The low-affinity Fc receptor FcγRII is arranged in discrete nanoclusters at macrophage surfaces. (A and B) TIRF and dSTORM images of FcγRII at the surface of human macrophages seeded onto PLL- (nonactivated) or hIgG-coated slides for 10 min (A) or 30 min (B) and stained with a fluorescently labeled specific antibody. Bars, 5 µm. Regions delineated by the white squares are zoomed-in and shown with corresponding density maps, binary maps, and Ripley’s K analysis. Bars, 1 µm. (C–E) Nanocluster areas (C), density (D), and percentage of localizations in nanoclusters (E) for FcγRII under nonactivated (black) or hIgG-activated (gray) conditions at 10 or 30 min were calculated as in Fig. 1. Horizontal lines and error bars represent mean ± SD. Data are from a minimum of 15 cells from three independent donors. ns, not significant; *, P < 0.05; **, P < 0.01; ****, P < 0.0001; two-tailed t test assuming unequal variance.