Flow-cytometric measurements of the transmembrane potential, the surface charge density and the phagocytic activity of Guinea pig macrophages after incubation with lymphokines.

The effects of lymphokines on guinea pig peritoneal macrophages were measured via flow cytometry utilizing the three-parameter FLUVO-METRICELL flow cytometer. On the basis of cell volume three distinct macrophage populations could be distinguished. Three to 5 min after starting the incubation with lymphokines a hyperpolarization of all three macrophage populations took place which was followed by depolarization. After 60 min the transmembrane potential reached again its control values. The negative charge density of the cell membrane decreased shortly after beginning of the incubation to 70-80% of the initial value and then remained unchanged for the following 120 min. The phagocytic activity of the macrophages was diminished during the depolarisation phase but increased over control values after restoration of the transmembrane potential.