The degranulation (CD107a expression) of purified IL-2-stimulated (100 U/ml for 4 days) NK cells in response to immobilized MICA-129Met-Fc and MICA-129Val-Fc, and as negative control, OVA-Fc fusion proteins was determined by flow cytometry after 1 h (n = 3). Displayed are means and SD of the MFI (left panel) and the percentage of CD107a+ cells (right panel). Differences between MICA-129Met-Fc- and MICA-129Val-Fc-induced NK-cell degranulation were analyzed by two-way ANCOVA adjusted for MICA protein concentration, and the respective P-values are indicated. 