Universal Flu Drug Stops All Flu Types
'Antibody Cocktail' Would Protect Against Pandemic or Seasonal Flu
"If a pandemic flu variant arose in, say, Asia next week, many or most of these procedures could be greatly expedited. That would be my hunch," Liddington said.
In mouse studies using a deadly strain of the H5N1 bird flu, mice were protected even when given the antibodies three days after infection with an otherwise lethal dose of the virus. The finding suggests that the treatment could be used to snuff out the early stages of a flu pandemic by quarantining and treating everyone in the area of an outbreak.
Universal Flu Vaccine?
At the core of the breakthrough was the finding that the vulnerable part of the flu virus is not the part attacked by current flu vaccines.
Flu viruses attack by using a surface molecule -- hemagglutinin or HA -- to enter cells. HA is shaped like a lollipop, and antibodies raised by flu vaccines attack the large round head of the lollipop. But this region is extremely variable, making it easy for flu viruses to escape vaccines.
"The lollipop head tends to dominate the immune response during a vaccine response, while the stalk is somewhat hidden," Marasco said. "But this big, globular candy top is just a decoy."
The new antibodies attack what is now shown to be a much more vulnerable part of the flu virus: the lollipop-stick stem of the HA antigen.
So why not just use this antigen to make a flu vaccine? That might very well be possible.
"These antibodies pave the way for the generation of a different kind of universal flu vaccine," Ruben Donis, PhD, chief of the CDC's molecular virology and vaccines branch, said at the news conference.
But separating the stick from the lollipop is a lot harder than it sounds. The antigen has to be exactly the right shape, and the true three-dimensional shape of the HA antigen is more like three lollipops stuck together in just the right way.
Donis says a candidate vaccine based on the new antibodies is at least three to five years away.
And a vaccine may not be better than a treatment.