Fig. 5.

Fresh noncytotoxic dNK fail to polarize the MTOC and perforin containing granules to the target cell contact site, as is done by the cytotoxic pNK, YTS, and IL-15-activated dNK. Confocal images of conjugates of a YTS cell (Left) a pNK cell (center left), a dNK cell (Center Right), and a dNK cell incubated 36 h in IL-15 (Right) with 721.221 cells. Staining shows α-tubulin (red), perforin (green), and F-actin (blue). Numbers at the bottom indicate the percentage of conjugates showing the MTOC polarized toward the target cell contact site.