1. Division of International Collaboration Research and Tokyo Joint Laboratory, Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto, Japan
2. Department of Microbiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
3. National Hospital of Tropical Diseases, Hanoi, Vietnam
4. Hanoi Medical University, Hanoi, Vietnam
5. AIDS Clinical Center, National Center for Global Health and Medicine, Tokyo, Japan