1. Department of Immunology, School of Basic Medicine, Fourth Military Medical University , Xi’an 710032 , China
2. Department of Immunology, School of Basic Medical Sciences, Yan’an university , Yan’an 716000 , China
3. Department of Pathogenic Biology, School of Basic Medical Sciences, Yan’an university , Yan’an 716000 , China
4. Eighth Hospital of Xi’an , Xi’an 710061 , China
5. Center for Infectious Diseases, Second Affiliated Hospital of Air Force Medical University (Fourth Military Medical University) , Xi’an 710038 , China
6. Department of Microbiology, School of Basic Medicine, Fourth Military Medical University , Xi΄an 710032 , China
7. Department of Transfusion Medicine, Xijing Hospital, Fourth Military Medical University , Xi’an 710032, Shaanxi , China