This area includes the development of methods for the stimulation or suppression of the immune system. One key topic is improving the smooth acceptance of transplants by inducing specific tolerance. Fraunhofer IZI develops diagnostic methods to monitor immunoreactivity and to monitor unwanted responses such as GVHD (graft versus host disease). It also develops vaccines on an innovative technology platform for the inactivation of pathogens, method which is particularly safe, robust and inexpensive.