1. Department of Medical and Physiological Chemistry 4, University of Lund, S-221 00 Lund, Sweden.
2. Departments of Medicine and Microbiology, University of California, Los Angeles, CA 90024.
3. Division of Immunology, Beckman Research Institute of City of Hope, Duarte, CA 91010.
4. Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, CA 90509.
5. Research, Veterans Administration, Wadsworth Medical Center, Los Angeles, CA 90073, and Department of Medicine, University of California, Los Angeles, CA 90024.