The job of cells known as iNKT cells is to regulate the immune system’s response to infections and other disorders, ensuring that only diseased tissue, not healthy tissue, is targeted for attack. Type I diabetes, an “autoimmune” disorder, occurs when the immune system mistakenly attacks healthy insulin-producing cells in the pancreas. A new study involved the body’s mechanism for activating iNKT cells. The mechanism involves a class of cells known as dendritic cells, whose role is to alert the rest of the immune system to the presence of infection or another health problem. The surface of dendritic cells is studded with proteins called CD1d, which display lipids, or fat, molecules. One such potent activating lipid is known as alpha-galactosylceramide. When iNKT cells sense the presence of these molecules, the cells are activated, reining in the immune system’s attack on normal tissue. Dana-Farber researcher Brian Wilson, who is an assistant professor at Harvard Medical School, and his colleague Michael Clare-Salzer of the University of Florida administered a-galactosylceramide to mice that were prone to developing diabetes. The drug prevented diabetes in the mice. The study was supported by the National Institutes of Health and the Juvenile Diabetes Research Foundation International.