About the Authors
Department of Microbiology and Institute for Immunology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
GlaxoSmithKline, Department of Safety Assessment, Immunologic Toxicology, King of Prussia, Pennsylvania, United States of America
The authors have declared that no competing interests exist.
Conceived and designed the experiments: AC EJW. Performed the experiments: AC JMA SDB KLN. Analyzed the data: AC. Wrote the paper: AC EJW.