EBI3 and gp130 protein expression is increased in human primary NK cells in response to receptor- and cytokine-mediated stimulation. Human primary CD56bright and CD56dim NK cells were isolated from blood obtained from healthy blood donors and (A, B, D, and E) either left unstimulated or stimulated with IL-12 and/or IL-18 for 24 h or (C) primed with IL-2 for 24 h before being stimulated with plate-bound isotype-matched control Ig or anti-NKG2D mAb for 24 h. (A–C) Intracellular EBI3 and p35 protein expression was analyzed by flow cytometry. (A) Data are representative of three different donors. (B and C) Data show mean ± SD from three different donors. (D) Surface gp130 expression and (E) intracellular IL-12Rβ2 expression was examined by flow cytometry. Data are representative of three different donors. Statistical analysis was performed by two-tailed unpaired Student’s t test (*P < 0.05, **P < 0.01, and ***P < 0.001).