Binding of LFA-1 to ICAM-1 results in accumulation of talin, actin, Arp2/3, vinculin and WASP. Ex vivo, interleukin-15 (IL-15)–, or IL-2–activated splenic natural killer (NK) cells were incubated with intercellular adhesion molecule-1 (ICAM-1; IC-1)– or poly-L-lysine (PLL)–coated beads as indicated. Cells were fixed, permeabilized, and stained for talin (A), actin (B), Arp2/3 (C), vinculin (D), or WASP (E). In all panels shown except actin, cells were stained with primary antibody followed by an Alexa Fluor 488 secondary antibody. Actin was detected with rhodamine phalloidin. Slides were mounted with VectaShield mounting medium (Vector). At least 60 images per condition (original magnification ×400) were collected by Nikon C1-si confocal microscope (100×/1.45 numeric aperture oil objective) using sequential scanning and imported into Volocity software. Images were merged in Volocity and exported as .TIF files. Fluorescence intensity of staining at the contact site between an NK cell bound to an (▬) ICAM-1– or (▭) PLL–coated bead was expressed as a percentage of total fluorescence intensity of staining found within the cell and shown to the right of the corresponding panel of confocal images. Error bars indicate SEM, n = 10 per condition. ***P < .005, **P < .01, and *P < .05 compared with corresponding PLL condition.