1. Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
2. Viral Pathogenesis Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
3. Immunology Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
4. Morehouse School of Medicine, Atlanta, Georgia, USA