Volume, conductivity, and scatter changes of activated polymorphonuclear leukocytes: an estimation by Coulter Counter STKS analyzer.

Suspensions of phorbol myristate acetate-activated polymorphonuclear leukocytes were analyzed with a Coulter Counter STKS hematological analyzer. Phorbol myristate acetate activation induced an increase in polymorphonuclear leukocyte volume and conductivity, while scatter was unchanged. Phorbol myristate acetate-activated neutrophils in a suspension containing nitroblue tetrazolium showed increased scatter. The rise in scatter was phorbol myristate acetate dose dependent, completely inhibited by diphenylene iodonium and partially by dimethyl sulfoxide, two inhibitors of NADPH oxidase. Zymosan-activated polymorphonuclear leukocytes were notably larger with a characteristic position on discriminant function 1 display (volume versus scatter) of the analyzer. Volume and conductivity changes were seemingly inexplicable features of phorbol myristate acetate activation. The rise in scatter was produced by cytoplasmic precipitation of reduced nitroblue tetrazolium and thus by O2-generation in phorbol myristate acetate-activated neutrophils. Zymosan phagocytosis was responsible for the notable rise in polymorphonuclear leukocyte volume. The analysis of activated polymorphonuclear leukocytes by Coulter Counter STKS may provide useful information on their activation and a pragmatic approach for studying function.