Sdf 1b

GPR15 expression was induced on sorted CD4 þ GPR15 À T cells as described previously (15) . After 5 days, CD4 þ GPR15 À and CD4 þ GPR15 þ T cells were sorted and subjected to a migration assay using Transwell chambers (Corning). SDF-1b (50 ng/mL; PeproTech)/IMDMc was added to the bottom chamber. GPR15 À or GPR15 þ cells (5 Â 10 5 ) were added to the upper insert and incubated for 4 hours at 37 C, after which, the migrated cells were collected from the lower chamber and counted. Migration index was calculated as the ratio of migrated cells toward SDF-1b in comparison with cell migrated to media alone.

CB-MNCs and Jurkat cells were exposed to DMSO, and a chemotaxis assay was performed as described previously (15). Briefly, 650 µl/point of prewarmed 0.5% bovine serum albumin (BSA) containing RPMI-1640 medium, with 100 ng/ml SDF-1b (PeproTech Inc., Rocky Hill, NJ, USA) for CB-MNCs or various concentrations of SDF-1b (1 to 2,000 ng/ml) for Jurkat cells, was added to the lower chamber of the Costar Transwell 24-well plate (Corning Inc., Corning, NY, USA). Cell suspensions were distributed to the upper chambers and incubated at 37°C, in 95% humidity with 5% CO 2 for 3 h. Cells from the lower chambers were collected, and cell number was scored by FACSCalibur (BD Immunocytometry Systems). Results are demonstrated as a percentage of the cells in reference to the number of the cells in the input wells. In some experiments, cells from the lower chambers were seeded in methylcellulose and stimulated to grow CFU-GM and BFU-E colonies.