SIRPα, or Signal Regulatory Protein Alpha, is an immunoglobulin superfamily member primarily expressed on myeloid cells, including macrophages and dendritic cells. It plays a critical role in immune regulation by interacting with its ligand, CD47, also known as the "don't eat me" signal. When CD47 binds to SIRPα, it transmits an inhibitory signal that prevents the phagocytosis of cells, thereby contributing to the immune evasion of cancer cells.
