FTY720 inhibits HPC mobilization by CXCR4 antagonists but not G-CSF. (A) Groups of 6 mice were treated with FTY720 or placebo 14 hours before being killed. PB was collected and analyzed for total WBCs and T cells by flow cytometry. The mean and SD of 6 animals is shown. *P < .05. (B) Thymi collected from mice treated as in panel A were stained for S1P1 using immunohistochemistry. Representative fields of view obtained using SPOT Version 4.6 software and a SPOT RTKE camera attached to an Olympus BX40 microscope with a UPlanFl 40×/0.75 lens are shown. Original magnification was 400×. (C-F) Groups of 6 mice were treated with FTY720 or placebo 14 hours before administration of TC14012 (C-D) or G-CSF (E-F). Mice mobilized with G-CSF also received FTY720 each day during the mobilization protocol. WBC counts (C and E) were performed on blood collected by cardiac puncture. CFUs (D and F) were enumerated using semisolid cultures and the number of CFUs/mL was calculated using total WBCs. Each dot represents data from a single animal and the bar indicates the mean for the cohort. Representative experiments are shown. n = 3 for panels C and D and n = 2 for panels E and F. *P < .05 compared with control; #P < .05 compared with TC14012 alone.
