Common Trajectories of Highly Effective CD19-Specific CAR T Cells Identified by Endogenous T-cell Receptor Lineages

Current chimeric antigen receptor-modifi ed (CAR) T-cell products are evaluated in bulk, without assessing functional heterogeneity. We therefore generated a com-prehensive single-cell gene expression and T-cell receptor (TCR) sequencing data set using pre-and postinfusion CD19-CAR T cells from blood and bone marrow samples of pediatric patients with B-cell acute lymphoblastic leukemia. We identifi ed cytotoxic postinfusion cells with identical TCRs to a sub-set of preinfusion CAR T cells. These effector precursor cells exhibited a unique transcriptional profi le compared with other preinfusion cells, corresponding to an unexpected surface phenotype (TIGIT +, CD62Llo, CD27-). Upon stimulation, these cells showed functional superiority and decreased expression of the exhaustion-associated transcription factor TOX. Collectively, these results demonstrate diverse effector potentials within preinfusion CAR T-cell products, which can be exploited for therapeutic applications. Furthermore, we provide an integrative experimental and analytic framework for elucidating the mechanisms underlying effector development in CAR T-cell products. SIGNIFICANCE: Utilizing clonal trajectories to defi ne transcriptional potential, we find a unique signa-ture of CAR T-cell effector precursors present in preinfusion cell products. Functional assessment of cells with this signature indicated early effector potential and resistance to exhaustion, consistent with postinfusion cellular patterns observed in patients. Superscript/Subscript Available更多