Department of Pathogenic Biology, The Fourth Military Medical University, Xian, 710032, P. R. China. liu_xuewu@hotmail.com.|Department of Pathogenic Biology, The Fourth Military Medical University, Xian, 710032, P. R. China. celina_xiao@163.com.|Department of Pathogenic Biology, The Fourth Military Medical University, Xian, 710032, P. R. China. liangjiao_18@163.com.|Department of Pathogenic Biology, The Fourth Military Medical University, Xian, 710032, P. R. China. MACNK@163.com.|Department of Pathogenic Biology, The Fourth Military Medical University, Xian, 710032, P. R. China. yinghlzb@fmmu.edu.cn.|Department of Pathogenic Biology, The Fourth Military Medical University, Xian, 710032, P. R. China. 977753561@qq.com.|Department of Pathogenic Biology, The Fourth Military Medical University, Xian, 710032, P. R. China. 37762810@qq.com.|Department of Pathogenic Biology, The Fourth Military Medical University, Xian, 710032, P. R. China. zhikaixu@fmmu.edu.cn.|Department of Pathogenic Biology, The Fourth Military Medical University, Xian, 710032, P. R. China. zhaoya@fmmu.edu.cn.