The toxic effects of endotoxin-free human recombinant tumor necrosis factor (rH-TNF), shown to contain less than 50 pg endotoxin/mg rH-TNF, were investigated and compared with those of rH-TNF and endotoxin coadministered at 4-400 ng endotoxin/mg rH-TNF in female Sprague-Dawley rats. The mean lethal dose of 5.9 mg/kg rH-TNF found for the endotoxin-free rH-TNF was far higher than that attributed to rH-TNF by other investigators. Coadministration with endotoxin derived from E. Coli. Salmonella abortus equi, or Serratia marcescens reduced the apparent mean lethal dose of rH-TNF in correspondence to the endotoxin concentration, with a value of 0.7 mg/kg rH-TNF observed at 1600 ng, 757 ng, and 5260 ng endotoxin/mg rH-TNF, respectively. Coadministration also resulted in more severe histopathologic and physicochemical effects than rH-TNF alone. Histopathologic abnormalities observed only in coadministration included interlobular edema and hemorrhage of the pancreas and, most remarkably, splenomegaly, which was not observed with rH-TNF alone even at lethal doses. The results indicate that particular care in determining endotoxin contamination is essential in any consideration of TNF toxicity.
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Int J Ophthalmol
May 2022
Eye Centre, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, Zhejiang Province, China.
Aim: To investigate the mechanism of the tight junction (TJ) disruption and the association between tumor necrosis factor (TNF)-α and matrix metalloproteinase (MMPs) under hyperosmotic condition in primary human corneal epithelial cells (HCECs).
Methods: The cultured HCECs were exposed to media which adding sodium chloride (NaCl) for hyperosmolar stress or adding rh-TNF-α (10 ng/mL). NF-κB inhibitor (5 µmol/L) or GM-6001 (potent and broad spectrum MMP inhibitor, 20 µmol/L) was added 1h before that treatment.
J Clin Cell Immunol
June 2016
Department of Reproductive Biology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106, USA.
We reported at the Keynote Forum of Immunology Summit-2015 that recombinant human (rh) TNF-α or rhIL-6 stimulated production of matrix metalloproteinase-9 (MMP-9) in the T/C28a2 and C-28/I2 human immortalized chondrocyte cell lines. Furthermore, we reported that tocilizumab (TCZ), a fully humanized monoclonal antibody which neutralizes IL-6-mediated signaling, inhibited the rhIL-6-mediated increase in the production of MMP-9. IL-6 is also a known activator of the JAK/STAT signaling pathway.
View Article and Find Full Text PDFSci Rep
March 2016
Infectious Signaling Network Research Center and Research Institute for Medical Sciences, Department of Physiology, School of Medicine, Chungnam National University, Daejeon, 301-747, Republic of KOREA.
Apurinic apyrimidinic endonuclease 1/Redox factor-1 (APE1/Ref-1) is a multifunctional protein with redox activity and is proved to be secreted from stimulated cells. The aim of this study was to evaluate the functions of extracellular APE1/Ref-1 with respect to leading anti-inflammatory signaling in TNF-α-stimulated endothelial cells in response to acetylation. Treatment of TNF-α-stimulated endothelial cells with an inhibitor of deacetylase that causes intracellular acetylation, considerably suppressed vascular cell adhesion molecule-1 (VCAM-1).
View Article and Find Full Text PDFIntegr Mol Med
August 2015
Department of Medicine, Division of Rheumatic Diseases, Department of Reproductive Biology, Case Western Reserve University School of Medicine, USA.
Two immortalized human juvenile chondrocyte cell lines, T/C28a2 and C28/I2, were employed to determine the extent to which recombinant human (rh) IL-6 or rh-TNF-α increased the production of matrix metalloproteinase-9 (MMP-9). The effect of rhIL-6 on neutrophil gelatinase-associated lipocalin (NGAL) was also assessed. Although C28/I2 chondrocytes incubated with rhIL-6 (50 ng/ml) increased MMP-9 production which could not be mimicked by the T/C28a2 chondrocyte line, the effect of rhTNF-α on MMP-9 was more robust than with rhIL-6.
View Article and Find Full Text PDFCancer
October 2011
Department of Veterinary Clinical Sciences, University of Minnesota, Veterinary Medical Center, St. Paul, Minnesota, USA.
Background: The carbohydrate sialyl Lewis X (sLeX) is expressed on leukocytes and carcinoma cells and binds to selectins during inflammatory processes and early metastasis. Synthesis of sLeX depends on activity of enzymes, including α(1,3/1,4) fucosyltransferase (FucT-III). Tumor necrosis factor-α (TNF-α) up-regulates FucT-III, resulting in increased sLeX in the airways of patients with respiratory disease; however, the mechanisms that regulate sLeX in the inflammatory tumor microenvironment are not well understood.
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