Technology.am (May 4, 2009) — Virginia Tech virologist is developing a platform for a flu vaccine that allows rapid modifications to meet new strains of flu.
Chris Roberts’ the associate professor in biomedical sciences and pathobiology has been working on a flu vaccine for the elderly, but now he is more motivated than ever to speed development of his cell culture-based vaccine technology that is more rapid than the egg-based growth system presently used to create vaccines.
Influenza is an enveloped virus. It obtains its envelope or membrane as it buds from the surface of the host cell it has invaded.
Roberts is using this practice against the virus – introducing membrane-bound immune-system stimulatory molecules such as cytokines into cells in such a way that the virus will incorporate them as part of its envelope. “Using this approach, inactivated influenza vaccines can be created that have enhanced immunogenicity, meaning they can boost our immune response to the vaccine and hopefully provide better protection against invading viruses,” Roberts said.
Normally, cytokines are secreted proteins that boost and direct the immune system’s response to inflammation and infections. When a foreign particle gets into the body, the body ultimately responds by stimulating, B cells to secrete anti-viral antibodies, cytotoxic T cells to kill infected host cells, and helper T cells to regulate and control the response of both cell types.
Antibodies work by recognizing and binding to specific components of the virus such as the glycoproteins on the surface of the virus. This serves to neutralize the ability of the virus to infect cells.
A vaccination introduces weakened or killed forms of a virus so that the body recognizes the pathogen and begins producing antibodies to fight it. These antibodies are then ready to fight off infection should they encounter the virus.
Roberts’ vaccine goes a step further and provides an immune-boosting signal on the surface of the vaccine.
Presently, vaccines are made from eggs and it generally takes one or two special pathogen-free eggs per dose. It also takes four to five months to prepare enough doses of the vaccine for a given year. Several companies are actively working to develop cell culture based vaccines for flu, such as is already used for polio and chickenpox vaccines, for instance.
Roberts’ approach, to have the virus clothed in its own vaccine, capitalizes on the use of cell culture based systems for vaccine production.