1. Gastroenterology Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
2. Program in Immunology, Division of Medical Sciences
3. Department of Anatomy and Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY 11203
4. Division of Hematology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
5. Division of Developmental Immunology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121