Function of C-reactive protein

C-reactive protein (CRP) is an ancient highly conserved molecule and a memb er of the pentraxin family of proteins. CRP is secreted by the liver in res ponse to a variety of inflammatory cytokines. Levels of CRP increase very r apidly in response to trauma, inflammation, and infection and decrease just as rapidly with the resolution of the condition. Thus, the measurement of CRP is widely used to monitor various inflammatory states. CRP binds to dam aged tissue, to nuclear antigens and to certain pathogenic organisms in a c alcium-dependent manner. The function of CRP is felt to be related to its r ole in the innate immune system. Similar to immunoglobulin (Ig)G, it activa tes complement, binds to Fc rcceptors and acts as an opsonin for various pa thogens. Interaction of CRP with Fc receptors leads to the generation of pr oinflammatory cytokines that enhance the inflammatory response. Unlike IgG, which specifically recognizes distinct antigenic epitopes, CRP recognizes altered self and foreign molecules based on pattern recognition. Thus, CRP is though to act as a surveillance molecule for altered self and certain pa thogens. This recognition provides early defense and leads to a proinflamma tory signal and activation of the humoural, adaptive immune system.