The quantification of neutrophil orientation and migration under agarose — a new method for detecting directed and random movements

Abstract

Polymorphonuclear (PMN) granulocyte migration under agarose has been examined quantitatively with regard to measurement of the distance to the leading front cells, the location of maximal cell density and the limits for 50% of the migrating cells, and assessment of the degree of orientation of migrating neutrophils after fixation and staining. It was found that two cytotaxins, bacterial factors from E. coli (BF) and serum, both elicited directed and stimulated migration during the first hour of incubation. Thereafter, a continuous decrease of cell orientation and the distance to the boundary of the cell front occured, with some differences between the cytotaxins. Leukocytes were also incubated with vinblastine and cytochalasin B, serving as models for selective impairment of migration coordination and locomotive ability. With vinblastine, the foremost PMNs did not migrate as far as untreated cells, but treatment did not influence the distance migrated by most of the cells although the PMNs moved in an disoriented manner. Cytochalasin B impaired forward movement of the cells while orientation was well preserved. It is suggested that the agarose assay inexpensively and easily assesses whether chemotaxis or chemokinesis is occuring. Estimation of the degree of orientation of migrating neutrophils was a particularly valuable variable not previously used for this purpose. Two unrelated cytotaxins elicited chemotactic followed by chemokinetic migration, emphasizing that both types of movement may occur in a time-associated manner during incubation.