Penn animal study identifies new DNA weapon against...( PHILADELPHIA - Researchers at the Un...),Health

PHILADELPHIA - Researchers at the University of Pennsylvania School of Medicine have identified a potential new way to vaccinate against avian flu. By delivering vaccine via DNA constructed to build antigens against flu, along with a minute electric pulse, researchers have immunized experimental animals against various strains of the virus. This approach could allow for the build up of vaccine reserves that could be easily and effectively dispensed in case of an epidemic. This study was published last week in PLoS ONE.

"This is the first study to show that a single DNA vaccine can induce protection against strains of pandemic flu in many animal models, including primates," says David B. Weiner, Ph.D., Professor of Pathology and Laboratory Medicine. "With this type of vaccine, we can generate a single construct of a pandemic flu vaccine that will give much broader protection."

Traditional vaccines expose a formulation of a specific strain of flu to the body so it can create immune responses against that specific strain. Conversely, a DNA vaccine becomes part of the cell, giving it the blueprint it needs to build antigens that can induce responses that target diverse strains of pandemic flu.

Avian flu is tricky. Not only is it deadly, but it mutates quickly, generating different strains that escape an immune response targeted against one single strain. Preparing effective vaccines for pandemic flu in advance with either live or killed viruses, which protect against only one or few cross-strains, is therefore very difficult. How to predict which strain of avian flu may appear at any time is difficult. "We are always behind in creating a vaccine that can effectively protect against that specific strain," notes Weiner.

Instead of injecting a live or killed virus, Penn researchers injected three different species of animal models with synthetic DNA vaccines that are not taken from the flu microbe, but trick the immune sy
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