Differential Secondary Reconstitution of In Vivo-Selected Human SCID-Repopulating Cells in NOD/SCID versus NOD/SCID/γ chain^null Mice

Figure 2

Overview of primary and secondary reconstitution experiments in NSG versus NOD/SCID mice. Human umbilical cord blood CD34⁺ cells were transduced with a GALV-pseudotyped oncoretroviral vector, SF1-MGMT^P140K-IRES-EGFP (MO1=5) and transduced cells transplanted into sublethally irradiated (300 cGy) NSG or NOD/SCID mice. One month after transplantation, cells were selected in vivo with 2 cycles of 20 mg/kg 6BG followed one hour later with 5 mg/kg BCNU. At 4 months after transplantation, the bone marrow was harvested and analyzed for the presence of human cells by flow cytometry. Bone marrow cultures were prestimulated in IL-6 and SCF for 48 hours and then equal numbers of human bone-marrow cells were transplanted into secondary recipient NSG and NOD/SCID mice. At 2 months after transplant, the secondary mice were analyzed for the presence of human cells via flow cytometry.