1. 1Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
2. 2Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
3. 3Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, TN, USA
4. 4Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University, Nashville, TN, USA
5. 5Vanderbilt Genetics Institute, Vanderbilt University, Nashville, TN, USA
6. 6New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA