首页 | 本学科首页   官方微博 | 高级检索  
   检索      


Studies on molecular regulation of phagocytosis in neutrophils. Con A-mediated ingestion and associated respiratory burst independent of phosphoinositide turnover, rise in [Ca2+]i, and arachidonic acid release
Authors:F Rossi  V Della Bianca  M Grzeskowiak  F Bazzoni
Institution:Istituto di Patologia Generale, Università di Verona, Italy.
Abstract:The role of the activation of phosphoinositide turnover and of the increase in cytosolic free calcium, Ca2+]i, in the phagocytosis and associated activation of the respiratory burst was investigated. We report the results obtained on the phagocytosis of yeast cells mediated by Con A in normal and in Ca2+-depleted human neutrophils. In normal neutrophils the phagocytosis was associated with a respiratory burst, a stimulation in the formation of 3H] inositol phosphates and 32P]phosphatidic acid, the release of 3H]arachidonic acid, and a rise in Ca2+]i. Ca2+-depleted neutrophils are able to perform the phagocytosis of yeast cells mediated by Con A and to activate the respiratory burst without stimulation of 3H]inositol phosphates and 32P]phosphatidic acid formation, 3H]arachidonic acid release, and rise in Ca2+]i. In both normal and Ca2+-depleted neutrophils the phagocytosis and the associated respiratory burst, 1) were inhibited by cytochalasin B; 2) were insensitive to H-7, an inhibitor of protein kinase C; and 3) did not involve GTP-binding protein sensitive to pertussis toxin. These findings indicate that the activation of phosphoinositide turnover, the liberation of arachidonic acid, the rise in Ca2+]i, and the activity of protein kinase C are not necessarily required for ingestion of Con A-opsonized particles and for associated activation of the NADPH oxidase, the enzyme responsible for the respiratory burst. The molecular mechanisms of these phosphoinositide and Ca2+-independent responses are discussed.
Keywords:
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号