1. Université d' Orléans, Centre national de la Recherche Scientifique (CNRS), Molecular Immunology and Embryology, 45071 Orléans, France
2. Biomedical Research Foundation, SBF, 9548 Matzingen, Switzerland
3. Institute of Infectious Disease and Molecular Medicine, University of Cape Town, 7925 Cape Town, South Africa
4. Schering Plough Inc., 69571 Dardilly, France