1. Department of Infectious Diseases, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
2. Department of Viral Infection, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.
3. Department of Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.