1. H. Saito, Y. Kanamori, H. Ishikawa, Department of Microbiology, Keio University School of Medicine, Tokyo 160, Japan.
2. T. Takemori, Department of Immunology, National Institute of Infectious Diseases, Tokyo 162, Japan.
3. H. Nariuchi, Department of Allergology, Institute of Medical Science, University of Tokyo, Tokyo 108, Japan.
4. E. Kubota, Second Department of Oral and Maxillofacial Surgery, Kanagawa Dental College, Kanagawa 238, Japan.
5. H. Takahashi-Iwanaga, Department of Anatomy, School of Medicine, Hokkaido University, Sapporo 060, Japan.