IL-1 and TNF-.ALPHA.-mediated regulation of IL-6, IL-8 and GM-CSF release from cultured nasal epithelial cells.

IL-6, IL-8 and GM-CSF regulate inflammatory cell infiltration and survival at sites of inflammation. IL-1, TNF-alpha, IL-6, IL-8 and GM-CSF have been reported to be released from cultured nasal epithelial cells (CNEC). Here, focusing on IL-1 and TNF-alpha as key cytokines, we examined whether these two cytokines could regulate the release of IL-6, IL-8 and GM-CSF from CNEC. CNEC were treated with antibodies to IL-1 alpha and TNF-alpha at various doses for a period of 48 hrs. The levels of IL-6, IL-8 and GM-CSF in the culture supernatants were then estimated by ELISA. Treatment of CNEC with antibodies to IL-1 alpha and TNF-alpha inhibited the release of IL-6, IL-8 and GM-CSF from them in a dose-dependent manner. The inhibition of IL-6 and GM-CSF release was significantly greater after treatment of the CNEC with the antibodies to IL-1 alpha. Furthermore CNEC expressed IL-1 receptors and TNF receptors. These results suggest that the epithelial cell-derived IL-1 alpha and TNF-alpha can regulate the release of other cytokines like IL-6, IL-8 and GM-CSF in an autocrine manner.