A rapid quantitative assay for activated neutrophils.

We present here a rapid, sensitive, and convenient assay for activated human PMNs based on detecting the decreased optical density (OD) of aggregated cell suspensions. This quantitative assay uses an ELIZA machine to measure OD changes, with time, of activated cells (5 X 10(5) cells/well) in microtiter plates. The assay is sensitive, detecting aggregation induced by as little as 0.0001 microgram/ml of LPS, or lymphokines in Con-A-activated supernatant diluted 1/500. The assay permits analysis of 400 separate PMN suspensions on the same day starting with less than 80 ml of blood.