FOXP3 and Stroke: Moreover, when treated with FTY720 from days 7 to 14 after stroke onset, the number of Foxp3+ Tregs in the iVEC-transplanted brain was significantly smaller than that of vehicle-injected brain of the FTY720-untreated animal (Fig. 4C, D), indicating that iVECs recruit Tregs from peripheral immune system to the ischemic infarct.