Temporal adaptation of human neutrophil metabolic responsiveness to the peptide formylmethionyl-leucyl phenylalanine: a comparison between human neutrophils and granule-depleted neutrophil cytoplasts.
When polymorphonuclear leukocytes (neutrophils) and soluble or particulate matter interact, the cells produce superoxide anions (O2-) and hydrogen peroxide (H2O2). The chemotactic peptide formylmethionyl-leucyl-phenylalanine (FMLP) induced a very weak response in normal neutrophils. The cellular response was changed, however, as a result of in vitro aging of the cells, i.e. the magnitude of the response was increased following storage of the cells at 22 degrees C for up to 120 min, in the absence of any stimulus, and before the addition of the peptide. When phorbol myristate acetate was used as a stimulus, there was a pronounced production of O2- and H2O2, but no change in magnitude as a result of in vitro aging. When neutrophil cytoplasts (granule-free vesicles of cytoplasm enclosed by plasmalemma) were exposed to the peptide FMLP of PMA, the vesicles produced both O2- and H2O2. There was, however, no increase in oxidative metabolite production in cytoplasts as a result of in vitro aging when either FMLP or PMA was used as a stimulus. The results thus indicate that mere incubation at room temperature primed the cells to increase their production of oxidative metabolites as a result of spontaneous exposure of hidden receptors. The fact that no such effects were observed with cytoplasts indicates that spontaneous receptor recruitment is a granule-dependent process.
Dahlgren
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Department of Medical Microbiology, Linköping University, School of Medicine, Sweden.
D015550:Cell Degranulation; D002470:Cell Survival; D003594:Cytoplasmic Granules / Q000502:physiology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D008024:Ligands; D016177:Macrophage-1 Antigen; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010101:Oxygen Consumption; D011951:Receptors, Complement / Q000378:metabolism; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D008024:Ligands; D016177:Macrophage-1 Antigen; D011951:Receptors, Complement; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic; D013481:Superoxides; D009240:N-Formylmethionine Leucyl-Phenylalanine; D006861:Hydrogen Peroxide; D013755:Tetradecanoylphorbol Acetate