The effects of activin-A and TGF-β on NK-cell CD69, NKp30, and NKG2D expression. NK cells from Figure 7A and 7C were stained with monoclonal antibodies against CD56, CD69, NKp30, and NKG2D. Ex vivo levels are compared with levels expressed after 3 days of culture and measured by flow cytometry. One representative donor of 6 is shown.