Human Dendritic Cell-Derived Induced Pluripotent Stem Cell Lines Are Not Immunogenic.

Donor-specific induced pluripotent stem cells (iPSC) can be used to generate desired cell types, including naive immune effectors, for the treatment of different diseases. However, a greater understanding of the inherent immunogenicity of human iPSC and their cellular derivatives is needed for the development of safe and effective cell-replacement therapies, given that studies in mouse models claimed that the syngenic mouse iPSC lines can be immunogenic. We report the characterization of the innate and adaptive immune mechanisms in human iPSC lines derived from peripheral blood-derived dendritic cells using a nonintegrating RNA virus, Sendai virus. We show that these iPSC lines express mRNA of TLR molecules and the Ag-presentation pathway intermediates; however, these mRNA are not translated into functional proteins, and these iPSC lines do not induce TLR-mediated inflammatory cytokine responses or inflammasome activation. We also show that these iPSC lines do not activate T cells in an allogenic MLR; however, they express low levels of MHC class I molecules that can efficiently acquire antigenic peptides from their microenvironment and present them to Ag-specific T cells. In addition, we show that these iPSC lines can be efficiently differentiated into hematopoietic stem cell precursors, as well as APC, under appropriate culture conditions. Taken together, our data show that the dedifferentiation of human dendritic cells effectively shuts down their immunogenic pathways and implicates transcriptional and posttranscriptional mechanisms in this process.