1. Institut Pasteur, Unité de Biologie des Régulations Immunitaires, Paris F-75015, France
2. INSERM, E 352, Paris F-75015, France
3. Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the Academy of Sciences of the Czech Republic, Prague, Czech Republic
4. Institut Pasteur, Unité de Génétique Moléculaire Bactérienne, Paris F-75015, France