Tumor Necrosis Factor-beta (TNFβ), also known as Lymphotoxin-alpha (LT-α), is a member of the TNF superfamily. Human TNFβ is a 22 kDa protein that shares 73%amino acid sequence identity with mouse and rat TNFβ. Secreted TNFβ can form homotrimers that bind and activate multiple receptors. With membrane-localized LT-β, LT-α /TNFβ forms heterotrimers to bind and activate the LT-β R/TNFRSF3. TNF was initially identified for inducing necrosis in experimental cancers, but then a tumour promoting role was identified. TNFβ is expressed in activated T- and B- lymphocytes and contributes to autoimmune disease. TNFβ is found to mediate lymph node development, inflammation, and immune function.