Blocking autocrine IL-15 increases cell death of myeloma cells induced by Fas-triggering, vincristine, or doxorubicin treatment but not that induced by dexamethasone.

RPMI 8226 and MC-Car cells were cultured in the absence or presence of anti–IL-15 mAb (5 μg/mL) for 48 hours and treated with CH11 mAb (10 ng/mL), vincristine (VCR, 2 μg/mL), doxorubicin (Doxo, 2 μg/mL), or dexamethasone (DEX, 1 μmol/L) for another 16 hours. The bars indicate the mean percentages of apoptotic cells ± SEM determined in 3 independent experiments.