1. Institute of Pharmacy and Food Chemistry, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany, Laboratory of Molecular Physiology, Universidad Central de Venezuela, Caracas, Venezuela, Institute of Medical Microbiology, Immunology and Parasitology, University of Bonn, Sigmund-Freud-Strasse 29, 53105 Bonn, Germany, FH-Bonn-Rhein-Sieg, Von-Liebig-Strasse 20, 53359 Rheinbach, Germany, and Heinrich-Pette-Institute for Experimental Virology and Immunology, Martinistrasse 52, 20251 Hamburg, Germany