title: Diverse effects of cytochalasin B on priming and triggering the respiratory burst activity in human neutrophils and monocytes.
abstract: Cytochalasin B, despite its potent enhancing effect on superoxide (O2-) release triggered by N-formyl-methionyl-leucyl-phenylalanine (FMLP) and many other agonists, significantly inhibited O2- release triggered by interleukin 8 (IL-8) and platelet-activating factor in human neutrophils. Cytochalasin B also enhanced changes in membrane potential stimulated by FMLP but inhibited those stimulated by IL-8. Using IL-8 as a triggering agonist, we found that the priming effect of tumor necrosis factor (TNF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) on O2- release was slightly but significantly potentiated by cytochalasin B. O2- release triggered by TNF and GM-CSF was completely abolished by cytochalasin B. In contrast to these diverse effects of cytochalasin B on O2- release, changes in cytoplasmic pH stimulated by FMLP, IL-8, TNF, and GM-CSF were not or were only minimally affected by cytochalasin B. Unlike human neutrophils, human monocytes stimulated by FMLP showed inhibition of O2- release and changes in membrane potential in response to cytochalasin B, and the priming effect of TNF and GM-CSF on O2- release in human monocytes was completely abolished by cytochalasin B. These findings indicate the diverse effects of cytochalasin B on phagocytes and suggest distinct regulatory mechanisms according to the functions, agonists, and cell types.
authors.affiliation: Department of Hematology, Research Institute, International Medical Center of Japan, Tokyo.
authors.forename: K
authors.initials: K
authors.lastname: Saeki
authors.forename: M
authors.initials: M
authors.lastname: Yagisawa
authors.forename: S
authors.initials: S
authors.lastname: Kitagawa
authors.forename: A
authors.initials: A
authors.lastname: Yuo
mesh_terms: D000328:Adult; D002630:Chemotactic Factors / Q000494:pharmacology; D003571:Cytochalasin B / Q000494:pharmacology*; D006801:Humans; D009000:Monocytes / Q000187:drug effects / Q000502:physiology; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology; D016897:Respiratory Burst / Q000187:drug effects*; D013481:Superoxides / Q000378:metabolism
chemical_list: D002630:Chemotactic Factors; D013481:Superoxides; D003571:Cytochalasin B