Generation of TCR-negative CD8aß+ CAR T cells from T cell-derived induced pluripotent stem cells

The production of autologous T cells expressing a chimaeric antigen receptor (CAR) is time-consuming, costly and occasionally unsuccessful. T cell-derived induced pluripotent stem cells are a promising source for the generation of 'off-the-shelf' CAR T cells, but their in vitro differentiation often yields T cells with suboptimal features. Here we show that premature expression of the T cell receptor (TCR) or a constitutively expressed CAR promote the acquisition of an innate phenotype, which can be averted by disabling the TCR and relying on the CAR to drive T cell differentiation. Delaying CAR expression and calibrating its signalling strength enabled the generation of human CD8aß+ TCR– CAR+ T cells that perform overall similarly to peripheral blood CD8aß+ CAR+ T cells in achieving effective tumour control upon systemic administration in a mouse model of leukaemia, without causing graft-versus-host disease. Driving T cell maturation in the absence of a TCR by taking advantage of a CAR may facilitate the large-scale development of potent allogeneic CD8aß+ T cells for a broad range of immunotherapies. TRAC-1XX-iT cell generation: TiPS were differentiated to the DP T cell stage, and matured to CD8ab SP cells on 3T3-CD19-41BBL. CD8ab SP cells were purified by flow cytometry. Peripheral Blood Mononuclear cells were purified from healthy donor whole blood. CD4 and CD8 T cells were targeted with CD19-28z-1XX CAR into the TRAC locus, NK and gdT cells were retrovirally transduced to express the CD19-28z-1XX CAR. Cells were purified for CAR expression by flow cytometry. Overall design: mRNA profiles of PBMC-derived ab-TCR CD8ab T cells, gd-TCR T cells, CD8ab TRAC-1XX-iT cells.