1. Laboratory Animal Research Center, Institute of Medical Science, University of Tokyo, Shirokanedai, Minato-ku, Tokyo
2. Department of Internal Medicine, Institute of Medical Science, University of Tokyo, Shirokanedai, Minato-ku, Tokyo and Department of Parasitology, Shinshu University School of Medicine, Matsumoto, Japan
3. Department of Allergology, Institute of Medical Science, University of Tokyo, Shirokanedai, Minato-ku, Tokyo
4. Department of Internal Medicine, Institute of Medical Science, University of Tokyo, Shirokanedai, Minato-ku, Tokyo
5. Department of Pathology, Kansai Medical University, Moriguchi, Osaka, Japan