The next flu pandemic could happen any time," says Keyang Wang, a scientist at Protein Sciences Corporation (PSC) and a researcher on the study. "The most effective method to control such an outbreak is the widespread use of a vaccine, preferably in a pro-active manner, so that the immune system is primed prior to actual virus exposure. The traditional egg-based method requires 3 to 6 months to develop the vaccine. With our cell-based method, as soon as the pandemic strain is identified, a matched vaccine can be massively produced within 4 weeks."
The vaccine strategy pursued by Protein Sciences, known commercially as FluBlok, uses a purified protein from the surface of the virus called hemagglutinin (the H part of a virus' designation, like H5N1 for the current avian influenza) to elicit an immune response to a specific strain of influenza. The protein is produced by first extracting the genes responsible for the production of hemagglutinin from the influenza virus and inserting them into a baculovirus. Specific host cells are then infected with the baculovirus and produce recombinant hemagglutinin (rHA). Phase II clinical trials show that rHA-based vaccines produced using this system are safe, elicit immunity equal to or greater than egg-based vaccines, and are 100% effective in the prevention of cell culture confirmed influenza.
Wang and his colleagues report the successful production of rHA from 4 strains of influenza that scientists believe to be likely the cause of the next pandemic (H5, H7, H9, and H2) at a level where manufacturing costs are expected to be equal to or less than that of traditional egg-based vaccines.
Contact: Jim Sliwa
American Society for Microbiology