Activated neutrophils secrete stored alpha 1-antitrypsin. Academic Article uri icon

Overview

MeSH

  • Cytochalasin B
  • Flow Cytometry
  • Fluorescent Antibody Technique
  • Humans
  • Leukocyte Elastase
  • Monocytes
  • N-Formylmethionine Leucyl-Phenylalanine

MeSH Major

  • Neutrophil Activation
  • Neutrophils
  • alpha 1-Antitrypsin

abstract

  • Neutrophil elastase (NE), a potent serine protease, is stored in primary granules of neutrophils and released following neutrophil activation. Alpha-1-antitrypsin (alpha 1-AT), the major inhibitor of NE, is synthesized by mature neutrophils. In the context of the maintenance of tissue homeostasis, we hypothesized that neutrophils may be able to store alpha 1-AT, thus having it available for release concordantly with NE. Immunofluorescence and quantitative flow-cytometric studies of neutrophils and monocytes labeled with fluorescein-conjugated alpha 1-AT-antibody demonstrated larger amounts of cytoplasmic alpha 1-AT in neutrophils than in monocytes. [35S]methionine-labeling and anti-alpha 1-AT immunoprecipitation analysis showed that although both neutrophils and monocytes synthesize alpha 1-AT, the proportion of newly synthesized intracellular alpha 1-AT was much higher in neutrophils than in monocytes. Flow-cytometric analysis showed that in the presence of surface stimulation with cytochalasin B followed by formyl-methionyleucylphenylalanine (fMLP), mean intracellular alpha 1-AT was decreased in stimulated neutrophils compared with that in resting cells, suggesting that the stored alpha 1-AT was rapidly released following surface triggering. Evaluation of surface-stimulated neutrophils by [35S]methionine labeling and anti-alpha 1-AT immunoprecipitation demonstrated increased secretion of alpha 1-AT compared with that of resting neutrophils, with some of the secreted alpha 1-AT capable of forming complexes with NE. Thus, neutrophils respond to surface stimulation not only by secreting NE but also by secreting its inhibitor, alpha 1-AT, suggesting that these cells have an inherent mechanism for damping the local effects of NE, their most powerful proteolytic enzyme.

publication date

  • December 1996

has subject area

  • Cytochalasin B
  • Flow Cytometry
  • Fluorescent Antibody Technique
  • Humans
  • Leukocyte Elastase
  • Monocytes
  • N-Formylmethionine Leucyl-Phenylalanine
  • Neutrophil Activation
  • Neutrophils
  • alpha 1-Antitrypsin

Research

keywords

  • Journal Article

Identity

Language

  • eng

Digital Object Identifier (DOI)

  • 10.1164/ajrccm.154.6.8970377

PubMed ID

  • 8970377

Additional Document Info

start page

  • 1829

end page

  • 1833

volume

  • 154

number

  • 6 Pt 1