1. Department of Biochemistry; Shimane Medical University; Izumo Shimane 693 Japan
2. Department of Cellular Immunology; National Institute of Health; Shinagawa-ku Tokyo 141 Japan
3. Research Institute for Disease of Chest, Faculty of Medicine; Kyushu University; Fukuoka Fukuoka 812 Japan
4. Department of Oral Microbiology; Okayama University Dental School; Okayama Okayama 700 Japan