Human Leukocyte Surface Antigen CD47 (CD47) Protein

Background

CD47, also known as integrin-associated protein (IAP), is a widely expressed transmembrane glycoprotein that plays a critical role in immune regulation, cell signaling, and cellular adhesion. It is a member of the immunoglobulin superfamily and is involved in numerous biological processes, including immune evasion, apoptosis, angiogenesis, and cell migration. One of CD47's primary functions is to act as a "don't eat me" signal to prevent macrophage-mediated phagocytosis, which is a key component in the immune system's ability to clear dead cells and pathogens. CD47 interacts with signal regulatory protein alpha (SIRPα), a receptor primarily expressed on myeloid cells, such as macrophages and dendritic cells. The binding of CD47 to SIRPα sends an inhibitory signal to macrophages, preventing the phagocytosis of CD47-expressing cells. This interaction plays a critical role in protecting normal cells from immune clearance but can also be exploited by cancer cells to evade immune detection and destruction.