Figure 4. Granzyme B and ⁵¹Cr release assay of ECs by resting and activated NK cells.

Granzyme B ELISPOT assay (4 h) of resting and TKD/IL-2-activated NK cells attacking HUVECs, EA.hy926 cells and HMECs (A). The effector to target (E∶T) ratios ranged between 10∶1 to 0.16∶1. The data represent mean values of at least 3 independent experiments. The differences in lysis of HUVECs compared to that of EA.hy926 cells and HMECs was significantly different *, p<0.05 at all E∶T ratios. Standard ⁵¹Cr release assay (4 h) comparing the lysis of HUVECs and HMECs by resting and TKD/IL-2-activated NK cells at effector to target ratios ranging from 10∶1 to 0.31∶1 (B). The data are from one typical experiment, therefore no statistical analysis has been performed.