[The measurement of superoxide generation and eosinophil peroxidase (EPO) from eosinophils]

Eosinophils play an important role in the field of allergy, and release several kinds of granule proteins, leukotrien and superoxide. The most popular method to measure superoxide is utilizing SOD-inhibitable reduction of ferricytochrome c. And recently, the microplate reader enables us to measure superoxide generation from eosinophils more easily using this method. To measure superoxide, we must pay attention to obtain a high purity of eosinophils and not to damage cells. It is also possible to measure eosinophil peroxidase (EPO) using the microplate reader. We are measuring EPO with colorimetric assay using OPD (o-phenylenediamine). OPD is specific to EPO and has no cross reaction to myeloperoxidase. We, now have numerous methods to evaluate eosinophil function, so a selection must be made to select the most correct method.