The classical pentraxins, serum amyloid P component (SAP) and C-reactive protein (CRP), are major acute phase reactants in mouse and man. It is shown that pentraxins recognize various FcγRs and SAP opsonization activates FcγR-mediated phagocytosis and cytokine secretion. The receptor binding sites for SAP and IgG overlap, resulting in competition of IgG binding to FcγR as well as inhibition of immune complex-mediated phagocytosis by soluble pentraxins.
- Jinghua Lu
- Lorraine L. Marnell
- Peter D. Sun