The invention relates to a protection device for ventilation ducts where at least one duct opening for the supply andor evacuation of air is provided, in particular for fire protection of air conditioned rooms for information technology installations. In particular, the invention discloses a releasable fastening system which has a pin with a locking cavity. The method of the invention also relates to broadening the resulting immune response by boosting with a protein-based vaccine. The requested class is then searched for in the classloader network.