Cytokine regulation of GM-CSF and G-CSF secretion by human umbilical cord vein endothelial cells (HUVEC).
The cytokine regulation of granulocyte-macrophage colony-stimulating factor (GM-CSF) and G-CSF secretion by human umbilical cord vein endothelial cells (HUVEC) using quantitative immunoassays was studied. Unstimulated HUVEC produced no CSF. Interleukin 1 (IL-1), TNF and lipopolysaccharides (LPS) had stimulatory effects, with IL-1 being the most potent. GM-CSF and G-CSF secretion followed the same pattern, except that more GM-CSF was secreted. Exposure to stimuli for 30 min induced secretion, and detectable amounts in supernatants were found after 4 h incubation. CSF secretion was strictly regulated by the presence of a stimulus in a concentration dependent manner, and there were no signs of any endogenous downregulatory mechanism. No other cytokine tested had any stimulatory effect of its own. However, addition of IL-3 to stimulated HUVEC enhanced both GM-CSF and G-CSF secretion in a dose-dependent manner. In addition, TNF, and to a lesser degree LPS, enhanced IL-1-induced secretion. The only cytokine with a prominent downregulatory effect was IFN-gamma. IL-4 and IL-10, which downregulate CSF secretion by monocytes, had only minor effects.