1. Center for Microbial Pathogenesis, the Research Institute at Nationwide Children's Hospital and Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, USA
2. Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, USA
3. Research Service Veterans Affairs Medical Center, Decatur, Georgia, USA, and Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA