New Flu Clue

Just-found protein may hint at why some strains are more potent

WEDNESDAY, Dec. 12, 2001 (HealthDayNews) -- For 20 years, researchers thought the dreaded flu virus was made up of 10 different proteins that guide its ability to duplicate itself, attack healthy cells and make you miserably sick.

But, researchers from the National Institute of Allergy and Infectious Diseases (NIAID) recently surprised themselves by finding an 11th protein in the virus.

"We found the first new flu gene in 20 years," says lead researcher Dr. Jonathan Yewdell, a NIAID viral immunologist, and he says it happened by accident.

Yewdell and his team were studying how the human immune system responded to "junk peptides" created by the flu virus. Peptides are molecular chains made up of pieces of proteins. Junk peptides are created when something goes wrong in the way the virus is replicating. The researchers were simply trying to see if the immune system recognized and responded to the junk peptides when they came across the new protein, he says.

Once they realized what they had found, they wanted to know what role this protein plays in the virus. So, with help from Mt. Sinai School of Medicine scientists, in New York City, they developed a virus that lacked the protein to see how it would behave.

"What we found was that this protein was not necessary for virus replication, but if a virus lacked this protein, the ability of the virus to kills cells was delayed," says Yewdell. The researchers speculate that this protein could be a factor in what makes some strains of flu deadlier than others.

But Yewdell cautions it's too soon to know what the protein really does. "This isn't the magic wand that will explain the flu. This is just the start of what will have to be a lot of work to find out what it does and to put it in the context of the other 10 proteins we know," he says.

Results of the study appear in the current issue of the journal, Nature Medicine.

Robert A. Lamb, professor of molecular and cellular biology at Northwestern University, in Chicago, says, "This was a clever experiment because nobody was looking for [the protein], and we had no reason to believe it even existed." He says, from a basic science perspective, this is a very important observation.

But, like Yewdell, he cautions against looking for any practical implications just yet. "Without a doubt, [this discovery] opens avenues for lots of further experiments, but it's too early to know how important it will be."

What To Do

While the scientists are figuring out how the virus works, you can read about how to prevent the flu at Health Canada or at the American Lung Association Web sites.

And, if you're wondering if the flu is coming to a neighborhood near you, check the maps at

SOURCES: Interviews with Jonathan Yewdell, M.D., Ph.D., viral immunologist, NIAID, Bethesda, Md.; Robert A. Lamb, professor, molecular and cellular biology, Northwestern University, investigator, Howard Hughes Medical Institute, Chicago, Ill.; December 2001 Nature Medicine
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