1. Division of HIV/AIDS and Sex-Transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing 102629, China
2. National Vaccine and Serum Institute, Beijing 101111, China
3. Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100006, China
4. National Rodent Laboratory Animal Resources Center, Institute for Laboratory Animal Resources, National Institutes for Food and Drug Control (NIFDC), Beijing 102629, China
5. Institute of Medical Biology, Chinese Academy of Medical Sciences, Kunming 650118, China