Immunogenicity of Induced Pluripotent Stem Cells

Abstract

### Immunogenicity of Induced Pluripotent Stem Cells Zhao et al Nature . 2011. doi:10.1038/nature10135 A new study shows the immunogenicity of induced pluripotent stem cells by the direct transplantation of undifferentiated cells into syngenic mice. The reprogramming of somatic cells into pluripotent stem cells has been reported after introducing a combination of several defined factors, such as OCT3/4, SOX2, KLF4, and c-MYC, into the cells.1 These artificially established cells are termed induced pluripotent stem cells (iPSCs). The iPSCs show unlimited growth while maintaining their potential for differentiation into various cell types of all 3 germ layers. Their pluripotency has been clearly shown by their contribution to chimeric animals and by the development of a full-term mouse during a tetraploid complementation experiment. These data also indicated that cells differentiated from iPSCs can at least partially replace the biological functions of various organs. Unlike embryonic stem cells (ESCs), iPSCs can be generated from a patient's own somatic cells. Therefore, the potential utility of iPSCs for regenerative medicine has been suggested. The development of iPSC-derived differentiated cells has been expected to provide personalized cells for cell-based therapy. However, the immunogenicity of these cells had not yet been strictly examined. Recently, Zhao et al. reported that the transplantation of immature iPSCs induced a T-cell–dependent immune response even in a syngenic mouse.2 When injected into immunodeficient mice, undifferentiated pluripotent cells grow locally, differentiate, and form teratomas that contain various cell types, including neurons, cartilage, keratinocytes, and intestinal epithelium. In this study, the authors investigated the immunoreactions …