1. From the Laboratoire d'Immunologie, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Quebec H2W 1R7, Canada
2. Department of Medicine, Division of Experimental Medicine, McGill University, Montreal, Quebec H3A 1A3, Canada
3. The Gladstone Institute of Virology and Immunology, University of California at San Francisco, San Francisco, California 94141
4. Division of Hematology and Oncology, Microbiology, and Immunology, University of California at San Francisco, San Francisco, California 94143
5. Departments of Medicine, Microbiology, and Immunology, University of California at San Francisco, San Francisco, California 94143
6. Department of Microbiology and Immunology, McGill University, Montreal, Quebec H3A 1A3, Canada
7. Département de Microbiologie et d'Immunologie, Université de Montréal, Montréal, Quebec H3C 3J7, Canada