New approaches to protecting transplanted organs make first steps towar...( AUGUSTA Ga. - Methods used by the bo...),Health

AUGUSTA, Ga. - Methods used by the body to selectively suppress the immune response may help make organ transplants safer and more effective, according to scientists.

"If you like, what we are trying to do is make every tissue transplant much more like a fetus," said Dr. Andrew L. Mellor, director of the Medical College of Georgia Immunotherapy Center and Georgia Research Alliance Eminent Scholar in Molecular Immunogenetics.

He's referencing how the genetically different fetus, which should be attacked by the mother's immune system, escapes by using powerful immune suppressors such as the enzyme indoleomine 2,3-dioxygenase. The lungs, liver, gut and eyes are examples of other human tissues that make use of this type of selective immune suppression to deal with routine contact with foreign, albeit usually harmless substances.

A new $1 million, three-year grant from Atlanta-based Carlos and Marguerite Mason Trust, administered by Wachovia Nonprofit and Philanthropic Services, will fund pre-clinical research exploring the most effective method for increasing IDO levels to improve transplant survival. The grant also will help explore the role of HLA-G dimer, another powerful immune modulator, in transplant survival and look for biomarkers that would give physicians a heads up that a rejection episode is mounting.

Using the model of a mouse with a skin graft, Dr. Phillip Chandler, a transplant biologist in Dr. Mellor's lab, will use IDO stimulators before, during and after a transplant. They'll also use IDO inhibitors to further define IDO's role in graft survival. "That is how we will learn if IDO can be induced and if that expression protects transplants," Dr. Mellor said. "This is proof of concept we are talking about which gets us toward the clinic."

Current immunosuppressive therapies for transplant patients cause a generalized suppression of the immune response that puts them at increased risk for cancers and infe
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