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.
"It has been suggested that the next pandemic strain may be derived from H5, H7, H9 or H2 influenza viruses. The preparation of the recombinant baculoviruses for the production of these antigens and the successful purifications gives us a great advantage in fighting against a potential influenza pandemic, if it derived from any of these strains," says Wang. "Starting from a stocked recombinant baculovirus bank, a closely matched vaccine can be massively produced within 2 weeks."
PSC has recently signed a Letter of Intent which will support commercial scale manufacturing with the capacity to produce 6 Million doses of monovalent pandemic vaccine per week.