Sunday, September 13, 2009

Fooling the Flu

Conventional methods of flu vaccine creation involve prediction of dominant haemagglutinin and neraminidase. Haemagglutinin works to “deflect the immune attack away from more vulnerable parts of the virus”, acting like a decoy. For this reason, vaccines are now being designed to contain only conserved proteins instead of entire viruses. The protein of greatest interest is M2, which has been investigated by no less than ten companies. They have been exploring the use of a certain part of M2—M2e—that protrudes from the protein. Researchers have attached M2e, which does not elicit a strong immune reaction when injected, to molecules that would elicit such a response otherwise.

Merck, Acambis, and VaxInnate have all reached clinical trials. However, Merck abandoned its efforts in 2007 after they found that the M2e hybrid only resulted in antibody production when pain-causing adjuvants were added. Work at Acambis slowed when it was absorbed by Sanofi-Pasteur. In 2008, their M2e vaccine with two adjuvants produced antibodies and no major side effects in 90% of subjects. The head of VaxInnate claims that the company has developed a vaccine with zero adjuvants and an identical antibody response (as compared to Merck and Acambis). VaxInnate will move ahead first, but further trials are currently stalled as authorities take on swine flu challenges.

Research at Oxford is going in a different direction, instead of aiming to stimulate the creation of antibodies, they are focusing on cell-mediated immunity. Their approach is to modify MVA, a variety of “the virus used for decades as a smallpox vaccine”, which must be a reference to vaccinia, in order to create M2 as a whole.

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