1. From the Departments of Medicine (K.A.W., A.L.C., M.Y., G.S., R.M.L, J.N, D.K.V., J.A.B.), Pathology (K.A.W., M.Y., R.M.L, J.A.B.), and Microbiology and Immunology (S.R.K., R.L.M), University of California, Los Angeles; and the Department of Physiology (E.J.S.), University of Kentucky Medical School, Lexington.