C-reactive protein (also known as CRP and Pentraxin 1 (PTX1)), is a member of pentraxin protein family. Similar to other pentraxins, CRP is a pattern recognition molecule that is able to recognize pathogens and promote their clearance. CRP tends to form a non-covalently linked pentamer with each subunit made up of two antiparallel β-sheets and a single short α-helix. It is characterized by the presence of a cleft that extends from the center of the subunit to its edge at the central pore of the pentamer structure. It has been demonstrated that CRP binds to the phosphocholine moieties expressed on the surface of dead or dying cells and some bacteria. This leads to the activation of the complement system and promotion of phagocytosis by macrophages to clear necrotic and apoptotic cells. CRP is secreted by hepatocytes and is a biomarker for inflammation. IL-6 has been shown to be an effective inducer of this protein. Besides binding to apoptotic cells, CRP also binds to a variety of molecules including C1q, bacterial polysaccharide, CD64, CD32, APCS, HDL, and fibronectin. In addition to participating in immune responses, CRP is also a prominent partaker in endothelial dysfunction and atherosclerosis. It was shown that CRP may exhibit direct proantherogenic effects by upregulating angiotensin type I receptor in smooth muscle cells and promoting their migration, proliferation, neointimal formation, and reactive oxygen species production. Mature human CRP shares 71% amino acid sequence homology with its mouse counterpart.