Study first to show that RNA interference can facilitate vaccine d...( Athens Ga. - Pharmaceutical companie...),Health

Athens, Ga. - Pharmaceutical companies and universities are racing to develop drugs that use the gene silencing mechanism known as RNA interference to treat a host of diseases. Now, a new study opens up an entirely new possibility for this powerful tool: Researchers at the University of Georgia have demonstrated for the first time that RNA interference can be used as a tool in the development of vaccines.

"Our data suggest that, at least in an animal model system, an RNAi prophylactic treatment can reduce infection and disease pathogenesis while also acting like a vaccine to engender immunity that protects against subsequent re-infection," said Ralph Tripp, Georgia Research Alliance Eminent Scholar in Vaccine Development at the UGA College of Veterinary Medicine.

Tripp, whose results appear in the December issue of the Journal of Virology, co-authored the study with doctoral student Wenliang Zhang. Previous studies by Tripp and other researchers have shown that treating mice with a small interfering RNA (siRNA) drug can reduce the replication of respiratory syncytial virus and reduce the duration of illness. RSV is a common virus that causes flu-like symptoms in otherwise healthy adults but can be fatal in infants, the elderly and people with compromised immune systems. Work from the Tripp lab has already contributed to the testing of an RNAi therapeutic for RSV infection known as ALN-RSV01, which is undergoing phase II clinical trials initiated by Cambridge, Mass.-based Alnylam Pharmaceuticals, Inc. In the latest study, Tripp explored how a related drug impacts the body's ability to respond to later infection.

The researchers treated mice with the siRNA drug, and, for control groups, treated mice with a non-specific siRNA or saline. In prophylactic treatments in which the mice were given the drug 12 hours before RSV infection, the siRNA drug reduced the viral load by up to 80 percent compared to both controls. The drug also p
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