The supernatant was discarded and the wells were washed three times with PBS. After washing, 100 ml of 0.2% NBT were added and incubated for 1 h. The cells were then fixed with 100% methanol for 2e3 min and washed three times with 70% methanol
The supernatant was discarded and the wellswere washed three times with PBS. After washing, 100 ml of 0.2%NBT were added and incubated for 1 h. The cells were then fixedwith 100% methanol for 2e3 min and washed three times with 70%methanol