title: Platelets stimulated by IgG-coated surfaces bind and activate neutrophils through a selectin-dependent pathway.
abstract: Blood platelets bind rapidly to foreign surfaces and interact with adsorbed proteins and neutrophil granulocytes. We demonstrate by use of luminol-amplified chemiluminescence under stirred and non-stirred conditions that platelets at IgG-coated surfaces amplify the neutrophil extracellular release of reactive oxygen species (ROS). The neutrophil response involved tyrosine phosphorylation, but was only in part induced by neutrophil F(c gamma)-receptor stimulation. The platelet mediated effects were contact-dependent since the respiratory burst was inhibited when the IgG-stimulated platelets were removed by filtration, but not when they were fixed in paraformaldehyde. Bodipyphallacidin-staining of filamentous actin (F-actin) revealed that an actin-dependent platelet adhesion supported the subsequent adhesion and spreading of neutrophils. The neutrophil ROS-response was lowered when the interaction between platelet P-selectin (CD62P) and neutrophil P-selectin glycoprotein ligand-l (PSGL-1 or CD162) was inhibited. The blocking of L-selectin (CD62L) or blocking of the interaction between platelet glycoprotein (Gp) IIb/IIIa and neutrophil complement receptor 3 (CR3) showed no effect. We conclude that platelet activation on immobilized IgG trigger a contact-dependent "frustrated" phagocytosis by neutrophils, associated with a release of toxic ROS.
authors.affiliation: Division of Applied Physics, Department of Physics and Measurement Technology, Biology and Chemistry, Linköping University, SE-581 83 Linköping, Sweden. jonwe@ifm.liu.se
authors.forename: Jonas
authors.initials: J
authors.lastname: Wetterö
authors.forename: Pentti
authors.initials: P
authors.lastname: Tengvall
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Bengtsson
mesh_terms: D001792:Blood Platelets / Q000276:immunology / Q000502:physiology*; D006801:Humans; D007074:Immunoglobulin G; D066298:In Vitro Techniques; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000097:blood; D009504:Neutrophils / Q000502:physiology*; D019007:P-Selectin / Q000097:blood*; D015539:Platelet Activation / Q000502:physiology*; D010973:Platelet Adhesiveness / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013499:Surface Properties
chemical_list: D007074:Immunoglobulin G; D008562:Membrane Glycoproteins; D019007:P-Selectin; C084882:P-selectin ligand protein; D017382:Reactive Oxygen Species