New pill shows early promise for blocking many strains of flu
By Robert F. ServiceMar. 7, 2019 , 2:00 PM
The flu season is at its height in the Northern Hemisphere, but—as many are discovering—seasonal flu vaccines don’t always provide complete protection, because unexpected flu strains show up unannounced. Now, researchers report they’ve developed an experimental oral medicine that protects mice from a wide range of influenza viruses. If it works in humans, it could lead to a new pill to fight one of the deadliest infections humanity faces.
Every year, influenza causes a severe illness in some 3 million to 5 million people worldwide and kills up to 650,000, according to the World Health Organization. Medicine’s primary defense against the flu is the seasonal flu vaccine, an injected cocktail of killed viruses designed to prod the immune system to produce antibodies. Those antibodies disable the flu strains deemed most likely to circulate that season. But sometimes unforeseen strains end up spreading instead, rendering the vaccine less effective.
Normally, antibodies target an individual strain of flu. But in 2008, researchers discovered a class of so-called broadly neutralizing antibodies (bnAbs) in humans that can bind to and disable multiple flu strains at once. Detailed studies of one the best of these bnAbs, called CR6261, showed it binds to the stem portion of a mushroom-shaped hemagglutinin (HA) protein on the surface of the virus. This portion of the protein is virtually identical in multiple flu strains and is essential for enabling the virus to fuse with the membranes of cells it infects.
Source: https://www.sciencemag.org/news/2019/03/new-pill-shows-early-promise-blocking-many-strains-flu - https://www.sciencemag.org/news/2019/03/new-pill-shows-early-promise-blocking-many-strains-flu
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