1. Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
2. Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
3. Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
4. Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
5. Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon, USA