Culturing HEK293, HEK293T, and CD34+ Cells

HEK293 and HEK293T were cultured in Dulbecco’s Modified Eagle’s Medium (Lonza, Basel, Switzerland). Culture medium was supplemented with 10% fetal bovine serum, 100 U/ml penicillin, 100 μg/ml streptomycin and 250 μg/ml L-glutamine. Human cord blood was obtained from Aarhus University Hospital. CD34⁺ cells were purified from umbilical cord blood using EasySep Human Cord Blood CD34 Positive Selection Kit (STEMCELL Technologies, Grenoble, France) and cultured in StemSpan serum-free expansion medium (STEMCELL Technologies) supplemented with human early-acting cytokines (PeproTech, Rocky Hill, NJ) including stem cell factor (SCF) 100 ng/ml, Flt3 ligand (Flt3-L) 100 ng/ml, thrombopoietin (TPO) 50 ng/ml, and interleukin 3 (IL-3) 20 ng/ml and enhancer of self-renewal UM171 50 nM (STEMCELL Technologies). Induced pluripotent stem cells, described in a previous publication (Kang et al., 2015 (link)), were cultured using TeSR-E8 medium (STEMCELL Technologies) on Vitronectin XF (STEMCELL Technologies) coated culture dish. All cells were cultured at 37°C and 5% (vol/vol) CO₂.