1. Department of Preventive and Therapeutic Research for Infectious Diseases, Course of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
2. Department of AIDS Research, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
3. Molecular Cell Science Laboratory, RIKEN, Saitama, Japan
4. International Research Center for Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
5. AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan