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. Author manuscript; available in PMC: 2013 Nov 15.
Published in final edited form as: J Immunol. 2012 Oct 12;189(10):4870–4880. doi: 10.4049/jimmunol.1201296

Figure 1. Lytic granule polarization precedes persistence at the NK immunological synapse prior to target cell death.

Figure 1

YTS GFP-actin (A, B, C) or NK92 GFP-tubulin (D, E) NK cells were loaded with LysoTracker Red (red) and incubated with CellMask labeled 721.221 (A, B, C) or K562 (D, E) target cells in the presence of SYTOX Blue (blue) to detect cell death. Conjugates were imaged by confocal microscopy at 1 frame per minute for 90–130 minutes. A. Representative YTS GFP-actin-721.221 conjugate is shown at 10-minute intervals for 120 minutes. Scale bar=1 um. B. Time to granule polarization in YTS GFP-actin NK cells as measured by lytic granule centroid distance to IS (mean 41.5±12 minutes, n=10). C. Time to initiation of 721.221 target cell apoptosis as detected by SYTOX Blue entry is shown for 10 conjugates (mean 61.5 ± 10 minutes, n=10). D. Time to granule polarization in NK92 GFP-tubulin NK cells as measured by lytic granule centroid distance to IS (mean 24.2 minutes, n=6). E. Time to initiation of K562 target cell apoptosis as detected by SYTOX Blue entry is shown for 10 conjugates (mean 54.2 minutes, n=6). All representative images and analyses shown are from 4 independent experiments. Error bars indicate SD.