1. Division of Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, San Diego, California, USA
2. Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
3. Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
4. University of California San Diego School of Medicine, La Jolla, San Diego, California, USA