Universal Flu Drug Stops All Flu Types
'Antibody Cocktail' Would Protect Against Pandemic or Seasonal Flu
Universal Flu Vaccine? continued...
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
"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
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.
"People tend to emphasize vaccines as the Holy Grail of flu, as it were.
But these antiviral antibodies are very effective, and can be very effective in
a pandemic setting -- they just need to be used judiciously," Liddington
said. "These antivirals are ready to go and should be effective just as
they are, as soon as they get through FDA approval and are stockpiled in large
enough amounts in metropolitan areas where an outbreak might begin."
Donis, Liddington, Marasco, and colleagues report the findings in the Feb.
22 advance online issue of the journal Nature Structural & Molecular