1. Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA.
2. Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA.
3. Rocky Mountain Veterinary Branch, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA.
4. Department of Microbiology and Immunology, Division of Virology, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo.
5. ERATO Infection-Induced Host Responses Project, Japan Science and Technology Agency, Saitama, Japan.