Soluble extracellular domains of human SIRPα and CD47 expressed in Escherichia coli enhances the phagocytosis of leukemia cells by macrophages in vitro

► We characterized the soluble extracellular domains of human SIRPα and CD47. ► These fusion proteins could promote phagocytosis of tumor cells by macrophages. ► The hSIRPext binds to tumor cells via the specific interaction with CD47.