Pentraxin-related protein PTX3 also known as TNF-inducible gene 14 protein (TSG-14) is a protein that in humans is encoded by the PTX3 gene.Pentraxin 3 (ptx3) is a member of the pentraxin superfamily. This super family characterized by cyclic multimeric structure. PTX3 is rapidly produced and released by several cell types, in particular by mononuclear phagocytes, dendritic cells (DCs), fibroblasts and endothelial cells in response to primary inflammatory signals [e.g., toll-like receptor (TLR) engagement, TNF?, IL-1?]. PTX3 binds with high affinity to the complement component C1q, the extracellular matrix component TNF? induced protein 6 (TNFAIP6; also called TNF-stimulated gene 6, TSG-6) and selected microorganisms, including Aspergillus fumigatus and Pseudomonas aeruginosa PTX3 activates the classical pathway of complement activation and facilitates pathogen recognition by macrophages and DCs.