1. Laboratory of Medical Immunology 7544, State University Hospital, 2200 Copenhagen N, Denmark.
2. Steno Memorial Hospital and Haqdorn Research Laboratory, 2820 Gentofte, Denmark.
3. Department of Medicine, Division of Experimental Medicine, Tufts University School of Medicine, Boston, MA 02111.
4. Lymphocyte Laboratory, Department of Infectious Diseases, State University Hospital, 2200 Copenhagen N, Denmark.