Tumor necrosis factor (TNF, cachexin or cachectin and formerly known as tumor necrosis factor-α) is a cytokine involved in systemic inflammation and is a member of a group of cytokines that stimulate the acute phase reaction. MultimericTNF-α™ is a high activity construct in which two trimeric TNF-α ligands are artificially linked via the collagen domain of ACRP30. The receptor TNF-R1 is activated by both the membrane-bound and soluble trimeric forms of TNF-α, whereas the receptor TNF-R2 only responds to the membrane-bound form of TNF-α (TNF-α (mouse) (multimeric) (rec.) (Prod. No. AG-40B-0021). Since the MultimericTNF-α™ mimics the membrane-bound form (forms oligomers higher than trimer), it is the only TNF-α protein that can activate the TNF-R2. For TNF-R1 activation, either "normal" TNF-α or MultimericTNF-α™ can be used.