1. From the Departments of Histochemistry (J.M.P.), Cardiology (C.S.R.B., R.J.C.H.), and Infectious Diseases (T.J.E.), Imperial College School of Medicine, Hammersmith Hospital Campus and Heart Science Center (A.P., M.H.Y.), Imperial College School of Medicine, Harefield Hospital Campus, London, UK; and the Institut National de la Sante et de la Recherche Medicale (J.M.), Paris, and the C.E.A. (C.C.), Service de Pharmacolog et d’Immunologie, Saclay, France.