Effect of AHR inhibition on NK-cell function. (A-C) NK cells cell expanded using FC21 feeder cells for 2 weeks. Following the expansion, NK cells were treated overnight with SR-1 (1 μm) or DMSO (control). NK cells were then cocultured with calcein-labeled K562, SJGBM2, or HS578T cells at various effector to target (E:T) for 4 hours. The calcein release in the supernatant was used to determine mean specific lysis. (D-E) NK cells were expanded using FC21 cells for 2 weeks with SR-1 (1 μm) or DMSO (control). The expanded NK cells were cocultured with calcein-labeled tumors: K562 or SJGBM2 cells at E:T for 4 hours.