These findings take the researchers closer to their goal of targeted manipulation of the immune system. "In principal we can use the new immunosuppressive drug to do that. We can treat mice with the reagent, and introduce antigens that their immune systems would normally respond vigorously to. The prediction is that the mouse treated with this reagent will no longer respond vigorously to these antigens. Our preliminary data indicates that we are on the right track."
In fact, the Perugia scientists have shown that the mouse model for type 1 diabetes has a specific defect in the IDO mechanism. "That means that if you have a defect in that mechanism, those mice and, therefore by extrapolation, human beings too, are much more likely to get type 1 diabetes." That knowledge needs to be used to help eliminate or at least reduce the risk of children identified at risk, Dr. Mellor said, referencing a large newborn screening program for type 1 diabetes under way by Dr. Jin-Xiong She, director of the MCG Center for Biotechnology and Genomic Medicine and Georgia Research Alliance Scholar in Genomic Medicine. "We have to use our immunology knowledge to protect patients at risk from getting diabetes," Dr. Mellor said.
When the immune system is not responsive enough, such as in the case of a tumor, they can block the IDO mechanism in the cells so they would regain the ability to attack. His colleague, Dr. Munn, is moving toward clinical trials on blocking this mechanism pharmacologically, much as they did in the early days to show the role of IDO in helping a fetus avoid rejection.
"It comes back to the unifying theme of what it is at the molecular and cellular level that regulates whether the immune system is going to respond or not to any given circumstance," Dr. Mellor says. "That is what we are working on and the results reported in this paper
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Contact: Toni Baker
tbaker@mail.mcg.edu
706-721-4421
Medical College of Georgia
15-Aug-2003