1. M. Sugita, R. M. Jackman, S. M. Behar, M. B. Brenner, S. A. Porcelli, Lymphocyte Biology Section, Division of Rheumatology and Immunology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
2. E. van Donselaar and P. J. Peters, Department of Cell Biology and Institute of Biomembranes, Faculty of Medicine, University of Utrecht, Utrecht, Netherlands.
3. R. A. Rogers, Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA.