Regression line analysis of neutrophil chemotaxis

Polymorphonuclear leukocyte chemotaxis and chemokinesis, in the micropore filter assay, have been evaluated using Regression Line Analysis. The method discriminates between migration rate and the number of migrating cells by statistical comparison of the slope of the regression line and the γ -intercept, respectively. The derivation of this new method of assessment of cell migration is reported. This report also includes critical evaluation of the chemokinesis dose/ response curve and the directional component of chemotaxis. The effect of inhibitors of chemotaxis were evaluated using the new method. Colchicine was found to effect the directional component of chemotaxis, as indicated by decreased rate of locomotion in chemotaxis experiments, and had no effect on random migration and chemokinesis. Cytochalasin B had a general inhibitory effect upon cell locomotion by depressing the rate of random migration and chemotaxis. 1-Tosylamide-2-phenylethyl chloromethylketone (TPCK) had the apparent effect of uncoupling the receptor and effector mechanisms of chemotaxis, or altering the binding of the chemotactic ligand, since random migration was unaffected but the rate of chemotaxis and chemokinesis were depressed. Ionophore A23187 had a generalized inhibitory effect on the cell rate under all three conditions; however, at low concentrations it induced an increase in the number of migrating cells. These studies indicate that the method of regression line analysis is effective in differentiating in vitro the mechanisms of chemotaxis inhibition. The method may be used effectively in the assessment of defective neutrophil chemotaxis in disease states and may prove a useful adjunct to the study of cell locomotory mechanisms.