Nanoparticle vaccine shows protection against different strains of flu

A nanoparticle flu vaccine that creates protection from different strains of the virus has been demonstrated in animal trials, according to a study in Nature Medicine. Flu vaccines have to be updated each year because the virus mutates constantly, so researchers targeted the ‘stem’ of the virus’ H protein, which is less subject to mutation. They generated a vaccine using an H1N1 virus and found that it completely protected mice and partially protected ferrets infected with the H5N1 virus.

 

Dr. Walter A. Orenstein, Professor, Department of Medicine, Division of Infectious Diseases and Associate Director, Emory Vaccine Center, Emory University School of Medicine (webpage)

Expertise: Evolution, emergence, transmission and pathogenicity of influenza viruses, vaccine safety and effectiveness. Dr. Orenstein was the former director of the United States’ National Immunization Program.

“The problem with the natural immune response to influenza is that it is focused on the globular head of a protein that is called the hemagglutin or H protein.  The H protein is what attaches to cells and lets viruses enter.  Unfortunately, the natural immune response does not target a conserved area of the H protein but an area that can vary and hence the virus as it mutates can escape that immunity.

“The approach being developed here by the NIH does offer the potential of a ‘universal’ influenza vaccine.  These are animal studies so we are some way off for development and testing of a vaccine in humans. The technique is promising and a step in the right direction.  It should be studied further and hopefully will be successful.

“The H protein has a stalk that attaches to the main virus.  It turned out the 2009 pandemic H1N1 virus actually induced antibodies against the stalk and this has led other researchers, particularly at Mount Sinai, to develop approaches which appear promising in animals, to induce cross protective antibodies.  They do that by giving several doses of vaccine, each one with a different head but each one with the same stalk.

“I am not aware of ‘a successful heterosubtypic’ influenza vaccine in humans to date.  However, there is suggestive evidence that when humans are exposed to very different influenza viruses, that cross-protective immunity can be engendered.”

 

Declared interests (see GENeS register of interests policy):

No interests declared.

 

Reference:

Hemagglutinin-stem nanoparticles generate heterosubtypic influenza protection‘ by Graham et al, published in Nature Medicine on Monday, August 24, 2015.

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