Universal Flu Vaccine in Development

by Terri Potratz | February 23, 2009 at 04:22 pm

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Scientists have inched closer to developing a universal flu vaccine after identifying human antibodies that inactivate various invluenza viruses, including bird flu. Dr. Wayne A. Mrasco of Harvard Medical School and the Dana-Farber Cancer Institute was the leading researcher among a team of 20, and has been working on this project for over 2 years.

The antibody drugs attack the "Achilles heel" of the influenza virus by targeting the stalk rather than the globular head, which has the ability to genetically mutate. This is why we need a new flu vaccine each year.

Antiviral medications can be problematic because the virus can quickly become resistant to the drugs:

Resistance develops because a drug targets the large head of the flu virus, but the virus is able to quickly mutate, making it resistant to medications and vaccines, Marasco explained. That's why there is a new seasonal flu vaccine every year, he said.

The antibodies attack the virus stem, rather than the head, a portion which is much less likely to mutate and "does not change amongst various influenza viruses," Marasco said. Antibodies will not replace antiviral treatment and prevention, but rather supplement it.

The antibodies recognize a new part of the influenza virus and inactivate the virus by a new mechanism, Marasco said, "so it's really a new target, new mechanism, new human antibodies."

Antibodies can be used as drugs, he noted, adding that drugs derived from antibodies are commonplace in treatment for such cancers as colon, breast and lymphoma.

Drugs developed from the newly identified antibodies could, in combination with other treatments, prevent or treat certain avian and seasonal flu strains and could also lead to the development of a long-lasting flu vaccine, the researchers said.

This discovery points to the possibility of a universal flu vaccine because it opens the doors to finding other antibodies that could be more effective. The antibodies in this case were effective against roughly half of known flu strains, including the N5N1 avian flu strain and the 1918 flu strain which killed 40 million people worldwide.

Human clinical trials could begin as soon as 2011.