1. Center for Neurovirology and Cancer Biology, Temple University, Philadelphia, Pennsylvania 19122
2. Department of Pathology and Laboratory Medicine, School of Medicine, MCP Hahnemann, Philadelphia, Pennsylvania 19102
3. Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
4. The Wistar Institute, Philadelphia, Pennsylvania 19104
5. Pharmaceutical Division, Ajinomoto Co., Inc., Tokyo 104, Japan