1. Department of Microbiology and Immunology, School of Medicine, University of Maryland—Baltimore, 655 W. Baltimore Street, Baltimore, Maryland 21201
2. Cardiff School of Biosciences, Cardiff University, Cardiff, Wales CF10 3TL, United Kingdom
3. Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109
4. Department of Biomedical Sciences, Dental School, University of Maryland—Baltimore, 650 W. Baltimore Street, Baltimore, Maryland 21201