CD47

CD47 is a kind of protein that is found on the surface of many cells in the body. It tells circulating immune cells called macrophages not to eat these cells. The body uses the CD47 protein to protect cells that should be protected and to help dispose of cells that are aged or diseased. For instance, red blood cells start off with a lot of CD47 on their cell surface when young but slowly lose CD47 as they age. At some point, the amount of CD47 on the surface of an aging red blood cells is not enough to stave off the macrophages, and those older cells are devoured and destroyed, making way for new red blood cells. In this way, the supply of fresh blood cells is constantly replenished.

Unfortunately, some cells that should be destroyed are not. Researchers at Stanford have discovered that nearly every kind of cancer cell has a large amount of CD47 on the cell surface. This protein signal protects the cancer against attack by the body's immune system. Stanford investigators have discovered if that they block the CD47 "don't-eat-me" signal through the use of anti-CD47 antibodies, macrophages will consume and destroy cancer cells. Deadly human cancers have been diminished or eliminated in animal models through the use of anti-CD47 antibody.

News:

Oxford University begins clinical trial of anti-CD47 antibody in the treatment of acute myeloid leukemia (Oxford University's announcement is here).

Anti-CD47 antibody may offer new route to successful cancer vaccination

Engineered molecules boost immune attack on cancer