1. Department of Pathogenic Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University, Xi’an 710061, China
2. Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi’an 710061, China
3. Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, National Poultry Laboratory Animal Resource Center, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150069, China