Fig. 4: NK cell migration and cytotoxicity in 3-D collagen gels.

a Migration cell speed of fresh (blue) and cryopreserved (red) NK cells from n = 10 independent experiments from five subjects and five different expansions in a 3-D collagen gel. Each symbol represents mean ± se (measured in the x–y-imaging plane) from cells measured in five field of view, with ~80 cells (motile plus nonmotile) in each field of view. Migration cell speed and persistence is computed from on average n = 125 motile fresh cells and n = 12 motile cryopreserved cells for each subject and expansion (each data point). In total, n = 1248 motile fresh and n = 122 motile cryopreserved NK cells were measured. Paired (fresh vs. cryopreserved) data from each subject and expansion are connected by lines. a Cell speed (p = 0.076; two-sided nonparametric Wilcoxon signed-rank test for paired data). b Migration directional persistence (p = 1.0; two-sided nonparametric Wilcoxon signed-rank test for paired data). c Number of live K562 target cells (black line) in a representative experiment as a function of measurement time. Killing events are marked by green circles. The dashed green line indicates an exponential fit of the individual killing events, the black dashed line indicates an approximation using an exponential curve based only on the number of live targets at the beginning and the end of the measurement time. d Estimated killing efficiency (weighted mean ± se determined by bootstrapping) of fresh and cryopreserved motile NK cells against K562 target cells embedded in a 3-D collagen gel (p = 0.56; two-sided bootstrapping; n = 6 independent experiments from four subjects and three different expansions). e Estimated composite killing efficiency (weighted mean ± se determined by bootstrapping) of fresh and cryopreserved NK cells (considering both motile and nonmotile NK cells) against K562 target cells embedded in a 3-D collagen gel (p = 0.025; two-sided bootstrapping; n = 6). Note that the killing efficiency of the individual experiments is not shown in d, e as the reported mean values are weighted by the respective cell concentrations (see “Methods” section). Individual values are provided as a Source data file.