Cambridge Institute of Therapeutic Immunology & Infectious Disease, Cambridge Institute of Therapeutic Immunology & Infectious Disease, Cambridge Institute of Therapeutic Immunology & Infectious Disease, Cambridge Institute of Therapeutic Immunology & Infectious Disease, University of Glasgow - Institute of Biodiversity, Animal Health and Comparative Medicine, Cambridge Institute of Therapeutic Immunology & Infectious Disease, MRC - University of Glasgow Centre for Virus Research, MRC – Laboratory of Molecular Biology, Independent, University of Cambridge - Department of Medicine, University of Cambridge - Department of Medicine, University of Cambridge - Department of Medicine, MRC – Laboratory of Molecular Biology, MRC - University of Glasgow Centre for Virus Research and Cambridge Institute of Therapeutic Immunology & Infectious Disease