CD47, known as Integrin-Associated Protein (IAP), is a transmembrane protein encoded by the CD47 gene in the human body, belonging to the immunoglobulin superfamily. It interacts with integrins, Thrombospondin-1 (TSP-1), and Signal Regulatory Protein alpha (Sirpα). Its protein structure consists of an extracellular N-terminal IgV domain, 5 transmembrane domains, and an intracellular C-terminal transmembrane glycoprotein, widely expressed on the surface of almost all normal cells.Sirpα is a membrane glycoprotein from the SIRP family, predominantly expressed on macrophages, dendritic cells, and neural cells. As an inhibitory receptor, it interacts with CD47, releasing a “do not eat me” signal, thereby inhibiting macrophage engulfment. Some tumor cells also overexpress CD47 to escape the immune system. The cytoplasmic region of SIRPα is highly conserved between humans, rats, and mice, containing numerous tyrosine residues ITIM. When binding with CD47, Sirpα is phosphorylated and recruits SHP1 and SHP2, transmitting intracellular signals.The Accegen SIRPα Blockade Reporter Cell Line is a reporter cell line that activates CD3ζ and subsequently luciferase expression upon CD47 binding to SIRPα. This activation can be blocked by antibodies with a blocking effect, making this cell model suitable for screening blocking antibodies. Luciferase readings represent the activation of the signaling pathway and the blocking effect, thereby allowing for the evaluation of the in vitro effects of CD47 and SIRPα-related antibody drugs.
