1. From the Neuroimmunology Branch (M.C.G.M., A.C., R.J.H., S.J.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD; The Wistar Institute (S.S.S., C.S., J.F.C., R.J.P., F.L., T.E.M., P.M.L.), Philadelphia, PA; and Neuroimmunology Clinic (F.C.A., J.O.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD.