A mutation that weakens the flu virus by making a flu-encoded protein defunct has been discovered by researchers at the University of Rochester Medical Center.
A rare and improbable mutation in a protein encoded by an influenza virus renders the virus defenseless against the body’s immune system. This University of Rochester Medical Center discovery could provide a new strategy for live influenza vaccines in the future.
A new approach to the live flu vaccine would be particularly advantageous right now after the Centers for Disease Control and Prevention stopped recommending use of the live attenuate flu vaccine, FluMist earlier this year. Several studies found that the pain-free nasal spray, which was used in about one-third of young children in the U.S., offered no protection to that especially vulnerable population. The flu shot, on the other hand, performed well and the CDC recommends using this vaccine in place of FluMist.
“There is a need to understand what’s happening with the existing live vaccine and potentially a need to develop a new one,” said David Topham, PhD, Marie Curran Wilson and Joseph Chamberlain Wilson Professor of Microbiology and Immunology at URMC and author of the study. “We proposed that the mutation we found could be used to create a live vaccine.”
The mutation weakens the flu virus by making the flu-encoded protein, called Non-Structural 1 (NS1), defunct. Flu virus needs NS1 to prevent interferon, the immune system’s front line against viruses, from alerting the host cell that it has been infected. Inhibiting interferon affords the virus time to multiply and spread before the immune system can mount an attack.