A team of US researchers have discovered three antibodies that could enable the development of treatments and vaccines for influenza (flu) virus.

The team involved scientists from Washington University School of Medicine in St Louis, Scripps Research and Icahn School of Medicine at Mount Sinai in New York City. The National Institute of Allergy and Infectious Diseases (NIAID) supported the research.

During the research, the team isolated monoclonal antibodies five days after the onset of symptoms in a person infected with H3N2 flu.

The researchers tested 45 monoclonal antibodies, finding three that bound to neuraminidase (NA) proteins present on the surface of an H3N2 virus strain.

Further testing showed that the three antibodies also bound to NA proteins on several other influenza virus types.

NA proteins are required for virus replication, freeing newly formed viruses from infected cells and allowing them to infect new cells.

When tested in mice administered with a lethal dose of the flu virus, all three antibodies were observed to be effective against multiple strains. One of the antibodies, 1G01, was effective against all 12 strains tested.

The findings are expected to enable a universal vaccine and a drug to treat severe flu cases. Currently, the team is working to develop vaccines and treatments that could offer long-lasting immunity.

Washington University pathology and immunology assistant professor Ali Ellebedy said: “Neuraminidase has been ignored as a vaccine candidate for a long time. These antibodies tell us that it should not have been overlooked.

“Now that we know what a broadly protective antibody to neuraminidase looks like, we now have an alternative approach to start designing novel vaccines that induce antibodies like this. And that could be really important if we are going to figure out how to design a truly universal vaccine.”