Should the Next Weapon in Bird Flu Fight be DNA?

British biochemical engineers, in a paper published in in the November and December issue of the journal Biotechnology Progress, suggest that DNA vaccines should be considered as a weapon against a potential influenza pandemic such as that feared possible should the avian influenza virus H5N1 mutate into a bug that is transferable from human to human.

"A DNA vaccine is not a panacea, however it could be useful if the situation gets out of hand," Peter Dunnill of University College London said in a statement released today by The American Chemical Society.

"If we're going to try it, we need to move,” he said. “You can't expect to walk into a production facility, hand over the instructions, and expect them to make it on the spot. It's going to take some weeks, and we really don't know how much time we have."

A DNA vaccine could be produced in as little as two or three weeks, Dunnill said.

DNA vaccines are derived from the DNA of an infectious organism. They work by being injected into the cells of a person, usually in muscle tissue. Once injected, the genes of the foreign DNA are expressed, starting a cascade that leads to the synthesis of infectious organism proteins inside the injected cells, causing the immune system to respond as if infected by the infectious organism itself.

DNA vaccines, however, are not a proverbial silver bullet and the technique is largely untested in humans.

To create a DNA vaccine, scientists would create a "loop" of DNA -- a plasmid vector -- that would contain the biological construction plans for a protein on the outer surface of the H5N1 virus. When that DNA is injected into cells, it would quickly reproduce the protein and trigger immunization in much the same way as a conventional vaccine does. [For a more technical explanation, click here to visit a website from microbiologist John C. Brown of Kansas University.]