Effect of inhibition of myosin IIA on NK cell IFN-γ secretion. (A) YTS cells incubated with DMSO vehicle control or blebbistatin for 30 min and then incubated in the presence or absence of 721.221 target cells at a 2:1 effector to target cell ratio for 0h (white), 4h (gray), or 22h (black). IFN-γ secreted into supernatant was measured by ELISA. Values shown are the mean ±SD of six independent experiments, each performed on a separate date. (B) IFN-γ secretion by vehicle- or blebbistatin-treated control donor eNK cells incubated in the presence of 721.221 target cells at a 2:1 effector to target ratio for 22h. In each experiment, the IFN-γ secreted by blebbistatin-treated eNK cells was normalized to the control (which is shown as 100%) and the values shown are the mean ±SD of three independent experiments, each performed on a separate date.