引入 4-1BB 共刺激增强靶向 IL13Rα2 的 CAR-T 细胞的选择性和功能性

UNLABELLED: Chimeric antigen receptor (CAR) T cell immunotherapy is emerging as a powerful strategy for cancer therapy; however, an important safety consideration is the potential for off-tumor recognition of normal tissue. This is particularly important as ligand-based CARs are optimized for clinical translation.

Our group has developed and clinically translated an IL13(E12Y) ligand-based CAR targeting the cancer antigen IL13R 2 for treatment of glioblastoma (GBM). There remains limited understanding of how IL13-ligand CAR design impacts the activity and selectivity for the intended tumor-associated target IL13R 2 versus the more ubiquitous unintended target IL13R 1. In this study, we functionally compared IL13(E12Y)-CARs incorporating different intracellular signaling domains, including first-generation CD3 -containing CARs (IL13 ), second-generation 4-1BB (CD137)-containing or CD28-containing CARs (IL13-BB or IL13-28 ), and third-generation CARs containing both 4-1BB and CD28 (IL13-28BB ).

In vitro coculture assays at high tumor burden establish that second-generation IL13-BB or IL13-28 outperform first-generation IL13 and third-generation IL13-28BB CAR designs, with IL13-BB providing superior CAR proliferation and in vivo antitumor potency in human xenograft mouse models.

IL13-28 displayed a lower threshold for antigen recognition, resulting in higher off-target IL13R 1 reactivity both in vitro and in vivo . Syngeneic mouse models of GBM also demonstrate safety and antitumor potency of murine IL13-BB CAR T cells delivered systemically after lymphodepletion.

These findings support the use of IL13-BB CARs for greater selective recognition of IL13R 2 over IL13R 1, higher proliferative potential, and superior antitumor responsiveness.

This study exemplifies the potential of modulating factors outside the antigen targeting domain of a CAR to improve selective tumor recognition. SIGNIFICANCE: This study reveals how modulating CAR design outside the antigen targeting domain improves selective tumor recognition. Specifically, this work shows improved specificity, persistence, and efficacy of 4-1BB-based IL13-ligand CARs. Human clinical trials evaluating IL13-41BB-CAR T cells are ongoing, supporting the clinical significance of these findings.