Catching a Moving Target

Broadly neutralizing antibodies could help create an influenza vaccine that would not have to be updated. Seasonal influenza viruses persist as important human pathogens because of their ability to constantly change the structure of a key protein, the viral hemagglutinin, which is needed to invade cells and is a major target of immune defenses. This shiftiness dictates a hefty vaccine regimen: Ideally, patients are vaccinated each year with updated formulations that protect them against new virus strains. Recent research, however, has raised the possibility of developing a universal flu vaccine that would not have to be updated. In mice and humans, researchers have identified “broadly neutralizing antibodies” (bnAbs) ( 1 – 8 ) that have the potential to make influenza less of a moving target. Two papers in this issue, by Ekiert et al. ( 9 ) on page 843 and Corti et al. ( 10 ) on page 850, describe novel bnAbs that protect animals against influenza and show how they bind to the viral hemagglutinin protein.