Solid organ transplantation is the method of choice for end-stage organ failure. However, despite progress in surgical techniques and immunosuppression, long-term survival of allografts is still a major goal in transplantation medicine. Moreover, the increasing demand for organ transplantation and the shortage of available organs limit the success of transplantation programs. Consequently, acceptance of expanded criteria donor (ECD) organs with the increasing risk of unfavorable outcome has become an increasing reality. This necessitates the need for alternative strategies to treat the donor organ in order to prolong allograft survival. Our research is dedicated to understanding the immune response leading to rejection or tolerance of solid transplants in more detail. We therefore focus on various risk factors impacting the outcome of transplanted organs including donor brain death, donor and recipient age, ischemia-reperfusion injury and the influence of immunosuppression in experimental and translational projects. Our aim is to generate a comprehensive knowledge about the various immunological facets in organ transplantation finally leading to novel and innovative therapeutic treatment alternatives.