生长因子和细胞因子

TNF-α is a pleiotropic pro-inflammatory cytokine secreted by various cells, including adipocytes, activated monocytes, macrophages, B cells, T cells and fibroblasts. It belongs to the TNF family of ligands, and signals through two receptors, TNFR1 and TNFR2. TNF-α is cytotoxic to a wide variety of tumor cells, and is an essential factor in mediating the immune response against bacterial infections. TNF-α also plays a role in the induction of septic shock, autoimmune diseases, rheumatoid arthritis, inflammation, and diabetes. Human and murine TNF-α demonstrate significant cross-species reactivity. TNF-α exists in two forms; a type II transmembrane protein, and a mature soluble protein. The TNF-α transmembrane protein is proteolytically cleaved to yield a soluble, biologically active, 17 kDa TNF-α, which forms a non-covalently linked homotrimer in solution. Recombinant Rat TNF-α is a soluble 157 amino acid protein (17.3 kDa) which corresponds to C-terminal extracellular domain of the full length transmembrane protein.