Cytokine activation of NF-κB in CD34⁺CD19⁻ bone marrow cells. Human CD34⁺CD19⁻ bone marrow was purified and incubated for 18 hours at 37°C with each cytokine/peptide combination and EMSA was performed. (A) TNF-, (B) GM-CSF, (C) IL-3, and (E) a combination of GM-CSF, IL-3, SCF, and EPO activated NF-κB and its nuclear translocation could be blocked by the NF-κB NLS peptide. (D) M-CSF and G-CSF did not activate NF-κB. The purity of the CD34⁺CD19⁻ cells for experiments (A) through (E) was 99.1%, 98.7%, 96.8%, 95.6%, and 98.6%, respectively.