Human umbilical vein endothelial cells were cultured in supernatants of peripheral blood monocytes that had been cultured for 3 days with and without lactoferrin. Colony-stimulating activity (CSA) was measured in supernatants of the endothelial cell cultures and appropriate control cultures using normal T-lymphocyte-depleted, phagocyte-depleted, low-density bone marrow cells in colony growth (CFU-GM) assays. Monocyte-conditioned medium contained a nondialyzable, heat labile factor that enhanced 4-15 fold the production of CSA by endothelial cells. The addition of lactoferrin to monocyte cultures reduced the activity of this monokine by 69%. Lactoferrin did not inhibit CSA production by monokine-stimulated endothelial cells. Therefore, the production of CSA by these cells is regulated by a stimulatory monokine, and the production and/or release of the monokinase is inhibited by lactoferrin, a neutrophil-derived putative feedback inhibitor of granulopoiesis. Inasmuch as a similar monokine is known to stimulate CSA production by fibroblasts and T lymphocytes, we suggest that mononuclear phagocytes play a pivotal role in the regulation of granulopoiesis by recruiting a variety of cell types to produce CSA.
CITATION STYLE
Bagby, G. C., McCall, E., Bergstrom, K. A., & Burger, D. (1983). A monokine regulates colony-stimulating activity production by vascular endothelial cells. Blood, 62(3), 663–668. https://doi.org/10.1182/blood.v62.3.663.663
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