1. University of Alabama at Birmingham, Birmingham, Alabama, USA
2. AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
3. Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
4. Advanced BioScience Laboratories, Inc., Rockville, Maryland, USA
5. Bioqual, Rockville, Maryland, USA