rhFTVI treatment induces sLe^x expression on all Lin⁻ stem populations. (A) Cells sorted for Flk2⁻ CD34⁻ LT-HSCs and Flk2⁻ CD34⁺ ST-HSCs were treated either with rhFTVI or in buffer alone, as outlined in the Materials and methods section. After treatment, flow cytometric analysis for sLe^x expression (HECA-452) was performed. Plots are representative of n = 4 independent experiments. (B) The average percentage expression for each condition in (A) is represented. (C) The binding of E-selectin-hIg chimera was measured on sorted Flk2⁻CD34⁻ LT-HSCs and Flk2⁻CD34⁺ ST-HSC populations treated either with rhFTVI or in buffer alone using flow cytometric analysis. (D) Colony-forming capacities of sorted Flk2⁻CD34⁻ LT-HSCs and Flk2⁻CD34⁺ ST-HSCs were determined. Five hundred cells were either treated with rhFTVI or untreated and were cultured in methylcellulose in the presence of cytokines (SCF, IL-3, EPO, and GM-CSF) for 12 to 14 days. The number and composition of the colonies generated were counted and represented in the graph. BFU-E, erythroid burst-forming unit; CFU-GEMM, granulocyte-erythroid-megakaryocyte-macrophages colony-forming unit; CFU-GM, granulocyte-macrophage colony-forming unit.