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Induction of Tumor Necrosis Factor and Macrophage‐Mediated Cytotoxicity by Horseradish Peroxidase and Other Glycosylated Proteins: The Role of Enzymatic Activity and LPS
Author(s) -
Lefkowitz Doris L.,
Mills Kevin,
Castro Aaron,
Lefkowitz Stanley S.
Publication year - 1991
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.50.6.615
Subject(s) - horseradish peroxidase , tumor necrosis factor alpha , cytotoxicity , biology , secretion , receptor , lipopolysaccharide , macrophage , mannose receptor , biochemistry , polymyxin b , microbiology and biotechnology , enzyme , mannose , immunology , in vitro , antibiotics
Recent studies by these investigators have shown that horseradish peroxidase (HRP) can cause murine thioglycollate‐induced peritoneal macrophages (Mø) to produce both tumor necrosis factor (TNF) and enhance macrophage‐mediated cytotoxicity (MMC) to 3T12 target cells. The present study identifies the roles of both enzymatic activity and contaminating lipopolysacharides (LPS) (≤1 ng) on these activities. The addition of 100 ng/ml of polymyxin B (PB) to enzymatically active HRP significantly reduced TNF production but did not affect MMC. Enzymatically inactive HRP (DHRP) was more effective than HRP in both TNF production and MMC but was not affected by PB. The inability of PB to modify DHRP‐induced TNF suggests that LPS was not required. The induction of TNF and MMC in the absence of LPS was also corroborated by similar studies using Mø from endotoxin‐resistant C3H/HeJ mice. Glycosylated proteins such as HRP, DHRP, and mannosylated bovine serum albumin (M‐BSA) are known to bind to mannose receptors (mannosyl‐fucosyl receptor [MFR]) on the surface of Mø. In the present studies, M‐BSA behaved similarly to DHRP in that it induced both TNF secretion and MMC. These results suggest that binding to the MFR may be sufficient to induce TNF secretion and MMC. In addition, the data suggest that neither enzymatic activity nor LPS was required for DHRP‐induced TNF.