LFA-1 but not CD16 engagement induces lytic granule convergence in NK cells. Fixed-cell confocal microscopy of YTS-CD16 (A) and eNK (B) cells incubated with S2, S2 antiserum, S2-IC1, or S2-IC1 antiserum cells. The NK cells appear by themselves when incubated with uncoated S2, as they did not adhere to the NK cells. Quantitative analyses of lytic granule distance from the MTOC are shown as a feature of the degree of granule convergence in YTS-CD16 (C) and eNK (D) cells. Data represent 30 cells per group, from three independent experiments for YTS-CD16 cells and three healthy donors for eNK cells. Gray points in each condition indicate the representative conjugates shown in A and B. Error bars show ± SD. **, P < 0.01; ***, P < 0.001; ****, P < 0.0001; ns, not significant.