Bird flu vaccine developed -- Newsday.com

Researchers have produced a bird flu vaccine made from a genetically engineered human cold virus and shown that it protected 100 percent of vaccinated mice and chickens.

While a conventional flu vaccine requires months of work and large numbers of fertilized chicken eggs, the researchers said they prepared their vaccine in only 36 days, growing it in a laboratory dish.

That could give public health officials a powerful new tool to combat the H5N1 bird flu virus if it should mutate and begin infecting humans widely.

The team is working with the Food and Drug Administration to begin human tests of the vaccine, said Dr. Andrea Gambotto of the University of Pittsburgh Medical Center, who led the team. He said the vaccine should be equally effective in humans because it is based on a human virus. The research is to be published in the Feb. 15 issue of the Journal of Virology and was made available early online.

The Pittsburgh team worked with a human cold virus, called an adenovirus, stripped of the genes required for it to cause a respiratory infection. Using genetic data from the Centers for Disease Control and Prevention, they constructed the gene for a bird flu protein called hemagglutinin and added it to the adenovirus. The hemagglutinin protein allows the bird flu virus to bind to and enter cells that it infects.

Mice and chickens injected with the vaccine were 100 percent protected against the bird flu virus, the team reported.

The team found that the vaccine produced two types of immunity - antibodies that block the hemagglutinin and prevent it from binding to cells, and T-cells that attack the virus.

"This means that this recombinant vaccine can stimulate several lines of defense against the H5N1 virus, giving it greater therapeutic value," said microbiologist Simon Barratt-Boyes of the University of Pittsburgh Graduate School of Public Health and a member of the team. "More importantly, it suggests that even if H5N1 mutates, the vaccine is still likely to be effective against it."

So far, the bird flu virus has infected mostly birds, although 152 humans have contracted it and more than 80 have died, according to the World Health Organization. Experts fear, however, the virus will mutate slightly, allowing it to infect humans more easily, leading to a pandemic. The virus originated in southeast Asia but has spread to other areas, including Turkey, Siberia and Kazakhstan.

Dr. Richard Webby, a virologist in the Department of Infectious Diseases at St. Jude Children's Research Hospital in Memphis who was not involved in the research, called the study "very promising" but said human clinical trials would be necessary. "It's a very nice study. It's the sort of thing we need to deal effectively with - a number of different approaches."

Staff writer Bryn Nelson contributed to this story.

Health/Science