Molecule that suppresses immune response under study in type ...( AUGUSTA Ga. - The idea is to teach t...)

AUGUSTA, Ga. - The idea is to teach the immune system of children at high risk for type 1 diabetes not to attack the insulin-producing cells of the pancreas.

"We want to create a no-go zone," said Dr. Andrew Mellor, immunologist who directs the Medical College of Georgia Immunotherapy Center. Type 1 diabetes is classified as an autoimmune disease because the immune system targets healthy islet cells for destruction, leaving young patients unable to use glucose, a major fuel source for the body.

MCG researchers think they may be able to delay or even prevent that destruction by boosting the body's levels of an enzyme fetuses uses to escape the mother's immune response or by packaging islet cell antigens, which get the immune system's attention, with this suppressor. T-cells are immune cells that decide whether to attack or ignore an antigen. Dr. Mellor believes they'll ignore insulin-producing cells if they see them for the first time with indoleomine 2,3-dioxegenase, or IDO, a powerful immune system inhibitor.

"We are going to be in a situation, in the not too distant future where you can identify an individual at risk, such as a 5-year-old child who has a 90 percent chance of becoming a type 1 diabetic within 10 years," he said. "Once you know that information the onus is on medicine to do something about reducing that risk."

A three-year, $646,000 grant from the Juvenile Diabetes Research Foundation International will enable studies in a classic model of type 1 diabetes: a normal-weight mouse that develops diabetes. Eighty percent of the female mice get diabetes by age 12 to 15 weeks. MCG researchers suspect it's because they have a transient defect in their dendritic cells that hurts IDO expression. Dendritic cells, which can express IDO, show antigens to the T-cells.

A Journal of Immunology paper last year reported that when dendritic cells and IDO are depleted in the mouse, the disease gets worse. Dr. Mell
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