CORE C - SUMMARY/ABSTRACT Our multi-disciplinary team includes the expertise of transplant immunologists with a focus on T and B cell immunity, aging, cellular senescence and immunosenescence. Microsurgical procedures need to be kept on an expert, high level to assure reproducibility. Animal care, and surgical training are therefore a prerequisite for reliable experimental readouts. Transplants in older animals come with additional challenges as those animals are more sensitive to blood loss, length of surgery, and anesthesia. Current and ongoing expertise in microsurgery will therefore be essential for the success of our project. The overall goals of this core are: 1.) to perform transplant surgeries for all projects under this PPG; 2.) to coordinate experiments among projects and maximize the use of biological samples; 3.) to store and archive extra human/mouse biological samples; 4.) to provide support for additional interventions including recurrent blood collection, intravenous infusions of antibodies, drugs, and FRC; 5.) to provide training to microsurgeons ensuring consistent technical skills even during changes in personnel; 6.), to supervise all regulatory aspects including Institutional Review Board compliance in addition to coordinating data and specimen acquisition and analysis by the different projects in this proposal.