1. Department of Microbiology & Immunology, Emory Vaccine Center, Emory University School of Medicine, 1510 Clifton Road, Room 3086 Rollins Research Center, Atlanta, GA 30322, USA
2. Agriculture Ministry Key Laboratory of Veterinary Public Health, Harbin Veterinary Research Institute, CAAS, 427 Maduan Street, Harbin 150001, China
3. Central Laboratory, Tangdu Hospital, The Fourth Military Medical University, No. 1 Xinsi Road, Xi'an 710038, China
4. Department of Infectious Diseases, Tangdu Hospital, The Fourth Military Medical University, No. 1 Xinsi Road, Xi'an 710038, China