People's immune responses to infection with the 2009 H1N1 influenza pandemic virus included neutralizing antibodies effective against many flu virus strains.

Rafi Ahmed at Emory University in Atlanta, Georgia, Patrick Wilson at the University of Chicago in Illinois and their group analysed 86 antibodies made by immune cells from nine patients infected with H1N1. Surprisingly, 63% of the antibodies bound to flu viruses that had appeared before the 2009 pandemic. Some even worked against the 1918 pandemic virus and the H5N1 avian influenza virus. Three antibodies were generated from patients' cells and tested in mice. All three protected the animals against a lethal dose of H1N1, whether given before or after exposure. Such broadly protective antibodies — long sought, but elusive — could aid the design of a 'universal' flu vaccine, the team speculates.

J. Exp. Med. doi:10.1084/jem.20101352 (2011)