Jian Li1, Hong Wei2. 1. Institute of Immunology, PLA, Third Military Medical University (Army Medical University), Chongqing, 400038, China. 2. College of Animal Sciences and Technology, State Key Laboratory of Agricultural Microbiology, Key Laboratory of Agricultural Animal Genetics, Breeding, and Reproduction of the Ministry of Education & Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China. weihong63528@163.com.