1. Laboratory of Primate Model, Experimental Research Center for Infectious Disease, Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan.
2. Present address: LMM, NIAID, NIH, Building 4, Rm B1-33, 4 Center Drive, Bethesda, Maryland 20892.
3. Shionogi Institute for Medical Science, 2-5-1 Mishima, Settsu, Osaka 566-0022, Japan.
4. Present address: Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan.
5. Present address: Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of Maryland, Baltimore, Maryland.