101. Down-regulation of surface receptors for TNF and IL-1 on circulating monocytes and granulocytes during human endotoxemia: effect of neutralization of endotoxin-induced TNF activity by infusion of a recombinant dimeric TNF receptor.
- Author
-
van der Poll T, Coyle SM, Kumar A, Barbosa K, Agosti JM, and Lowry SF
- Subjects
- Adult, Body Temperature Regulation, Dimerization, Down-Regulation, Humans, Lipopolysaccharides pharmacology, Male, Recombinant Proteins administration & dosage, Tumor Necrosis Factor-alpha metabolism, Endotoxemia metabolism, Granulocytes metabolism, Monocytes metabolism, Receptors, Interleukin-1 metabolism, Receptors, Tumor Necrosis Factor metabolism, Tumor Necrosis Factor-alpha antagonists & inhibitors
- Abstract
Leukocytes rapidly lose their surface receptors for TNF and IL-1 upon exposure to various stimuli in vitro. We sought to determine by FACS analysis changes in the expression of TNF receptors (TNFR) and type II IL-1R on circulating monocytes and granulocytes during endotoxemia in vivo, and the role of endogenous TNF in these changes. Twelve healthy subjects received an i.v. injection with LPS (2 ng/kg), directly preceded by a 30-min infusion of either a recombinant human dimeric TNFR type II-IgG fusion protein (TNFR:Fc; 6 mg/m2; n = 6) or vehicle (n = 6). LPS administration was associated with decreases in the expression of types I and II TNFR and type II IL-1R on both monocytes and granulocytes. Treatment with TNFR:Fc completely neutralized LPS-induced TNF activity (p < 0.0001 vs LPS only), modestly blunted the decrease in monocyte TNFR (p < 0.05), but did not influence reduced expression of granulocyte TNFR or monocyte/granulocyte type II IL-1R. In separate experiments, rTNF added to whole blood reduced cellular type I and type II TNFR expression by an effect on the type I TNFR; TNF did not (monocytes) decrease or only marginally (granulocytes) decreased type II IL-1R expression. LPS induces down-modulation of monocyte and granulocyte receptors for TNF and IL-1 in humans in vivo. TNF is involved in reduced monocyte TNFR expression during endotoxemia.
- Published
- 1997