A SIMPLE AND RAPID METHOD TO DETERMINE HEMATOPOIETIC GROWTH-FACTOR ACTIVITY

A rapid and simple colorimetric microassay method for the determination of hematopoietic growth factor activities was established. The assay was used to detect CSF-1, GM-CSF, and IL-3 activities. The assay was based on the metabolism of the tetrazolium dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide to formazan by metabolically active cells. Results obtained with the colorimetric microassay are comparable with those obtained with the soft agarose assay. Advantages of the colorimetric microassay include the conservation of reagents, the shorter incubation time for the experiment, the shorter assay time, and the ability to evaluate large numbers of samples. © 1990.