Functional activity of human NK cells from reconstituted NSG mice in comparison to human adult or CB NK cells. Degranulation, a surrogate marker for cytotoxicity, and cytokine production were assessed by surface CD107a and intracellular IFN-γ staining in response to ex vivo stimulation with medium, the erythroleukemia cell line K562, the T-cell lymphoma cell line CEM, and the monokines IL-12 plus IL-15 (IL-12/15). One representative staining (A) and composite data (B) of 12 mice in 3 experiments are shown. In the composite data human NK-cell reactivity of reconstituted NSG spleens was compared with 3 adult PBMC samples. In addition, the function of the human NK-cell subsets CD56^brightCD16⁻, CD56^dimCD16⁺ and NKp46⁺CD56⁻ from human adult (PBMC), hu-NSG (C) mice or CB (CBMC in panel D) were compared for degranulation. Composite data of 3 (C) and 6 (D) experiments are shown. Numbers in plots represent frequencies within gates.