1. C. L. Karp, J. M. Ahearn, P. J. Cuomo, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
2. M. Wysocka and G. Trinchieri, Wistar Institute of Anatomy and Biology, Philadelphia, PA 19104, USA.
3. L. M. Wahl, Laboratory of Immunology, National Institute of Dental Research, National Institutes of Health, Bethesda, MD 20892, USA.
4. B. Sherry, Picower Institute for Medical Research, Manhasset, NY 11030, USA.
5. D. E. Griffin, Department of Molecular Microbiology and Immunology, Johns Hopkins University School of Hygiene and Public Health, Baltimore, MD 21205, USA.