Purity > 95% by SDS - PAGE, MW: 18 kDa with a 6*His tag at the C-terminus. Tumor Necrosis Factor-α (TNF-α) is a highly pleiotropic cytokine with multiple activities other than its originally discovered role of tumor necrosis in rodents. It contributes to both inflammations during infections and anti-inflammatory/tissue repair processes after clearance of infection. TNF-α is mainly produced by activated macrophages, T lymphocytes, and natural killer (NK) cells. The activity of TNF-α is mediated through two cell surface receptors, TNF-R1 (p55) and TNF-R2 (p75) that differ in their signaling activity. TNF-α's primary role is in the regulation of immune cells. It can induce cell death of certain tumor cell lines. About 28% of cancers are susceptible to direct cell killing mediated by soluble TNF-α.