1. Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan
2. Laboratory Animal Research Center, Toyama Medical and Pharmaceutical University, Toyama 930-0152, Japan
3. College of Medical Technology, Kyoto University, Kyoto 606-8507, Japan
4. Laboratory of Viral Control, Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan
5. Department of Microbiology and Immunology, Nippon Medical School, Tokyo 113-8602, Japan