H1 Haemagglutinin receptor complexes

An estimated 20 million people died in the influenza pandemic of 1918. The 1918 virus also spread to swine and continues to cause swine influenza outbreaks. We report here the crystal structures of the haemagglutinins (HAs) of the 1918 virus, the first swine influenza virus of 1930, and the human virus of 1934. We also present structures of HAs complexed with receptor analogues that show how human and swine HAs recognise human and avian receptors, and we deduce the receptor-binding properties of the 1918 HA which, in combination with novel antigenicity, contributed to the explosive nature of the 1918 pandemic. (C) 2004 Published by Elsevier B.V.