Cross-linking of CD11b or CD18 signals release of localized Ca2+ from intracellular stores in neutrophils.
Cross-linking of antibodies bound to CD11b or CD18 on the neutrophil surface produced a large Ca2+ transient (max. approximately 500 nM). The major source for this Ca2+ rise (more than 81%) was from an intracellular Ca2+ store. After integrin cross-linking, the Ca2+ transient induced by N-formyl-methionyl-leucyl-phenylalanine (FMLP) was decreased, suggesting that both stimuli acted on the same Ca2+ store. Release from the Ca2+ store, induced by integrin cross-linking, was visualized as a 'cloud' of elevated Ca2+, which remained localized even in the presence of extracellular Ca2+. The generation of localized cytosolic Ca2+ signals by cross-linking integrin may be important for triggering localized cellular responses.
Petersen
M
M
Institute of Nephrology, University of Wales College of Medicine, Cardiff, U.K.
Williams
J D
JD
Hallett
M B
MB
D015703:Antigens, CD / Q000276:immunology*; D018845:CD11 Antigens; D018821:CD18 Antigens; D002118:Calcium / Q000276:immunology*; D003432:Cross-Linking Reagents; D006801:Humans; D016023:Integrins / Q000276:immunology; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000276:immunology; D009504:Neutrophils / Q000276:immunology*; D016028:Receptors, Leukocyte-Adhesion / Q000276:immunology
D015703:Antigens, CD; D018845:CD11 Antigens; D018821:CD18 Antigens; D003432:Cross-Linking Reagents; D016023:Integrins; D016028:Receptors, Leukocyte-Adhesion; D009240:N-Formylmethionine Leucyl-Phenylalanine; D002118:Calcium