Scientists isolate antibodies that protect against various flu viruses
The research, published in the online edition of Science on Thursday, may help scientists to progress toward a universal flu vaccine that could be used during severe outbreaks. The antibodies can provide clues for designing a vaccine that could protect against multiple flu viruses on a long-term basis.
"To develop a truly universal flu vaccine or therapy, one needs to be able to provide protection against influenza A and influenza B viruses, and with this report we now have broadly neutralizing antibodies against both," Ian A. Wilson, the senior investigator of the study, said.
The three antibodies - CR8033, CR8071 and CR9114 - protected mice against typically lethal doses of the two main strains of influenza B. CR9114 also protected the mice against influenza A viruses by binding to a site on the hemagglutinin protein's stem, preventing the viruses from sticking to cells vulnerable to the flu.
"It prevents the hemagglutinin protein from undergoing the shape-change needed for the virus to fuse to the outer membrane of a host cell," Cyrille Dreyfus, the lead author of the study, said. "This appears to be a real weak point of the virus, because this epitope is highly conserved among influenza A subtypes as well as influenza B."
The viral epitope the CR9114 antibody connected with will now be studied extensively as a possible target for future universal therapies and vaccines. The antibody is the only known antibody found that broadly neutralizes influenza A and B strains.