1. Section of Immunobiology, Yale University School of Medicine, New Haven, CT 06510.
2. Division of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510.
3. Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06510.
4. Division of Allergy and Clinical Immunology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510.