A set of three antibodies, recently identified by researchers sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), hold the promise of better treatments and vaccines for the flu.
In a paper published in Science last week, the researchers noted that the antibodies offer broad protection against numerous strains of influenza when tests both in vitro and in mice. They operated by binding to neuraminidase (NA) proteins on the surface of flu viruses, which sets them apart from most flu vaccines. The majority stimulate responses against the surface protein known as hemagglutinin (HA) instead.
HA frequently changes as influenza evolves, one of the primary reasons there needs to be a new seasonal flu vaccine each year. NA proteins also change, but not nearly as frequently, making them an attractive target for longer-term protection.
After identifying and testing 45 different monoclonal antibodies (mAbs) from a volunteer sick with H3N2 influenza, the three in question were found to bind to NA proteins of the H3N2 strain, as well as other strains. Running with this, the researchers applied these mAbs to mice and infected them with different types of influenza viruses. Many were inhibited by the mAbs, and the treated mice survived even lethal doses of the H3N2 influenza virus.
Additional testing is necessary, but the researchers hope this could eventually lead to a new antiviral treatment or, at the least, inform the development of new flu vaccines designed to induce similar antibodies. Those vaccines could be longer-lasting and cover a broader scope of targets.