I want to count killing percentage by using MTT assay. I incubated spores with macrophage in time course and used MTT dye for overnight, dye concentration 0.1 mg/ml.
My question is that I want to use the formula below but the problem is when I used, I got negative result. Does anybody used before?
Percent killing = 1 - (A 570 of fungi incubated with white blood cells/A570 of. fungi incubated without white blood cells) x 100