1. Division of Immunity and Infection, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
2. Department of Laboratory Medicine, 1st Municipal People's Hospital of Guangzhou, 510180 Guangzhou, People's Republic of China
3. Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
4. Division of Microbiology, University of Leeds, LS2 9JT Leeds, United Kingdom