1 Max von Pettenkofer Institute & Gene Center, Virology, Faculty of Medicine, LMU München, Munich, 81377, Germany.
2 Research Unit Lung Repair and Regeneration, Comprehensive Pneumology Center, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Member of the German Center of Lung Research (DZL), Munich, Germany. h.adler@helmholtz-muenchen.de.