1. Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, 53 Shogoinkawara-cho, Sakyo-ku, Kyoto, Kyoto 606-8507, Japan
2. Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoinkawara-cho, Sakyo-ku, Kyoto, Kyoto 606-8507, Japan
3. Japanese Foundation for AIDS Prevention, 1-3-12 Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan
4. Department of Gynecology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka 569-8686, Japan
5. Central Institute for Experimental Animals, 1430 Nogawa, Miyamae-ku, Kawasaki, Kanagawa 216-0001, Japan