1 Institute of Immunology, University Medicine Greifswald, F. Sauerbruchstr. DZ 7, 17475 Greifswald, Germany.
2 Institute of Immunology, University Medicine Greifswald, F. Sauerbruchstr. DZ 7, 17475 Greifswald, Germany. Electronic address: barbara.broeker@med.uni-greifswald.de.