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Dexamethasone promotes phagocytosis and bacterial killing by human monocytes/macrophages in vitro
Author(s) -
Goes Annette,
Hoekstra Karin,
Berg Timo K.,
Dijkstra Christine D.
Publication year - 2000
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.67.6.801
Subject(s) - phagocytosis , biology , in vitro , dexamethasone , microbiology and biotechnology , macrophage , immunology , monocyte , biochemistry , endocrinology
One of the actions of glucocorticoids (GC) in multiple sclerosis (MS) is an inhibitory effect on demyelination. This can be caused by a reduction in the number of infiltrating macrophages and/or by an effect on the phagocytosis of myelin. Here we investigate the effect of GC on the phagocytosis of myelin. Contrary to what was expected, we found that incubation of human monocytes with dexamethasone (DEX) for 48 h augmented (approximately threefold) the phagocytosis of myelin. This enhancement of phagocytosis by human monocytes was not restricted to myelin. Phagocytosis of various particles mediated by different macrophage receptors was increased by DEX. We found that not only the phagocytosis of Staphylococcus aureus bacteria was augmented, but also the killing of these bacteria was at least twice as effective after culture with DEX. Tumor necrosis factor α production of human monocyte‐derived macrophages induced by lipopolysaccharide and S. aureus was suppressed by DEX. Together our results show that DEX promotes the phagocytosis of particles by human monocytes and thereby may contribute to tissue repair after immune‐mediated tissue damage or infection. These data shed a new light on the clinical application of GC. J. Leukoc. Biol. 67: 801–807; 2000.