1. From the Institute for Biomedical Aging Research (H.P., M.M., G.M., Q.X., G.W.), Austrian Academy of Sciences, Innsbruck, and the Institute of Pathophysiology (H.P., C.M., G.W.), University of Innsbruck Medical School, Innsbruck, Austria; the Institute of Infectious Diseases and Immunology (R.v.d.Z.), Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands; and the Department of Microbiology (S.G.M., R.P.M.), Montana State University, Bozeman, Mont.