An acute-phase protein (see acute-phase response) secreted into blood plasma by the liver in response to inflammation and infection. It comprises five identical subunits and binds to the phosphocholine component of lipopolysaccharides in the cell walls of certain bacteria and fungi. Binding of CRP increases susceptibility of the target cell to ingestion by phagocytes and can also activate the complement cascade, hence triggering destruction of pathogens by this means. Concentrations of CRP in blood are determined to assess the presence of inflammation, and elevated levels have been linked to increased risk of coronary heart disease. It was originally so named because of its ability to form a precipitate with the C polysaccharide of pneumococcus.