Recombinant Mouse DR3/TNFRSF25 Fc Chimera Protein, CF

Death receptor 3 (DR3), also known as TNFRSF25, LARD, WSL-1, APO3, TRAMP, and TR3, is a 55 kDa TNF receptor superfamily protein that is predominantly expressed by lymphocytes. TNF receptor superfamily members have varying numbers of extracellular cysteine-rich domains (CRDs) with conserved cysteine spacing (1, 2). DR3 contains four CRDs and one cytoplasmic death domain (3, 4). Alternative splicing of mouse DR3 generates an isoform that lacks the fourth CRD and a secreted isoform that consisits of only the extracellular domain (ECD) (3). Human DR3 exists in at least eleven alternate splice forms (5). Within the ECD, mouse and human DR3 share 59% amino acid (aa) sequence identity. DR3 shares 20%-28% aa sequence identity with the ECD of death domain receptors DR5, DR6, EDAR, Fas, NGF R, and TNF RI. Naïve B and T cells preferentially express truncated soluble isoforms of DR3, whereas stimulated lymphocytes preferentially express transmembrane DR3 (5). TL1A/TNFSF15, a high affinity DR3 ligand which also exists in membrane bound and soluble forms, is expressed by activated endothelial cells and T cells (6, 7). TL1A additionally binds to DcR3/TNFRSF6B, a soluble decoy receptor that interferes with DR3 activation (8). DR3 signaling triggers either apoptosis or NF kappaB-induced anti-apoptotic effects depending on the cellular setting (9). Apoptosis is partially impaired during negative selection of thymocytes in DR3-null mice (10). TL1A interactions with DR3 augment T cell proliferation and proinflammatory cytokine secretion (6, 7, 11, 12). DR3 is upregulated by inflammatory stimulation of CCR9⁺ T cells, a T cell subset important in mucosal immunity (11). T cell and macrophage DR3 expression is prominent in several inflammatory disorders such as Crohn’s disease, inflammatory bowel disease, and atherosclerosis (7, 11-15). DR3 activation on IFN-gamma treated THP-1 cells induces the production of TNF-alpha, CXCL8, CCL2, MMP-1, -9, and -13 (14, 15).