1. Xenotransplantation Research Center, Seoul National University College of Medicine, Seoul, Korea
2. Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Korea
3. Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea
4. Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
5. Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Korea