1. Center for Infectious Disease Research, Department of Basic Medical Sciences, Tsinghua University School of Medicine, Beijing, Haidian, China
2. Department of Pediatrics, Washington University School of Medicine in St. Louis, St. Louis, MO, United States
3. Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO, United States
4. Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO, United States