1. From the University of Montreal, Centre de Recherche Louis-Charles Simard, Notre-Dame Hospital, and the Department of Obstetrics and Gynecology, Montreal, Quebec, Canada; the Institute for Virus Research, Kyoto University, Kyoto, Japan; Kitasato University, Kitasato, Sagamihara, Kanagawa, Japan; and Immunex Research and Development Corp, Seattle, WA.