A, left column represents control macrophages from wild-type (WT) or iPLA2β-knock-out (KO) mice, and the right column represents macrophages subjected to FCL. In the 2nd and 4th rows, externalization of phosphatidylserine was visualized with Alexa-488-labeled annexin V. Total cells were determined from the light micrographs in the 1st and 3rd rows. B, percent of apoptotic cells was determined from annexin-positive and total cells in six fields of 1000 cells each. C displays macrophage caspase-3 activity. B and C, CON denotes control macrophages, and FCL denotes free cholesterol-loaded macrophages. Mean values ± S.E. are displayed (n = 6). Asterisk denotes p < 0.05 for WT versus KO.