Pentraxin 3 (PTX3) (PTX3)

Pentraxin 3 (PTX3) is a soluble pattern recognition receptor and the prototype of the long pentraxin family, playing a pivotal role in the humoral innate immune response (UniProt P26022; Garlanda et al., 2018). Unlike short pentraxins like C-reactive protein, PTX3 is produced locally at the site of infection or inflammation by macrophages, dendritic cells, and endothelial cells (Mantovani et al., 2013). The PTX3–macrophage interaction axis is central to regulating the inflammatory microenvironment, where PTX3 binds to various ligands, including C1q and Fcγ receptors, to facilitate phagocytosis and modulate complement activation (Bonavita et al., 2015). In oncology, PTX3 has been identified as an extrinsic oncosuppressor that limits complement-driven macrophage recruitment and inhibits tumor-promoting inflammation (Bonavita et al., 2015). However, its role can be context-dependent, sometimes influencing macrophage polarization toward different functional phenotypes depending on the disease state (Garlanda et al., 2018). PTX3 also serves as a significant clinical biomarker for cardiovascular diseases, sepsis, and certain viral infections like COVID-19, reflecting the intensity of the local inflammatory response (PubMed 33558737). Therapeutic interventions targeting this axis are currently being explored, including the administration of recombinant PTX3 to treat fungal infections or to harness its tumor-suppressive properties (Mantovani et al., 2013). Understanding the nuances of the PTX3–macrophage axis is essential for developing targeted immunotherapies that can precisely modulate innate immunity without causing systemic toxicity.

Other names

Pentraxin-related protein PTX3Tumor necrosis factor-inducible gene 14 proteinTSG-14Long pentraxin 3

PTX3 acts as a soluble pattern recognition receptor that binds to C1q, factor H, and Fcγ receptors to modulate complement activation and macrophage-mediated phagocytosis and polarization (Garlanda et al., 2018; Bonavita et al., 2015).