WASHINGTON (Reuters) - Researchers said they had discovered one important way that immune system proteins known as chemokines work, and said their findings could help to find better treatments for diseases like AIDS and cancer. Dr. Tamas Oravecz of the Food and Drug Administration`s (FDA) center for Biologics Evaluation and Review, working with Mark Gorrell at the University of Sydney, said they found a protein that controls chemokines. Chemokines are signalling chemicals that are key to immune system functions. For example, they summon the right immune cells to the scene of an infection. Writing in the Journal of Experimental Medicine, Oravecz and Gorrell`s teams said they had found a protein known as CD26 on the surface of certain white blood cells can either enable or disable chemokines. They said new therapies could change the way CD26 acts on chemokines, perhaps preventing infections with HIV, which is known to use some of the same receptors, or chemical doorways, that chemokines do.