From the *Amgen Institute and Ontario Cancer Institute, Department of Medical Biophysics and Immunology, University of Toronto, M5G 2C1 Toronto, Ontario, Canada; ‡Ontario Cancer Institute, Department of Medical Biophysics and Immunology, University of Toronto, Toronto, Ontario, Canada; §Institute for Radiation and Cell Research, University of Wuerzburg, D-97078 Wuerzburg, Germany; ‖Samuel Lunenfeld Research Institute and Department of Medical Genetics, University of Toronto, Mount Sinai Hospital, Toronto, Ontario, Canada; and ¶Institute for Experimental Immunology, University of Zürich, 8091, Zürich, Switzerland(1997-09-15時点)