Figure 3: Model for radiosensitization of tumors by CD47 blockade. Radiation of tumors induces expression or surface exposure of damage-associated molecular patterns (DAMP) that can lead to phagocytic clearance by macrophages of killing by cytotoxic cells. High expression of CD47 on tumor cells limits this clearance. Suppression of CD47 by morpholino treatment removes this “don’t eat me” signal and allows destruction of irradiated tumor cells by macrophages or NK cells.