Experimental vaccine protects against many flu viruses

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http://www.sciencenews.org/view/generic/id/350606/description/Experimental_vaccine_protects_against_many_flu_viruses

A catchall flu shot is a step closer to reality. Researchers report May 22 in Nature that they have engineered a vaccine that immunizes mice and ferrets against decades’ worth of influenza viruses. They say it could protect people for several years — and from many different flu viruses — without having to be reformulated and delivered annually the way current flu vaccines are.

Researchers from the National Institutes of Health have engineered a nanoparticle vaccine that shields lab animals from several viruses that sickened people between 1934 and 2007. This vaccine won’t stop all flu viruses, but it may immunize against many versions of H1N1, a subtype of influenza A that causes many cases of seasonal flu.

To create the new vaccine, the researchers fused a protein called hemagglutinin from the flu virus to a bacterial protein called ferritin. Hemagglutinin is a spiky molecule that studs the flu’s outer coat and helps the virus grasp host cells. There are at least 17 different subtypes of hemagglutinin, numbered H1 through H17. The N in a flu strain’s name stands for neuraminidase, another variable protein on the viruses’ outer coat. Flu viruses mutate rapidly, and each year a slightly different form of the flu causes outbreaks.

For the experimental vaccine, the researchers chose hemagglutinin from an H1N1 virus that made people sick in 1999. The team married a portion of the protein to the ferritin protein from a stomach bacterium called Helicobacter pylori. The fused proteins assembled into a nanometer-scale ball with ferritin on the inside and hemagglutinin spikes on the outside.