1. Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
2. Electron Microscopy Laboratory, Advanced Technology Program, SAIC-Frederick, Inc, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA.
3. AIMM Therapeutics, Academic Medical Center, Amsterdam, Netherlands.
4. National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, China, 361005.