EpidemicsNatural antibody brings universal flu vaccine closer

A universal flu vaccine in the offing // Source: yle.fi

Annually changing flu vaccines with their hit-and-miss effectiveness may soon give way to a single, near-universal flu vaccine, according to a new report from scientists at the Scripps Research Institute and the Dutch biopharmaceutical company Crucell. They describe an antibody which, in animal tests, can prevent or cure infections with a broad variety of influenza viruses, including seasonal and potentially pandemic strains.
The finding, published in the journal Science Express on 7 July 2011, shows the influenza subtypes neutralized with the new antibody include H3N2, strains of which killed an estimated one million people in Asia in the late 1960s.

“Together this antibody and the one we reported in 2009 have the potential to protect people against most influenza viruses,” said Ian Wilson, who is the Hansen Professor of Structural Biology and a member of the Skaggs Institute for Chemical Biology at Scripps Research, as well as senior author of the new paper with Crucell’s chief scientific officer Jaap Goudsmit.

A Scripps Research Institute’s release reports that Wilson’s laboratory has been working with Crucell scientists since 2008 to help them overcome the major shortcoming of current influenza vaccines: They work only against the narrow set of flu strains that the vaccine makers predict will dominate in a given year, so their effectiveness is temporary. In addition, current influenza vaccines provide little or no protection against unforeseen strains.

These shortcomings reflect a basic flu-virus defense mechanism. The viruses come packaged in spherical or filamentous envelopes that are studded with mushroom-shaped hemaglutinin (HA) proteins, whose more accessible outer structures effectively serve as decoys for a normal antibody response. “The outer loops on the HA head seem to draw most of the antibodies, but in a given strain these loops can mutate to evade an antibody response within months,” said Wilson. Antiviral drugs aimed at these and other viral targets also lose effectiveness as flu virus populations evolve.

“The major goal of this research has been to find and attack relatively unvarying and functionally important structures on flu viruses,” said Damian Ekiert, a graduate student in the Scripps Research Kellogg School of Science and Technology who is working in the Wilson laboratory. Ekiert and Crucell’s Vice President for Antibody Discovery Robert H. E. Friesen are co-first authors of the Science Express report.

By sifting through the blood of people who had been immunized with flu vaccines, Goudsmit and his colleagues several years ago discovered an antibody