CAR Density Influences Antitumoral Efficacy of BCMA CAR T Cells and Correlates with Clinical Outcome [ATAC-seq]

In this work, we address the impact of CAR density on the in vitro and in vivo functionality of BCMA-CAR T cells. Phenotypic, functional, transcriptomic and epigenomic studies at bulk and single cell level revealed different profiles between CAR T cells with high and low expression of the CAR molecule (CARHigh and CARLow T cells). We analyzed the phenotype of CARHigh and CARLow T cell populations before and after stimulation with tumor cells. Sorted CD4+ and CD8+ CARHigh and CARLow T cell populations from six different CAR T cell productions were profiled using high-throughput RNA sequencing (RNA-seq) and assay for transposase-accessible chromatin (ATAC-seq). To better understand the heterogeneity of CAR T cells and the influence of CAR level on their transcriptomic profile, we performed single cell transcriptomic analysis on 43,981 CAR T cells from three independent productions. Overall design: We have carried out a comprehensive study of the influence of CAR density in CAR T cell function. We have performed ATAC-seq of CAR T cells.