Mathematical Ecology Research Group, Department of Zoology, University of Oxford, Oxford, United Kingdom.|Department of Immunology, H. Lee Moffitt Cancer Center, Tampa, Florida, USA.|Division of Immunobiology and Center for Systems Immunology, Cincinnati Childrens Hospital Medical Center, Cincinnati, Ohio, USA.|Division of Immunobiology and Center for Systems Immunology, Cincinnati Childrens Hospital Medical Center, Cincinnati, Ohio, USA.|Department of Immunology, H. Lee Moffitt Cancer Center, Tampa, Florida, USA.|Wolfson Centre for Mathematical Biology, Mathematical Institute, University of Oxford, Oxford, United Kingdom.|Department of Integrated Mathematical Oncology, H. Lee Moffitt Cancer Center, Tampa, Florida, USA.|Mathematical Ecology Research Group, Department of Zoology, University of Oxford, Oxford, United Kingdom.