Application Methods: Western Blotting
Background: C-reactive protein (CRP) is a pentraxin family protein involved in several host defense-related functions as a result of its ability to bind to foreign pathogens and damaged host cells (1). CRP is a cyclic, non-covalent pentameric protein and normal constituent of human sera that is produced primarily by hepatocytes (2). Secretion of CRP is induced by proinflammatory cytokines, including IL-6 and IL-1β, and significantly increases during acute phase responses to tissue injury, infection, or other inflammatory stimuli (3,4). The presence of CRP is often utilized as an inflammation marker, and monitoring CRP levels in plasma is a useful tool in assessing disease progression or treatment effectiveness. CRP is also regarded as a risk assessment factor for the development and progression of cardiovascular disease (5).CRP binds to phosphorylcholine that is present on the surface of damaged tissues and in the bacterial cell wall of certain pathogens (6). Through this calcium-dependent interaction, CRP promotes agglutination and initiates the activation of the complement cascade. This results in enhanced opsonization through CRP interaction with FcγRI and FcγRIIA, which facilitates phagocytosis (7).
Application Methods: IHC-Leica® Bond™, Immunohistochemistry (Paraffin), Western Blotting
Background: CD47 is a five-pass transmembrane protein expressed on all normal cells. It binds to the SIRPa that is expressed on myeloid cells including macrophages, and neuronal cells in the central nervous system. Binding of CD47 to SIRPα promotes phosphorylation of tyrosine residues in the immunoreceptor tyrosine-based inhibitory motifs (ITIM) within theSIRPα cytoplasmic tail, inhibiting macrophage phagocytosis towards CD47-expressing cells. In this way, CD47 serves as "don't eat me" signal or a marker of "self", functioning as an innate immune checkpoint. Additionally, CD47 was reported to modulate lymphocyte cell activation and proliferation (1-3). CD47 is over-expressed in many types of cancer. The expression level of CD47 on cancer cells is negatively associated with the response to therapies, and low expression on tumor cells is associated with a better prognosis and survival. Reagents that can block CD47-SIRPα interaction are being actively pursued for therapeutic applications (4,5). In addition to SIRPα, other proteins have been reported to bind to CD47. Thrombospondin 1 (TSP1) competes with SIRPα to bind to CD47 in the extracellular region and activates signaling pathways downstream CD47 (6). CD47 can laterally associate with VEGFR2, FAS, and certain integrins in different contexts, and influences their downstream signaling (7-9). CD47 can be shed from the cell surface by proteolytic cleavage. In addition, CD47 is present on extracellular vesicles including exosomes, suggesting additional extracellular signaling potential (10).