Bone marrow cells from mice with severe combined immunodeficiency disease were virally transduced to express adenosine deaminase (ADA) to replace the mutant enzyme.
Bone marrow was depleted from red blood cells (RBC) by RBC lysis. The remaining cells were cultured (106/mL) for 24 hours in StemSpan serum-free expansion medium in the presence of murine stem cell factor (50ng/mL; SCF), human Flt3 ligand (10ng/mL ; Flt3-L), human interleukin-6 (20ng/mL; IL-6), murine IL-3 (10ng/mL), murine thrombopoietin (20ng/mL; Tpo), polybrene (4μg/mL), and PGK-ADA (0.4μg of viral p24 per 106 cells, corresponding to a multiplicity of infection [MOI] of 4–12).