A wave of elevated intracellular free calcium spreads through human neutrophils during phagocytosis of zymosan.
The cytosolic concentration of free calcium ([Ca2+]i) plays an important role in the control of many neutrophil functions. In this study, we characterize the early rapid subcellular changes in [Ca2+]i that occur in adherent neutrophils during phagocytosis of zymosan particles, using both dual- and single-excitation wavelength Fura-2 ratio imaging. We observed a wave of elevated cytosolic calcium that began shortly after zymosan contact and propagated from the region of neutrophil contact with the zymosan throughout the cell at a rate of approximately 17 microns/s at 31 degrees C. The wave was initiated by both opsonized and unopsonized zymosan and occurred independently of extracellular calcium. Multiple characteristics of the [Ca2+]i signal (including the absolute and regional [Ca2+]i and wave properties such as amplitude, frequency, duration, and topography) may be responsible for the differential regulation of cellular functions in the neutrophil.
Schwab
J C
JC
Department of Internal Medicine, University of Virginia Health Sciences Center, Charlottesville 22908.
Leong
D A
DA
Mandell
G L
GL
D002118:Calcium / Q000378:metabolism / Q000502:physiology*; D003600:Cytosol / Q000378:metabolism / Q000502:physiology; D006801:Humans; D007424:Intracellular Fluid / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism / Q000502:physiology*; D010587:Phagocytosis / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D015054:Zymosan / Q000276:immunology*
D015054:Zymosan; D002118:Calcium