1. Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA.
2. Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
3. Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
4. David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
5. Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
6. Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA.