1. Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia.
2. Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia.
3. Divisions of Microbiology and Immunology, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia.