Interleukin, << `ihn` tuhr LOO kihn, >> is the name of a group of proteins that serve as messengers circulating among the cells of the body’s immune system. Interleukins are produced chiefly by white blood cells during the disease-fighting process known as an immune response. Individual interleukins affect only those cells that have a receptor for them. A receptor is a protein molecule on the surface of a cell. The interleukin binds to the receptor, signaling the cell to activate its immune function and to multiply. Some interleukins signal cells to deactivate. Coordination of the cells in the immune system by interleukins enables the body to neutralize viruses, bacteria, and other foreign substances.
There are more than 30 different interleukins. They are named numerically, starting with interleukin 1 (IL-1). Each has a distinct function in coordinating the immune response. For example, IL-1 from white blood cells called phagocytes helps activate other white blood cells called T cells. The T cells produce IL-2, which stimulates the production of more T cells to fight infection.
The first interleukins were discovered in the 1970’s. Current techniques in genetic engineering enable scientists to produce vast quantities of interleukins in the laboratory. Researchers are investigating many applications of interleukins, such as treatment of immune deficiency diseases and cancer, and preventing rejection of transplanted organs.
