About the Authors
Department of Virology, Faculty of Medicine, Imperial College London, London, United Kingdom
The authors have declared that no competing interests exist.
Conceived and designed the experiments: GWM MH BJF BJM DCJC GLS. Performed the experiments: GWM MH BJF BJM DCJC. Analyzed the data: GWM MH BJF BJM DCJC GLS. Wrote the paper: GWM MH BJF GLS.