Incubation of human mobilized peripheral blood (MPB) CD34⁺ cells. Incubation of human mobilized peripheral blood (MPB) CD34⁺ cells for 48 to 72 hours with IDB up-regulates CD9 expression compared with MPB CD34⁺ cells incubated without IDB, but homing IDB-treated cells in NSG mice is not improved. (A) Flow cytometric analysis of CD9 expression on human MPB CD34⁺ cells cultured for 48 hours in the absence (left panel) or presence (right panel) of IDB. (B) Summary of the CD9 MFI of human MPB CD34⁺ cells at baseline and after culture in the presence or absence of IDB for 24, 48, or 72 hours. (C) Summary of homing studies after 48 hours of incubation with IDB. Human MPB CD34⁺ cells were exposed to IDB for 48 hours before transplantation into NSG mice; cells in the control group were cultured without IDB. In both groups homing of the human cells to the mouse bone marrow was measured by flow cytometry using human CD45 antibodies 18 hours after transplantation (■, Donor 1; ●, donor 2). (D) Summary of homing studies after 72 hours of incubation with IDB. Human MPB CD34⁺ cells were exposed to IDB for 72 hours before transplantation into NSG mice; cells in the control group were cultured without IDB. In both groups, homing of the human cells to the mouse bone marrow was measured by flow cytometry using human CD45 antibodies 18 hours after transplantation (■, Donor 1; ●, donor 2).