1. Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA.
2. Laboratory of Humoral Response to Pathogens, Department of Immunology, Institut Pasteur, France.
3. Division of Biology, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA.
4. Howard Hughes Medical Institute (HHMI), The Rockefeller University, New York, NY 10065, USA.