1 Department of Medicine, Division of Infectious Diseases, University of Alberta, Edmonton, AB, Canada.
2 Intramural Research Training Award Program, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD.
3 Pulmonary Branch, Division of Intramural Research, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD. Electronic address: Kevin.Fennelly@nih.gov.