1. Department Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts 02118, Department of Chemistry, University of Natural Resources and Applied Life Sciences, Vienna, Austria, Department of Immunochemistry and Biochemical Microbiology, Leibniz Center for Medicine and Biosciences, D-23845 Borstel, Germany, and Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110