1. Departments of Pharmacology (M.C.E., H.J.D., J.L.R., C.J.S.), Nova Scotia, Canada B3H 4R2
2. Microbiology and Immunology (I.D.H.), Dalhousie University, Halifax, Nova Scotia, Canada B3H 4R2
3. Laboratory of Immunology and Vascular Biology (L.A.Z., E.C.B.), Department of Pathology, Stanford University School of Medicine, Stanford, California 94305
4. Palo Alto Institute for Research and Education (B.A.Z.), Palo Alto, California 94304
5. Veterans Affairs Hospital, and Center for Molecular Biology and Medicine (B.A.Z., E.C.B.), Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304