1. From the Department of Immunology (R.A.B.),Walter Reed Army Institute of Research, Silver Spring, Md; DeBakey Heart Center at Baylor College of Medicine and Methodist Hospital (Z.-M.D., E.M.D., L.H.M., C.M.B., A.R.B.), Houston, Tex; and the Department of Clinical Studies (T.K.P.), Central Laboratory, Royal Veterinary and Agricultural University, Copenhagen, Denmark.