Flu Virus Evolution Is More Predictable Than Expected | Chemical & Engineering News
Volume 91 Issue 47 | p. 27 | Concentrates
Issue Date: November 25, 2013

Flu Virus Evolution Is More Predictable Than Expected

Changes to only seven amino acids are responsible for most vaccine-evading changes over a 35-year period
Department: Science & Technology
News Channels: Biological SCENE
Keywords: Influenza, flu, vaccine, hemagglutinin, evolution, mutations, seasonal
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In this model, flu hemagglutinin is shown as a trimer (white, black, and gray). The receptor binding site is yellow, and the seven key amino acids are shown in red.
Credit: Science/AAAS
Spacefill diagram of influenza hemagglutinin trimer, showing in red those amino acids that, when mutated, are most responsible for antibody evasion.
 
In this model, flu hemagglutinin is shown as a trimer (white, black, and gray). The receptor binding site is yellow, and the seven key amino acids are shown in red.
Credit: Science/AAAS

Every year brings a new version of the vaccine for seasonal flu, because the virus can mutate and evade antibodies already present in the body. It might seem as though scores of mutations have contributed to that escape artistry. According to a new report, however, mutations to just seven amino acids are the ones that truly mattered over a 35-year period (Science 2013, DOI: 10.1126/science.1244730). All seven of these amino acids are in hemagglutinin, a glycoprotein on the surface of the flu virus. Six of the seven align next to one another on the protein’s receptor binding site. Derek J. Smith of the University of Cambridge, Ron A. M. Fouchier of Erasmus Medical Center in the Netherlands, and colleagues made this discovery in the H3N2 flu subtype, which contributes to seasonal outbreaks. In strains that emerged between 1968 and 2003, five of the seven key amino acids were involved in the strain’s evolution more than once. “These findings have potentially far-reaching consequences for understanding the evolutionary mechanisms that govern influenza viruses,” the team writes.

 
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