Fig. 4

Sequestration of the immune cells in the periphery greatly reduced CD4⁺ T cells including Foxp3⁺ Tregs in the white matter infarct. Sequestration of the immune cells in the peripheral lymph nodes was performed by FTY720 treatment from days 7 to 14 after stroke onset. A Representative immunohistochemical images for CD4 in vehicle-injected (Vehicle), FTY720-treated (FTY), and FTY720-treated and iVEC-transplanted (FTY + iVEC) groups at day 14. Nuclei were stained by Hoechst 33,342. Scale bar: 50 µm. B Quantification of CD4⁺ T cell number in each group at day 14. All data are expressed as mean ± SEM. n = 5 in each group. ^**p < 0.01. C Representative immunohistochemical images for Foxp3 in vehicle-injected (Vehicle), FTY720-treated (FTY), and FTY720-treated and iVEC-transplanted (FTY + iVEC) groups at day 14. Nuclei were stained by Hoechst 33342. Scale bar: 50 µm. D Quantification of Foxp3⁺ Treg number in each group at day 14. Note that the number of Foxp3⁺ Tregs in the FTY720-treated and iVEC-transplanted brain was significantly smaller than that of the vehicle-injected, FTY720-untreated brain, indicating that iVECs recruit Tregs from peripheral immune system to the ischemic infarct. All data are expressed as mean ± SEM. n = 5 in each group. ^***p < 0.001. These experiments were repeated three times, and similar results were obtained each time. Typical experiments are shown here