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Flu prevention grabs virus by the neck

It will take three years to prove the antibodies safe, but the result could be a single vaccine against all types of H5 flu, and the scientists are now going after the H3 strains as well.

How was it possible to create a single antibody effective against all known types of flu -- including bird flu, the 1918 influenza and the annual flu bugs you now get a shot for?

By focusing on the part of the virus that does not readily mutate, known as the stem end or neck. (On the diagram, offered by the lead researcher, look closely at the structure called the hinge and the fusion peptide below it.)

Wayne Marasco of Harvard and the Dana-Farber Cancer Institute led the team, which included groups of researchers at La Jolla, Calif. and Atlanta, in creating monoclonal antibodies to fight many different strains of flu.

Some 19 authors are on the resulting paper, now at Nature Structural and Molecular Biology.

All these type of flu bugs are known as H5 Type hemaglutinin. Binding a readily-produced antibody to the stem end or neck of the H5 keeps it from making changes necessary for it to invade another cell, meaning it can't infect other cells or reproduce itself inside that cell.

A CDC scientist who worked on the project, Ruben Donis, noted that the human monoclonal antibody they created not only protected mice three days after their injection with bird flu, but also protected them against other lethal flu strains.

Creating a chemical key to pick the virus' lock meant first getting the crystal structure right. In other words a 3-D view of the bug was necessary. Then a "highly conserved pocket" of the structure was found, and when the antibody was inserted here the virus was no longer able to mutate.

Current vaccines use a dead or weakened virus, a methodology pioneered in the 19th century. The new technique uses a recombinant purified protein instead.

Thus you have a technique that can not only affect a cure, but which can vaccinate as well.

It will take three years to prove the antibodies safe, but the result could be a single vaccine against all types of H5 flu, and the scientists are now going after the H3 strains as well.

Marasco told The New York Times they are also looking for a stem in the B strain of flu that might be attacked in the same way.

The best news is that, as a treatment for things like a possible bird flu pandemic, the antibodies only require safety testing by the FDA before they can be deployed. Marasco hopes supplies of the cure can be stocked between now and the development of a vaccine.