The CD94^highCD56^dim NK-cell subset possesses higher STAT4 phosphorylation than the CD94^lowCD56^dim NK-cell subset. (A-B) Purified CD94^highCD56^dim (Hi) and CD94^lowCD56^dim (Lo) NK-cell subsets were cultured in media in the presence or absence of costimulation with rhIL-12 (10 ng/mL) and rhIL-15 (100 ng/mL) for 30 minutes. Lysates from these cells were used to determine the level of STAT5, and STAT3 (A) or STAT4 (B) phosphorylation by Western blotting. Assessment of β-actin or total STAT4 was included to control for protein loading. (C) CD94^highCD56^dim (Hi) and CD94^lowCD56^dim (Lo) NK-cell subsets were treated in media with or without rhIL-12 alone or costimulation by IL-12 and IL-18 for 30 minutes. Lysates from the harvested cells were used to detect STAT4 phosphorylation. β-Actin was included to control for protein loading. Data in panels A to C are representative of at least 3 experiments with similar results.