October 2012

Antibodies Protect Against Range of Flu Viruses

Scientists isolated antibodies that protect mice against several deadly flu viruses. The accomplishment is a step toward a flu vaccine that can protect against multiple viral strains for several years.

Flu is caused by influenza viruses, which infect the nose, throat and lungs. These viruses constantly change, or mutate. Researchers need to reformulate the flu vaccine each year to match new strains. If a vaccine could prompt the body to make antibodies that latch onto unchanging parts of the virus, it might provide long-lasting protection.

NIH-funded researchers previously isolated antibodies that target a wide range of influenza “type A” viruses. Type A viruses are responsible for avian flu, the 1918 pandemic flu and seasonal flu.

In the new study, scientists took a similar approach to find antibodies that neutralize influenza “type B” viruses. Influenza B viruses have received less attention. They’re less likely to cause worldwide outbreaks. But they can cause seasonal flu.

Researchers collected and tested antibodies from people recently vaccinated for seasonal flu. The scientists identified 3 antibodies that latched onto a specific region on different influenza B viruses. One of these 3 also bound type A viruses.

All 3 antibodies protected mice from deadly influenza B viruses. The broader-binding one also guarded against lethal doses of 2 types of influenza A viruses.

“To develop a truly universal flu vaccine or therapy, one needs to be able to provide protection against influenza A and influenza B viruses,” says one of the head authors, Dr. Ian A. Wilson of the Scripps Research Institute. “With this report, we now have broadly neutralizing antibodies against both.”