The potential for developing a universal flu vaccine against both influenza A and B has become more feasible following a report by Crucell and the Scripps Institute that they have generated human monoclonal antibodies capable of disabling all influenza B virus strains. The three antibodies, designated CR8033, CR8071, and CR9114, recognize three different conserved epitopes on the surface of the influenza B viruses. Antibodies CR8033 and CR8071 recognize different conserved epitopes in the head region of the influenza B hemagglutinin (HA), whereas CR9114 binds a conserved epitope in the HA stem. In vivo studies showed that the antibodies were capable of protecting mice against otherwise lethal exposure to influenza B strains. Most notably, the CR9114 antibody provided protection against both A and B strains of the virus. The data is reported in Science, in a paper titled “Highly Conserved Protective Epitopes on Influenza B Viruses”.
Crucell-led scientists first reported back in 2008 on the development of fully human broad-spectrum influenza A antibodies that bind to a highly conserved epitope on the virus’ surface glycoprotein. Subsequent work carried out by the firm in collaboration with Scripps Research and the University of Hong Kong led to the development of broadly neutralizing antibodies against influenza A type 2 viruses. Both these classes of antibodies are capable of neutralizing just about the entire spectrum of influenza A viruses.
Development of broad-spectrum B-strain neutralizing antibodies means it could now be possible to generate a protective vaccine against every strain of influenza. “The identification and characterization of monoclonal antibodies with broad neutralizing activity against influenza B viruses, together with previously described broadly neutralizing antibodies against group 1 and group 2 influenza A viruses bring a universal therapy a step closer, and may guide the design of broadly protective vaccines,” comments Robert Friesen, Ph.D., study co-author who is deputy scientific director of the Crucell Vaccine Institute. “In particular, a vaccine that elicits antibodies targeting the CR9114 epitope may provide the ultimate goal of protection against all influenza A and B viruses.”