1. Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
2. Infectious and Inflammatory Disease Center, Sanford Burnham Medical Research Institute, La Jolla, California, USA
3. Department of Immunology, University of Washington School of Medicine, Seattle, Washington, USA
4. Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
5. Department of and Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA