Advancements in CAR T-Cell Therapy: Overcoming Antigen Escape and Immune Rejection with Dual-Antigen Targeting

The abstract discusses the development of an alternative strategy for treating progressive diseases post autologous CD19 CAR T treatment, which often occurs due to antigen escape. The proposed solution involves the use of allogeneic CAR T cells from healthy donors, which can be rapidly deployed. The study also suggests combining this with autologous CD22 CAR T therapeutics to potentially overcome antigen escape issues.

Researchers have developed a hypoimmune, allogeneic CAR T cell product by disrupting the TRAC gene to mitigate graft-versus-host disease (GvHD), disrupting B2M and CIITA genes to support immune evasion, and overexpressing CD47 to promote persistence and innate immune evasion. This approach is aimed at creating CAR T cell products with enhanced clinical durability.

The methodology involved engineering healthy donor T cells to evade innate immunity by transducing them with a lentivirus encoding CD47, attached to either CD19 or CD22 CAR to create dual-transduced CAR T cells overexpressing CD47. These cells were then subjected to in vitro and in vivo analysis against various leukemia and lymphoma cell lines. The efficiency of transduction was measured using flow cytometry and vector copy number (VCN), while cytotoxicity and cytokine production were assessed using IncuCyte and meso scale discovery analysis.

The study also involved creating hypoimmune versions of these CAR T cells by disrupting the B2M, CIITA, and TRAC genes using CRISPR-Cas12b technology. These hypoimmune CAR T cells were then analyzed in vitro and in vivo.

The results showed that the dual-transduced CAR T cells were efficient in controlling tumor growth in both in vitro and in vivo models. They also demonstrated a higher cytokine response compared to single CAR controls at low effector-to-target (E:T) ratios. The hypoimmune CAR T cells showed comparable cytotoxicity and cytokine responses to non-hypoimmune CAR T cells.

The study concludes that dual-transduced CD19 CAR x CD22 CAR T cells are effective in controlling antigen knockout models and may provide a universal CAR T cell solution that persists without immunosuppression while mitigating antigen escape. Ongoing research is evaluating how these hypoimmune CAR T cells evade adaptive and innate immune recognition.