Affiliation: | aDepartment of Microbiology, College of Physicians and Surgeons, Columbia University, New York, New York, 10032;bBristol-Myers Squibb Pharmaceutical Research Institute, Seattle, Washington, 98121;cInstitut für Medizinische Virologie der Universität Heidelberg, Im Neuenheimer Feld 324, 69120, Heidelberg, Federal Republic of Germany;dDepartment of Genetics, University of Georgia, Athens, Georgia, 30602 |