1. Department of Immunology, Hebei Medical University, Shijiazhuang, China
2. Key Laboratory of Immune Mechanism and Intervention on Serious Disease in Hebei Province, Shijiazhuang, China
3. Division of Infectious Diseases, Allergy and Immunology, Departments of Internal Medicine and Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, MO, USA