TL1ATL1A, a ligand belonging to the tumor necrosis factor (TNF) family (also called TNFSF15), is expressed predominantly by endothelial cells, but is also found on lymphocytes, plasma cells and monocytes. TL1A is upregulated by the proinflammatory cytokines TNF and IL-1. On activated T cells, TL1A functions specifically via its surface-bound receptor DR3, (a member of the death-domain containing TNF receptor family) to promote cell survival and secretion of proinflammatory cytokines (1). The decoy receptor 3 (DcR3), a soluble protein of the tumor necrosis factor receptor (TNFR) superfamily blocks the action of TL1A (2). TL1A, like TNF, can be released to circulate as a homotrimeric soluble form (3). Activation of DR3 by TL1A induces the formation of a signaling complex containing TRADD, TRAF2, and RIP and activates the NF-kappaB and the ERK, JNK, and p38 mitogen-activated protein kinase pathways (4). The TL1A/DR3 pathway may be involved in atherosclerosis via the induction of pro-inflammatory cytokines/chemokines (5) and seems to play an important role in Th1-mediated intestinal diseases, such as Crohn’s disease (6). 
TL1A, Soluble (human) Detection Set (APO-54N-024)Summary of features | For the quantitative determination of soluble human TL1A from biological fluids (serum and cell culture supernatant)
|  | Monoclonal antibodies-based sandwich ELISA
|  | Detection limit: 20 pg / ml
|  | Range: 0-2.5 ng / ml
|  | Specificity : Detects only human TL1A
|  | Format: sufficient materials to run ELISAs on 5 x 96-well plates |

Principle of the KitThis assay is a sandwich Enzyme Linked-Immuno-Sorbent Assay (ELISA) developed for the direct measurement of human TL1A (hTL1A) in biological fluids. A monoclonal antibody specific for hTL1A (COAT) is coated onto the wells of the microtiter plate. Samples and standards of hTL1A are pipetted into the wells for binding to the coated antibody. After extensive washing to remove unbound compounds, hTL1A is recognized by the addition of a biotinylated monoclonal antibody specific for hTL1A (DET). After removal of excess biotinylated antibody, streptavidine-peroxidase is added. Following a final washing, peroxidase activity is quantified using the substrate 3,3’,5,5’-tetramethylbenzidine (TMB). The intensity of the color reaction is measured at 450 nm after acidification and is directly proportional to the concentration of hTL1A in the samples. 
|  Figure: Linearity of the STD curve.
|

Literature Overview:1. Migone, T. S. et al. TL1A is a TNF-like ligand for DR3 and TR6/DcR3 and functions as a T cell costimulator. Immunity 16, 479-92 (2002).
2. Hsu, M. J. et al. Enhanced adhesion of monocytes via reverse signaling triggered by decoy receptor 3. Exp Cell Res 292, 241-51 (2004).
3. Kim, S. & Zhang, L. Identification of naturally secreted soluble form of TL1A, a TNF-like cytokine. J Immunol Methods 298, 1-8 (2005).
4. Wen, L., Zhuang, L., Luo, X. & Wei, P. TL1A-induced NF-kappaB activation and c-IAP2 production prevent DR3-mediated apoptosis in TF-1 cells. J Biol Chem 278, 39251-8 (2003).
5. Kang, Y. J. et al. Involvement of TL1A and DR3 in induction of pro-inflammatory cytokines and matrix metalloproteinase-9 in atherogenesis. Cytokine 29, 229-35 (2005).
6. Bamias, G. et al. Expression, localization, and functional activity of TL1A, a novel Th1-polarizing cytokine in inflammatory bowel disease. J Immunol 171, 4868-74 (2003).
|