1 Laboratory of Retroviruses, US Food and Drug Administration, Silver Spring, MD 20993, USA. Electronic address: arifa.khan@fda.hhs.gov.
2 Institut für Virologie und Immunbiologie, Universität Würzburg, Würzburg, Germany.
3 Unit of Epidemiology and Physiopathology of Oncogenic Viruses, Institut Pasteur, Paris, France; Centre National de la Recherche Scientifique, CNRS UMR3569, Paris, France.
4 Biology Department, Boston College, Chestnut Hill, MA 02467, USA.
5 Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, USA.
6 Department of Biochemistry, National Veterinary Research Institute, Puławy, Poland.
7 Institute of Virology, Technische Universität Dresden, Dresden, Germany.
8 Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
9 Research Program Infection, Inflammation and Cancer, German Cancer Research Center (DFKZ), Heidelberg, Germany.
10 Instituto Nacional de Câncer and Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
11 Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA.