Effect of FTY720 on in vitro transmigration of lineage-committed and pluripotent progenitors. (A) Lin^- cells transmigrating in response to SDF-1 (MS-5 conditioned medium) were analyzed for committed progenitors using a methylcellulose colony assay. When preincubated with FTY720 (100 nM every 3 hours) prior to transmigration, a significantly increased number of committed progenitors of both granulopoietic and erythroid lineages transmigrated (expressed as CFCs per well in the transwell assay). GM: granulopoietic colonies (CFU-GMs); B: erythroid colonies (BFU-Es); Mix: multilineage colonies (CFU-GEMMs); Total: total number of colonies. ^*P < .05; ^**P < .01; n = 4. (B) Total numbers of cobblestone areas of transmigrated Lin^- cells pretreated or not with FTY720 (100 nM every 3 hours) on FBMD-1 stromal feeders in fibronectin-coated 24-well plates. The number of cobblestone areas was scored after 5 weeks of incubation. ^**P < .01, n = 4.