Scientists May Have New Way to Fight the Flu

Feb. 23 -- SUNDAY, Feb. 22 (HealthDay News) -- A new scientific discovery could someday lead to medications to fight the flu as well as a vaccine that would not have to be changed every year because it could target a broad range of flu strains.

"We identified new human antibodies that inactivate influenza, not just bird flu, but any of the seasonal influenza viruses that affect us in the winter," said researcher Dr. Wayne A. Marasco, an associate professor of medicine at Harvard Medical School and the Dana-Farber Cancer Institute.

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.

"These flu antibodies can be developed into fully human antibody drugs that could be used in the clinic," Marasco said. Such drugs would be used in the same way antiviral medications, such as Tamiflu, are used today.

Antivirals generally are given to prevent a virus after exposure or to treat a virus once it develops. This year, however, the commonly circulating H1 strains of the influenza virus are resistant to Tamiflu.

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.

But the newly identified antibodies attack the stem of the virus, which is more resistant to change and "does not change amongst the various influenza viruses," he said.

"These antibodies do not replace the flu vaccine," Marasco said. "But the exciting part is, this gives us a new approach to vaccine development. This is a new area that is highly conserved, and the viruses do not appear to easily undergo change in their genetic code to escape the antibodies directed against them."