Phagocytosis by Human Macrophages Is Accompanied by Changes in Ionic Channel Currents

• Published in: The Journal of cell biology Vol. 106; no. 6; pp. 1873 - 1878
• Main Authors: Ince, C., J. M. C. C. Coremans, Ypey, D. L., Leijh, P. C. J., Verveen, A. A., van Furth, R.
• Format: Journal Article
• Language: English
• Published: New York, NY Rockefeller University Press 01.06.1988; The Rockefeller University Press
• Subjects: Biological and medical sciences; Cell lines; Cell membranes; Cell physiology; Cells; Electric Conductivity; Electric current; Electrophysiology; Endocytosis; Fundamental and applied biological sciences. Psychology; Humans; In Vitro Techniques; Ion channels; Ion Channels - physiology; Latex; Macrophages; Macrophages - physiology; Membrane potential; Molecular and cellular biology; Opsonin Proteins; Phagocytes; Phagocytosis; potassium; Receptors, Fc - physiology; Human; Albumin; Electrophysiology; IgG; Embedding; Patch clamp method; Ionic current; Latex; Particle; Membrane; Current; Potassium; Phagocytosis; Macrophage
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.106.6.1873

The present study has shown that changes in ionic channel currents accompany the phagocytosis of particles by mononuclear phagocytes. The patch-clamp technique in the cell-attached configuration was applied to human monocyte-derived macrophages to measure the activity of single transmembrane ionic channels in intact cells. During such measurements, IgG-opsonized and non-opsonized latex particles were offered for phagocytosis under continuous video-microscopical observation. Single particles were presented to the phagocytes at a membrane location some distance from that of the patch electrode. After a lag period following particle attachment, enhanced inward and outward time-variant single channel currents coinciding with particle engulfment were observed. On the basis of current-voltage characteristics and membrane potential measurements, the outward-directed channels were identified as K+channels. Phagocytosis was also accompanied by slow transient changes in background membrane currents, probably due to changes in the membrane potential of the phagocytosing cell. Phagocytosis of IgG-coated latex particles differed from phagocytosis of uncoated or albumin-coated particles by a shorter lag time between particle attachment and the onset of enhanced ionic channel activity.