[1] Univ Helsinki, Dept Bacteriol & Immunol, Haartman Inst, FIN-00014 Helsinki, Finland
[2] Univ Helsinki, Inst Biotechnol, FIN-00014 Helsinki, Finland
[3] Hans Knoell Inst, Jena, Germany
[4] Semmelweis Univ, Dept Internal Med 3, H-1085 Budapest, Hungary