But what exactly are iPS cells? These cells can be developed from other adult cell types, like skin or blood cells, through genetic manipulation. An iPS cell can mature into any cell type, which makes them a powerful tool for biological research, and an excellent source of tissues for transplantation-based therapies. Further, iPS cells can be made specifically to the patient, which means that there’s a reduced risk of the patient rejecting them.
However according to senior author Neil Rodrigues, DPhil, iPS cells have been previously rejected in a study published in Nature in 2011. ‘The Nature study provocatively suggested that tissues derived from patient-specific iPS cells may be immunogenic after transplantation. However, it never directly assessed the immunogenicity of the therapeutically relevant cell types that could be utilized in regenerative medicine and transplantation,’ says Rodrigues, who alongside co-author Ashleigh Boyd, DPhil, is an assistant professor of dermatology at BUSM, researcher at the Centre for Regenerative Medicine (CReM) at Boston University and Boston Medical Centre (BMC), and lead investigator at the National Institutes of Health’s Canter of Biomedical Research Excellence (COBRE).
Therefore, the team took adult cells from an experimental model and derived iPS cells from them, to evaluate this matter. They then differentiated the cells into three cell types, neuronal (nerve); hepatocytes (liver); and endothelial (blood vessel lining) cells, and transplanted them into a genetically identical experimental model. They found no signs of an elevated immune response or rejection. This suggests that doctors could avoid using immunosuppressive drugs to treat immune rejection in transplantation, as these drugs can lead to serious side-effects, including developing cancer.
Boyd concluded, ‘If the use of immunosuppressive drugs can be avoided, as may be the case for patient-specific iPS cell based therapies, it would be preferable. Our results are very promising and future work should be directed at assessing whether tissues derived from human iPS cells will similarly lack immunogenicity.’