A team of scientists, building on their work with influenza A viruses, have discovered a means to neutralize influenza B viruses that could pave the way for a more effective universal vaccine.
The team from the Scripps Research Institute, the Crucell Vaccine Institute, Gustav Wieds Vej and the University of Hong Kong previously found that monoclonal antibodies could neutralize influenza A by binding to a highly specific region on the virus stem known as an epitope, according to Phys.org.
The scientists then switched their focus to three human monoclonal antibodies that they knew protected from potentially lethal infections by influenza B. They found that two of the antibodies bind to epitopes in the head region of the influenza B hemagglutinin. The third antibody, known as CR9114, binds to the epitope in the influenza B hemagglutinin stem and provides protection from both forms of the virus.
“Several structures were solved using the facilities in order to study the interaction of CR9114 with group 2 influenza A viruses,” Cyrille Dreyfus, a team member from SRI and a lead author of the study, said, Phys.org reports. “These structures allowed us to confirm the broad neutralizing activity of CR9114.”
The study also concluded that the three monoclonal antibodies did not compete to bind at the same sites on the virus and therefore recognize different epitopes. The other two antibodies prevent the release of viral progeny from already infected cells. CR9114 uses an entirely different mechanism. It blocks infection by preventing the low pH conformational changes that fuse the viral and endsomal membranes during the entry process.
“Future directions are to apply this knowledge toward the development of improved therapies and vaccines such as development of monoclonal antibody therapies, and the design of small molecules that target the weak point in the virus defense,” Dreyfus said, according to Phys.org.