1. Center for Vaccine Research, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213
2. Department of Infectious Diseases and Microbiology, School of Public Health, University of Pittsburgh, Pittsburgh, PA 15213
3. Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
4. Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110
5. Department of Microbiology, Harvard Medical School, Boston, MA, 02115
6. Department of Molecular Microbiology, Washington University, St. Louis, MO, 63110
7. Genome Engineering & Stem Cell Center (GESC@MGI), Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, MO 63110