AUGUSTA, Ga. Vaccines intended to help the body to fight off the flu bug may actually give the bug an edge, researchers say.
That doesn't mean vaccines are bad, it just may help explain why they aren't as good as they could be, says Dr. Andrew Mellor, director of the Immunotherapy Center at the Medical College of Georgia and Georgia Research Alliance Eminent Scholar in Molecular Immunogenetics.
His team along with viral immunology experts at the University of Georgia believe they can improve the efficacy of flu vaccines maybe even make them work for more than one flu season by taking away the bug's advantage.
It's a scenario Dr. Mellor equates to a brake and a gas pedal: when an infection or a vaccine feigning an infection gets the attention of the immune system, the body also mounts a counter-regulatory response to make sure the fighting doesn't get out of hand.
The enzyme, indoleamine 2,3 dioxygenase, or IDO, is part of that response. MCG researchers, led by Drs. Mellor and David Munn, showed in 1998 that fetuses use IDO to avoid rejection by the mother's immune system. IDO's silencing effect is hijacked by tumors and chronic infectious agents like HIV to avoid getting eliminated by the immune response. Acute infections such as the flu, which surface with a vengeance but typically are cleared by the body in a matter of days, appear to subscribe as well.
"We don't even understand the primary response to the influenza infection let alone to a live, attenuated virus used in vaccines," says Dr. Ralph Tripp, viral immunologist, director of UGA's Center for Disease Intervention and Georgia Research Alliance Chair of Animal Health Vaccine Development. "I think if we can understand how IDO regulates the response to viral infections, we can likely build better vaccines."
To better understand both, the researchers are using a flu-infected mouse to identify the lung cells expressing IDO, the signals prom
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| Contact: Toni Baker tbaker@mcg.edu 706-721-4421 Medical College of Georgia Source:Eurekalert |