Persistence of acquired CCR7 receptors on NK cells. Kinetics of persistence of acquired CCR7 receptors (after Ficoll-Paque separation) from 3 independent experiments performed with different donor-derived NK cells. The percentage of CCR7⁺ NK cells was adjusted to 100% at time 0 hour, and the subsequent loss of acquired CCR7 relative to 0 hour was assessed over 72 hours. NK cells cocultured with Clone9.mbIL21 cells were used as negative controls and for background correction. The data are presented as median ± range (n = 3).