show BLI for A the total body over time and C individual organs in a region of interest (ROI) summary (B, D). Lethally irradiated WT and Sphk1^−/− mice (H2^b) were transplanted with 5 × 10⁶ TCD-BM (Thy1.2⁺) plus 0.75 × 10⁶ total T cells (Thy1.1⁺) isolated from FVB mice (H2^q). Two weeks after allo-BMT, the spleens and livers of the recipients were collected and analyzed by flow cytometry (n = 8–11 mice/group). The numbers of infiltrated donor cells, representative dot plots, and the average levels of IFN-γ, IL4/5, IL-17, and Foxp3 on gated donor CD4⁺ or CD8⁺ T cells from E, F spleens and G, H livers are shown. “BMA” in the summary graph indicates BM alone. The experiments were repeated 2 times independently, and the combined data are presented. Nonparametric Mann‒Whitney U test (C) was performed to compare between groups. Statistical data are presented as the mean ± 1 SD, and significance was determined by Student’s t-test. *P < 0.05, **P < 0.01, ***P < 0.001 and ****P < 0.0001