Tumor Necrosis Factor is secreted by macrophages, monocytes, neutrophils, T cells, natural killer cells following their stimulation by bacterial lipopolysaccharides. Cells expressing CD4 secrete TNF-alpha while CD8(+) cells secrete little or no TNF-alpha. Stimulated peripheral neutrophilic granulocytes but also unstimulated cells and also a number of transformed cell lines, astrocytes, microglial cells, smooth muscle cells, and fibroblasts also secrete TNF. Human milk also contains this factor. The synthesis of TNF-alpha is induced by many different stimuli including interferons, IL-2, GM-CSF, SP, Bradykinin, Immune complexes, inhibitors of cyclooxygenase and PAF (platelet activating factor). Human TNF-alpha is a non-glycosylated protein of 17 kDa and a length of 157 amino acids. Murine TNF-alpha is N-glycosylated. Homology with TNF-beta is approximately 30%. TNF-alpha forms dimers and trimers.
Aliases- TNFSF2, Cachectin, Differentiation-inducing factor (DIF), Necrosin, Cytotoxin
- Recombinant Human Tumor Necrosis Factor Alpha (TNF)
Formulation- Lyophilized from a 0.2 µm filtered solution in PBS (pH 7.2)
Endotoxin Level- <1.0 EU/µg of recombinant protein as determined by the LAL method.
Storage Condition- The lyophilized protein is stable for at least one year from date of receipt at -70°C. Upon reconstitution, this cytokine can be stored in working aliquots at +2° to +8°C for one month, or at -20°C for six months, with a carrier protein without detectable loss of activity. Avoid repeated freeze/thaw cycles.