1. Division of Bacteriology, Department of Infection and Immunity, Jichi Medical University, 3311-1, Yakushiji, Shimotsuke-shi, Tochigi 329-0498, Japan
2. Choka Research Institute, vaxxinova Japan K.K., 809, Choka, Nikko-shi, Tochigi 321-1103, Japan
3. Department of Nutritional Science, Faculty of Human Life Science, Shokei University, 2-6-78, Kuhonji, Chuo-ku, Kumamoto-shi, Kumamoto 862-8678, Japan
4. Tamano Institute of Health and Human Services, 1-1-20 Chikko Tamano-shi, Okayama 706-0002, Japan