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.)
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.
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.