MoAb to E-selectin inhibits the SDF-1–induced transmigration of LTC-IC through IL-1β–activated endothelial monolayer. Ten thousand CB-derived CD34⁺ cells were placed on the upper chamber of transwell plates that were covered with confluent monolayers of BMEC in the presence or absence of SDF-1 in the lower chamber and blocking MoAb to E-selectin in the upper chamber. After 24 hours, migrating cells from each condition were placed on MS-5 feeder layers to quantitate the number of migrated cobblestone area-forming cells (LTC-IC), which at week 5 were quantified by agarose assay. In the absence of SDF-1, there was a spontaneous migration of 14.0% ± 1.5% LTC-IC that was independent of SDF-1 and E-selectin. However, with the addition of SDF-1, an additional 17.6% ± 3.6% of the added LTC-IC migrated through IL-1β–activated endothelial cells. Blocking MoAb to E-selectin (10 μg/mL) almost completely inhibited (90.9% ± 16.6%) all SDF-1–induced migration of LTC-IC (N = 5,P < .007).