1. Department of Microbiology and Immunology, University of Kentucky College of Medicine, Lexington, Kentucky 40536-02981;
2. Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 598402; and
3. Division of Molecular Biology and Genetics, Department of Oncological Sciences, University of Utah, Salt Lake City, Utah 841323