"Such cross-protection against bird and human influenza is considered by researchers to be the 'Holy Grail' of flu vaccines," Webby said. "By stimulating immune responses against targets not likely to mutate, the vaccine could trigger an immune defense against a broad range of variants of the virus.
"Even if the bird flu virus mutates so it becomes adapted to humans, this kind of cross protection will allow the immune system to track and attack such an emerging new variant without missing a beat," Webby said. "We wouldn't have to wait to start developing a vaccine against it until after the original virus mutated."
Webby's team showed that all mice and ferrets that received the DNA vaccine survived the challenge with the virulent H5N1 strain, while those that received a "blank" vaccine control did not survive. The vaccine also prevented weight loss in all animals challenged with the virulent virus, suggesting that the vaccine might also protect humans against serious flu-related sickness.
The studies included 16 mice or six ferrets in each vaccine or control group. The DNA vaccines targeted NP and M2--with and without the H5 avian influenza virus surface protein. All test DNA vaccines were formulated with the company's Vaxfectin