1. Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, California, USA
2. Department of Infectious Diseases, J. Craig Venter Institute, La Jolla, California, USA
3. Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
4. Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
5. Department of Medicine, University of California, San Diego, San Diego, California, USA
6. Department of Biology, San Diego State University, San Diego, California, USA