Effect of siRNA-mediated knockdown of IκBζ in human NK cells. To assess the role of IκBζ in IFN-γ production, human NK cells were nucleofected with siRNA targeting IκBζ (30nM) or siControl (30nM). After nucleofection, the cells were stimulated with recombinant IL-12 and IL-18 (10 ng/mL each). (A) Protein expression for IκBζ and IFN-γ. IκBα, actin, and IL-8 are also shown as controls. (B) Gene expression profiles for IFN-γ, IκBα, and IL-8 in IκBζ knockdown cells. The immunoblot is representative of 7 independent experiments. Bar values represent the mean ± SEM for 5 to 7 experiments. *Values in the nondetectable range. **P < .05 vs controls. ***P < .005 vs controls. RCN indicates relative copy number.