1. Laboratory of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, the University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan
2. Veterinary Medical Center, Graduate School of Agricultural and Life Sciences, the University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan
3. Laboratory of Biomedical Science, Graduate School of Agricultural and Life Sciences, the University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan
4. Department of Molecular Pathology, Shinshu University Graduate School of Medicine, Asahi 3-1-1, Matsumoto, Nagano 390-8621, Japan
5. Laboratory of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, the University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan