1. Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California 92037
2. Immuno Technology Section, Laboratory of Immunology, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892
3. Hepatitis Viruses Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892