Abstract
We have been studying the differentiation-inducers and their action mechanisms for ML-1 cells derived from a patient with acute myeloblastic leukemia. The NBT test measuring superoxide anion produced by activated granulocytes or macrophages is widely used as one of the assays for differentiation of myelogenous leukemia cells. Instead of counting cells with the insoluble blue formazan dye by the reduction of nitroblue tetrazolium (NBT) using a microscope, we tried to establish a quantitative colorimetric assay using a 96-well microscope and a spectrophotometer for the exclusive use of 96-well microscope. The conditions of the assay including cell number, incubation time, time for the culture with test samples etc. were determined. The logarithmic values of the optical density of NBT reduced by differentiated ML-1 cells were directly proportionated to the percentage of NBT-positive cells determined with a microscope. By using this new method, it would be possible to measure the differentiation inducing activity of various inducers for ML-1 cells objectively and quantitatively.
