Figure 3
Activation of natural killer cells with interleukin-15 restores specific cytolysis of chemotherapy-resistant Ewing sarcoma cells to levels similar to those observed for chemotherapy-sensitive cells. Cytotoxic activity of IL-15-activated natural killer cells was evaluated in 51Cr release assays using chemotherapy-sensitive (grey) and -resistant (black) Ewing sarcoma cell lines TC71 (grey dots), SK-ES-1 (grey squares) and SK-N-MC (grey triangles) respectively STA-ET2.1 (black squares), CADO-ES (black dots) and IOR/BER (black triangles) as target cells. K562 and EBV B-LCL cell line 107 were used as positive and negative control respectively. Results are expressed as the mean ± SEM percentages of specific lysis obtained in at least four independent experiments using different healthy donors.