“…Additionally, PTX3 has been shown to opsonize pathogens, thus enhancing complement activation and phagocytosis during bacterial and fungal infections, aiding in pathogen clearance through recruitment of C1q and stimulation of the Fc␥ receptor, respectively (16,(18)(19)(20)(23)(24)(25)(26)(27)(28). Despite immunoprotective properties, prolonged elevation of patient PTX3 levels has been reported to correlate with increased morbidity and mortality in severe sepsis (29)(30)(31)(32)(33)(34)(35) thought to arise from increased tissue factor (TF) expression on the surface of monocytic phagocytes and vascular endothelial cells observed in vitro following LPS stimulation (36,37). Although neutrophils store PTX3 in a preformed active state within cytoplasmic granules, giving rise to short-lived spikes in serum PTX3 levels following degranulation, prolonged elevation can arise from induced expression by monocytic cells, e.g., monocytes, macrophages, dendritic cells, and endothelial cells (17,19,25,28,38,39).…”