Over the years, manipulation of the immune system has become a promising therapeutic approach. In particular, chimeric antigen receptor expressing T cells (CAR T cells) represent a breakthrough for cancer treatment, having already proved efficacy in B cell malignancies. However, the vast majority of the current CAR T cell products are based on autologous T cells, which increases the cost and reduces the efficacy of the therapy. Additionally, some of the adverse effects of this therapy are related to the phenotype of the infused cells.

To address these limitations, we have generated universal antiCD19 CAR T cells with a defined memory phenotype. By elimination of B2M and TRAC genes in CAR T cells we aim to avoid both graft versus host and host versus graft reactions in the patient. We have also selected the less differentiated T cells to obtain more stable and persistent universal CAR T cells. Different safety analyses were additionally carried on to ensure the safety of our editing strategy.

Our in vitro data demonstrate that we can generate functional universal CAR T cells. The elimination of TCR and HLA-I from the surface of CAR T cells reduces the bidirectional allogeneic response between cells from different donors. This edition persists over time and does not affect neither phenotype of cells nor CAR expression. Universal CAR T cells with a memory phenotype proved to be equally lytic as bulk CD19-CAR T cells.