An international team of researchers led by scientists at the University of California San Diego School of Medicine, U.S., have reported of being able to successfully graft induced pluripotent stem cell (iPSC)-derived neural precursor cells back into the spinal cords of genetically identical adult pigs, avoiding the accompanying immunosuppression efforts. The grafted cells survived long term, displayed differentiated functionality and caused no tumours. So far, a major hurdle to using neural stem cells derived from genetically different donors to replace damaged or destroyed tissues, such as in a spinal cord injury, has been the persistent rejection of the introduced material (cells). This has necessitated the use of complex drugs and techniques to suppress the host’s immune response. The findings, which have been published in Science Translational Medicine , show that the same cells showed similar long-term survival in adult pigs with different genetic backgrounds after only short-course use of immunosuppressive treatment, once injected into the injured spinal cord.