1. School of Life Sciences, Anhui University, Hefei, China.
2. Southern China United Vaccine Institute, Guangzhou, China.
3. State Key Laboratory of Respiratory Disease, Sino-French Hoffmann Institute, Guangzhou Medical University, Guangzhou, China.
4. The State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China.