Effect of a 24 h exposure to 2.5 nM PMA on NK cell-surface protein expression. A) CD11a. Dashed line = IgG isotype control, thin solid line = control NK cells, bold line = PMA treated cells, y-axis is cell number, and the x-axis is fluorescence intensity. B) CD16. C) CD18. D) CD56. Representative histograms are shown. Results were replicated in NK cells prepared from three separate donors, n=3.