1. Department of Microbiology and Immunology and the Molecular Biology Institute, Department of Medicine, University of California at Los Angeles, Los Angeles, California 90095
2. La Jolla Institute for Allergy and Immunology, San Diego, California 92121
3. Department of Microbiology and Molecular Genetics, Department of Medicine, University of California at Los Angeles, Los Angeles, California 90095
4. Division of Dermatology, Department of Medicine, University of California at Los Angeles, Los Angeles, California 90095
5. Pharmaceutical Research Laboratory, Kirin Brewery Co., Ltd., Gunma 370-12, Japan
6. Division of Digestive Diseases, Department of Medicine, University of California at Los Angeles, Los Angeles, California 90095