Enhancing T Cell Receptor Stability in Rejuvenated iPSC-Derived T Cells Improves Their Use in Cancer Immunotherapy

Limited T cell availability and proliferative exhaustion present major barriers to successful T cell-based immunotherapies and may potentially be overcome through the use of “rejuvenated” induced pluripotent stem cells derived from antigen-specific T cells (T-iPSCs). However, strict antigen specificity is essential for safe and efficient T cell immunotherapy. Here, we report that CD8αβ T cells from human T-iPSCs lose their antigen specificity through additional rearrangement of the T cell receptor (TCR) α chain gene during the CD4/CD8 double positive stage of in vitro differentiation. CRISPR knockout of a recombinase gene in the T-iPSCs prevented this additional TCR rearrangement. Moreover, when CD8αβ T cells were differentiated from monocyte-derived iPSCs that were transduced with an antigen-specific TCR, they showed monoclonal expression of the transduced TCR. TCR-stabilized, regenerated CD8αβ T cells effectively inhibit tumor growth in xenograft cancer models. These approaches could contribute to safe and effective regenerative T cell immunotherapies. [Display omitted] •Regenerated CD8αβ T cells lose antigen specificity by additional TRA rearrangement•Knockout of RAG2 in T-iPSCs completely blocks the unwanted TRA rearrangement•TCR-stabilized CD8αβ T cells are effectively induced from TCR transduced iPSCs•TCR-stabilized, regenerated CD8αβ T cells inhibit tumor growth in xenograft models Kaneko et al. describe the effective generation of antigen-specific T cell receptor-stabilized CD8αβ T cells from T cell-derived or monocyte-derived iPSCs, both with genetic modification at the iPSC stage. Those T cells showed monoclonal expression of desired TCR and effectively inhibited tumor growth in xenograft cancer models.