1. Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
2. Department of Pathology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
3. Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland
4. Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
5. Howard Hughes Medical Institute, Baltimore, Maryland