The effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on tumor necrosis factor (TNF) production by peritoneal cells.

Recent studies in mice have demonstrated that TNF plays a critical role in mediating the TCDD-induced enhanced inflammatory response to intraperitoneal (i.p.) sheep red blood cells. The current studies were designed to evaluate the effects of TCDD on TNF production by ex-vivo peritoneal cells and a peritoneal macrophage cell line (IC-21) stimulated with LPS. In support of the hypothesis that TCDD can act directly on the peritoneal macrophage to increase TNF production, following pretreatment with TCDD, both ex-vivo peritoneal cells and IC-21 cells produced increased levels of bioactive TNF when stimulated with LPS. Flow cytometric analyses of IC-21 cells indicate that TCDD exposure increases intracellular production and secretion of TNF but does not alter levels of membrane associated TNF.