[Analysis of platelet-derived factors that modulate functions of polymorphonuclear leukocytes].
Interactions between platelets and polymorphonuclear leukocytes (PMN) modulate their functions and play a role in the development of pathogenesis of some disease. Platelets secret various kinds of factors that affect PMN functions. They seemed to have important role in vivo, but little has been elucidated on exact mechanism of action and physiological meaning of each factor in relation to PMN functions. We studied the effects of platelets and released substances from activated platelets on the functions of PMN. Results were as follows. 1) Platelets enhanced bactericidal activities of PMN against E.coli. 2) Platelets had effects on the generation of superoxide anion (O2-) of PMN. Their effects were quite different according to the assay condition of PMN, that is, platelets inhibited O2- generation when PMN were at rest or stimulated slightly and they enhanced O2-generation of PMN that were stimulated with optimal condition. 3) Thrombin-activated platelets and their supernatant elicited a transient elevation of [Ca2] of PMN. The activity of the supernatant decreased by treating with hexokinase that decomposed ATP. Further treatment with trypsin abolished its activity almost completely. Considering with our additional experiments, factors that induced [Ca2+] elevation of PMN were ATP, beta-thromboglobulin and some trypsin-sensitive factor(s). 4) Supernatant of thrombin-activated platelets decreased random migration and chemokinesis of PMN.
College of Medical Technology, Kyoto University.
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Sasada
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Asagoe
D000255:Adenosine Triphosphate / Q000502:physiology; D001792:Blood Platelets / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D002450:Cell Communication; D002478:Cells, Cultured; D006801:Humans; D009504:Neutrophils / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013917:Thrombin / Q000494:pharmacology; D001620:beta-Thromboglobulin / Q000502:physiology
D017382:Reactive Oxygen Species; D001620:beta-Thromboglobulin; D000255:Adenosine Triphosphate; D013917:Thrombin; D002118:Calcium