PTX3 and infection: Locally induced at sites of infection, PTX3 opsonizes cognate microorganisms upon engagement of selected PAMPs [e.g., outer membrane protein A, OmpA, of K. pneumoniae (47), outer membrane vesicles, OMV, and meningococcal antigens of N. meningitidis (48), nucleocapsid protein of SARS_COV_2 (41)] and promotes viral neutralization as well as fungal and bacterial phagocytosis and killing (by professional phagocytes, mostly neutrophils).