Fucosylation of Flk2⁻CD34⁻ LT-HSCs and Flk2⁻CD34⁺ ST-HSCs improves engraftment in primary and secondary recipients differentially. Lethally irradiated Ly5.1 mice were transplanted with ∼500 to 1000 rhFTVI-treated (red) or buffer-treated (blue) Flk2⁻CD34⁺ (left panels in (A) and (B) or Flk2⁻CD34⁻ (right panels in [A] and [B]) HSCs from Ly5.2 donor BM. BM from transplanted recipient mice was then investigated at the indicated (A) short-term periods and (B) longer-term periods for the percentage of donor cell contribution to total BM cells. Each data point represents the mean ± SEM (*P = .033, **P = .002, and ***P < .001). (C) A representative analysis of donor cell engraftment for both Flk2⁻CD34⁺ HSCs (left panel) and Flk2⁻CD34⁻ HSCs (right panel), either buffer-treated (blue) or rhFTVI-treated (red), is shown. (D) Assessment of the contribution of donor cells to the blood lineage cells in the recipient mice following transplantation of buffer-treated and FTVI-treated Flk2⁻CD34⁺ and Flk2⁻CD34⁻ in primary recipient mice. BM was first gated using flow cytometry for the donor cells (CD45.2), and further analysis for blood lineage phenotypes was assessed. For myeloid cells, granulocytes (Gr-1⁺ and CD11b⁺) and monocytes (Gr-1⁻ and CD11b⁺) were assessed, and for lymphoid cells, B-cell (CD19) and T-cell (CD3) subsets were assessed. CD34 was used as a stem cell marker. All data presented are means ± SD of >5 mice from each group. (E) Flk2⁻CD34⁺ HSCs were collected from primary transplanted mice and transplanted into irradiated secondary recipients. At the indicated times following transplantation, BM was assessed for the percent of the donor cells in the recipient mouse, and statistical analysis was performed using the unpaired t test (*P = .033).