Human iPS cell-derived CD34+ hematopoietic progenitor cells induce T cell anergy in alloreactive CD8+ T cells (P2188)

Abstract

Abstract Human induced pluripotent stem (iPS) cells have emerged as an alternative source of pluripotent stem cells that can be used in regenerative medicine. However, knowledge about the immunological characteristics of their derivatives remains enigmatic. Here, human iPS cells were differentiated into CD34+ hematopoietic progenitor cells (HPCs).These iPS cell-derived HPCs poorly express MHC class-I antigens, and are MHC class-II negative. They also lack expression of costimulatory molecules CD80 and CD86, but show relatively high expression of PD-L1. To investigate whether these HPCs stimulate CTLs, we generated CD8+ T cells against HLA-A2. Subsequently, HPCs were used as target cells for the CTLs. Interestingly HPCs were not susceptible to alloreactive CTL killing in a cytotoxicity assay. HPCs also failed to trigger release of IL-2 by CTLs as a sign of their activation. This lack of CTL activation was partially due to low MHC class I expression by the HPCs because HPC cell lysis was partially restored after MHC class I upregulation by treatment with IFN-γ. Interestingly, the CTLs became anergic when incubated with HPCs. As expected, T cell anergy was abrogated by treatment with rIL-2. Collectively, anergy was a result of low expression of CD80 and CD86 and high expression of PD-L1. These data indicate for the first time that human iPS cell-derived CD34+ HPCs induce T cell anergy, a property that could be exploited for cellular allo-transplantation of iPS cell-derived tissues.