Fc-gamma- and complement receptor mediated elevation in the cytosolic calcium level in human neutrophils.
The effects of differently opsonized zymosan particles, acting solely at Fc-gamma or at complement receptors or at both, on the level of intracellular calcium ([Ca2+]i) in human neutrophils were studied. A biphasic, long-lasting increase in [Ca2+]i was seen in response to IgG-, C3- and fresh serum-opsonized zymosan particles in the presence of extracellular Ca2+. Unopsonized zymosan, acting mainly at CR3 failed to elevate [Ca2+]i. Addition of 1.4 mM EGTA reduced but did not abolish the rise in [Ca2+]i triggered by opsonized zymosan, indicating that Ca2+ is released from intracellular stores. EGTA changed also the kinetic patterns of Ca(2+)-responses possibly by indirectly affecting the extrusion of Ca2+ in neutrophils.
Tuominen
H
H
Department of Biochemistry and Pharmacy, Abo Academy University, Turku, Finland.
Leino
L
L
Akerman
K
K
D000943:Antigens, Differentiation / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D003176:Complement C3 / Q000494:pharmacology; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism*; D011951:Receptors, Complement / Q000378:metabolism*; D011961:Receptors, Fc / Q000378:metabolism*; D017452:Receptors, IgG; D015398:Signal Transduction / Q000187:drug effects; D015054:Zymosan / Q000494:pharmacology
D000943:Antigens, Differentiation; D003176:Complement C3; D007074:Immunoglobulin G; D011951:Receptors, Complement; D011961:Receptors, Fc; D017452:Receptors, IgG; D015054:Zymosan; D002118:Calcium