C-reactive protein functions as a negative regulator of macrophage activation induced by apoptotic DNA.

Institute for Immunobiology and Department of Immunology, Shanghai Medical College, Fudan University, Shanghai 200032, China.
Protein & Cell (Impact Factor: 3.22). 08/2011; 2(8):672-9. DOI: 10.1007/s13238-011-1084-4
Source: PubMed

ABSTRACT C-reactive protein (CRP), an acute-phase protein with an ability to bind to nuclear antigen, has been reported to regulate cytokine secretion and modulate immune responses. We previously reported that activated syngeneic lymphocyte-derived apoptotic DNA (apopDNA) could induce macrophage activation and contribute to the initiation and progression of lupus nephritis. It is reasonable to hypothesize that CRP might regulate apopDNA-induced macrophage activation. Herein, CRP was shown to promote macrophage-mediated apopDNA uptake by binding to apopDNA (CRP/apopDNA complex). Notably, CRP/apopDNA treatment inhibited the production of inflammatory cytokines and chemokines by macrophages which could be induced by apopDNA alone. Further coculture and transwell studies revealed that CRP/apopDNA-induced macrophages prohibited apopDNA-induced macrophage activation in an IL-10 dependent manner. These results provide insight into the potential mechanism of CRP regulatory activity in macrophage activation induced by apopDNA in the context of lupus nephritis and other autoimmune diseases.