1. Mucosal Immunity Laboratory, Department of Gynecology, Obstetrics and Medical Genetics, Central University Hospital of Vaud (CHUV), Lausanne 1011, Switzerland
2. Mucosal Immunology Laboratories, Department of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital
3. Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02129