Neutrophil leucocyte chemotaxis: a simplified assay for measuring polarising responses to chemotactic factors

A method is described which greatly simplifies the screening of compounds which are potentially chemotactic for neutrophil leucocytes. Neutrophils isolated from blood by a standardised procedure are > 95% spherical in morphology. Addition of chemotactic factors in isotropic, non-gradient, concentrations induces the spherical shape to become polarised. The degree of polarity depends on the concentration of the factor used, as does the percentage of cells which become polarised. All compounds which induce a good response in assays measuring cell accumulation or orientation in gradients induced a consistent polarising response in non-gradient conditions with the cells held in suspension. The advantage of this simplified assay over methods currently in use are discussed.