Abstract
Human kidney organoids derived from embryonic stem cells (ESCs) or induced pluripotent stem cells (iPSCs) have become novel tools for studying various kidney pathologies. Here, we transplanted ESC-derived kidney organoids into humanized mice with a mature human adaptive immune system developed through thymic education. As judged by histology and immunophenotyping, the transplanted HLA-mismatched kidney organoids trigged a robust alloimmune response, characterized by a dense immune cell infiltrate and enhanced memory T cell phenotype in the allograft 30 days post-transplantation. Multiplexed immunofluorescence revealed expression of functional markers of various immune cell infiltrates in response to organoid allografts, mimicking the T cell-mediated rejection process in humans. This validated our model as a novel platform to study various therapeutic strategies to control alloimmunity. Splenocytes isolated from organoid-transplanted hosts showed an alloantigen-specific memory response against 2D kidney organoids ex vivo. Overall, our study indicates that transplanting kidney organoids in humanized mice may be a valuable tool for studying human allogeneic immunity.