Activated NF-κB measured by flow cytometry in human CD4⁺ peripheral T cells ([A] unstimulated, [B] stimulated) and CD34⁺CD19⁻ bone marrow cells ([C] unstimulated, [D] stimulated). Stimulated cells were incubated with 25 ng/mL PMA and 1 μg/mL ionomycin for 1 hour at 37°C before NF-κB analysis. Activated NF-κB is a black line and the background isotype antibody binding is a gray line for each sample. The monoclonal antibody used in these experiments has been shown to be specific for the NF-κB nuclear localization region, which is detected only if NF-κB is activated. The CD4⁺ T cells and CD34⁺CD19⁻ bone marrow cells were more than 97% and more than 99% pure, respectively.