1. Department of Basic Medical Sciences, School of Medicine, Tsinghua University , Beijing 100084 , China
2. Institute for Immunology, Tsinghua University , Beijing 100084 , China
3. Tsinghua-Peking Center for Life Sciences , Beijing 100084 , China
4. Beijing Key Laboratory for Immunological Research on Chronic Diseases, Tsinghua University , Beijing 100084 , China
5. Immunology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center , New York, NY 10065 , USA
6. Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, Cornell University , New York, NY 10065 , USA