Figure 1.

Natural killer (NK) cell‐mediated killing of glioma stem‐like cells. (a) NK cell cytotoxicity: cell tracker violet‐labelled glioblastoma (GB) stem‐like cell (GSC) lines (targets) were co‐cultured with unlabelled, interleukin (IL)‐15 activated NK cells (effectors) for 5 h at effector : target (E : T) ratios as shown. Co‐cultures were then stained with a live/dead discriminator. The panel on the left shows identification of effector and target cells in the co‐culture (for gating purposes) and the panels to the right show death of the labelled target cells at the different E : T ratios. The zero hour control is included as background cell death of the GSC cells. The three graphs summarize data obtained using three GSC lines (GBM1, GBM4 and GBM20) and three different NK cell donors (coloured dots), with standard deviation from the mean. (b) NK cell specificity: cytotoxicity assays of IL‐15‐activated NK cells co‐cultured with a 1 : 1 mix of the GSC line (indicated) and neural progenitor cells (NP). The GSC and NP lines were labelled with different cell tracker dyes, allowing their fate in the assay to be determined separately. The flow cytometry plots show the percentage of dead GSC (here GBM4) and NP cells after zero and 5 h co‐culture with NK cells. The graphs summarize these data for assays containing the three GSC lines using NK cells from four separate donors (coloured dots), with standard deviation from the mean.