1. Department of Molecular Biology and Biochemistry,
2. Institute for Immunology, and
3. Department of Microbiology, Immunology, and Molecular Genetics, College of Medicine, University of Kentucky, Lexington, Kentucky; and
4. Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon
5. Department of Statistics, University of California, Irvine, Irvine, California;