Anti-Pentraxin 3/TSG-14

Pentraxin 3 (PTX3),TSG-14,was initially identified as a TNF-alpha or Il-1 beta inducible gene. It belongs to the pentraxin family,which was named originally for the homo-pentameric structure formed by its members. The pentraxin family is divided into two subfamilies: the "short" and the "long" pentraxins with approximate molecular weights of 25 kDa and 50 kDa,respectively. TSG-14 is a member of the long pentraxin subfamily,which also includes the Xenopus laevis Xl-PXN1,the guinea pig apexin/p50,the rat neuronal pentraxin I (NPI) and NPR,the human neuronal pentraxin II (NPTX2) and the human neuronal activity-related pentraxin.Mature secreted TSG-14 contains a pentaxin-like domain at its carboxy-terminus that shares 23-28% amino acid (aa) sequence similarity to C-reactive protein (CRP) and serum amyloid P component (SAP),which belongs to the short pentraxin subfamily. However,the N-terminal sequence of TSG-14 does not share aa sequence homology with any of the "short" pentaxins. Unlike CRP and SAP,which forms pentamers only,TSG-14 forms both pentameric and higher ordered oligomers. Similarly to CRP and SAP,TSG-14 binds to the complement cascade component C1q. However,TSG-14 does not bind to phosphoethanolamine,phosphocholine,or high pyruvate agarose,which are known ligands for CRP and SAP. TSG-14 is a marker of the acute phase response and is highly expressed in advanced atherosclerotic plaques. While CRP and SAP are primarily produced in the liver,TSG-14 expression is strongly up regulated by TNF-alpha,Il-1 beta,and bacterial lPS in peripheral fibroblasts,endothelial cells,and macrophages.