Murine il 3

FDCP-mix cells were cultured in IMDM medium (PAA Lab, Colbe, Germany) supplemented with horse serum (Gibco, Darmstadt, Germany) and murine IL3 (10 ng/ml; R&D Systems, Wiesbaden, Germany). Kasumi-1 cells were cultured in RPMI medium (Gibco) supplemented with 20% FCS (fetal calf serum; PAN Biotech, Aidenbach, Germany). Lin− mBM cells were cultured in StemSpan medium (StemCell Tech, Cologne, Germany) supplemented with murine IL3 (10 ng/ml), murine IL6 (50 ng/ml) and murine stem cell factor (50 ng/ml). Human CD34+ cells were cultured in StemSpan medium supplemented with human IL3 (10 ng/ml), human SCF (20 ng/ml), human IL6 (20 ng/ml), human FLT3L (20 ng/ml), human thrombopoietin (20 ng/ml) and human granulocyte–macrophage colony-stimulating factor (20 ng/ml). Lentiviral particles were produced using the calcium phosphate co-precipitation method. Briefly, 5.8 × 10⁶ HEK-293 T cells were seeded in a 10-cm² tissue culture dish (Cellstar, Frickenhausen, Germany) and incubated at 37 °C in a humidified CO₂ incubator. Next day, the co-transfection mix was prepared and distributed over the cells. Fresh medium was replenished 6 h after transfection. Finally, the viral supernatants were collected 48 h after transfection. Viral particles were then transduced into the cells on retronectin (50 μg/ml)-coated non-tissue culture plates.