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Title: Endotoxin triggers tumor necrosis factor (TNF)-dependent cytotoxicity from interferon-. gamma. (IFN-. gamma. ) primed and unprimed human monocytes

Journal Article · · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
OSTI ID:7135022

Under endotoxin-free conditions, the authors have found that human peripheral blood mononuclear cells (PBM) lack spontaneous monocyte-mediated cytotoxicity against actinomycin D-treated WEHI 164 target cells in a 6 hr /sup 51/Cr release assay. However, small amounts of endotoxin (e.g., LPS) rapidly induce monocyte-mediated cytotoxicity. IFN-..gamma.. alone is incapable of inducing monocyte cytotoxicity. Instead, pretreatment of PBM with IFN-..gamma.. for 36 hr or more primes them for triggering by amounts of endotoxin that are almost 100-fold less than that required for unprimed cells. These conditions are analogous to the two step activation sequence described for mice where IFN-..gamma.. primes and LPS triggers macrophage cytotoxic capacity. Additionally, the authors have observed that neutralizing anti-TNF monoclonal antibody abolishes the cytotoxicity measured here; and rTNF is directly cytotoxic to the target cells used in this assay. Thus, TNF is both necessary and sufficient for the monocyte mediated cytotoxicity. Since IFN-..gamma.. is thought to be produced during a variety of immunological reactions, these findings may help to explain the augmented capacity of immunologically stimulated animals for LPS-triggered TNF production and their enhanced sensitivity to the lethal effects of endotoxin.

Research Organization:
Research Institute of Scripps Clinic, La Jolla, CA
OSTI ID:
7135022
Report Number(s):
CONF-8604222-; TRN: 87-005751
Journal Information:
Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:4; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
Country of Publication:
United States
Language:
English