1. 1Crick Worldwide Influenza Centre, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
2. 2Mass Spectrometry and Proteomics Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
3. 3MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK