1. Service of Immunology and Allergy, Department of Medicine, Centre Hospitalier, Universitaire Vaudois, Lausanne, University of Lausanne, CH-1011 Lausanne, Switzerland
2. Swiss Vaccine Research Institute, 1011 Lausanne, Switzerland
3. Institut de Génétique Moléculaire de Montpellier, Centre National de la Recherche Scientifique 5535, 34293 Montpellier, France
4. Université Montpellier I and II, 34967 Montpellier, France