A flow cytometric method to measure shape change of human neutrophils.

1. We report a flow cytometric method in which changes in forward angle light scatter are shown to correlate with microscopically evaluated shape change in stimulated human neutrophils. Neutrophil movement and chemotaxis is conventionally measured using Boyden chambers, which is a laborious and exacting technique. Microscopic scoring of neutrophil shape change has been shown to correlate well with Boyden chamber measurements, and although less laborious, still requires manual counting. 2. We now show that measurement of forward angle light scatter in a benchtop flow cytometer correlates closely with microscopic evaluation of neutrophil shape change in dose-response stimulation experiments with leukotriene B4, N-formyl-methionine-leucine-phenylalanine or interleukin-8. The relationship between shape change and increased forward angle light scatter was confirmed using the fluorescence-activated cell sorter to separate partially stimulated neutrophils, followed by reanalysis by flow cytometry and microscopic examination. 3. This flow cytometric method provides a convenient, rapid and objective measure of neutrophil responses to external stimuli.