在 CXCL12 与 NOTCH 配体存在下静息使效应/耗竭 CAR-T 细胞年轻化为干细胞记忆样 CAR-T 细胞

UNLABELLED: T cells with a stem cell memory (T SCM ) phenotype provide long-term and potent antitumor effects for T-cell transfer therapies. Although various methods for the induction of T SCM -like cells in vitro have been reported, few methods generate T SCM -like cells from effector/exhausted T cells.

We have reported that coculture with the Notch ligand-expressing OP9 stromal cells induces T SCM -like (iT SCM ) cells.

Here, we established a feeder-free culture system to improve iT SCM cell generation from expanded chimeric antigen receptor (CAR)-expressing T cells; culturing CAR T cells in the presence of IL7, CXCL12, IGF-I, and the Notch ligand, hDLL1.

Feeder-free CAR-iT SCM cells showed the expression of cell surface markers and genes similar to that of OP9-hDLL1 feeder cell-induced CAR-iT SCM cells, including the elevated expression of SCM-associated genes, TCF7 , LEF1 , and BCL6 , and reduced expression of exhaustion-associated genes like LAG3 , TOX , and NR4A1 . Feeder-free CAR-iT SCM cells showed higher proliferative capacity depending on oxidative phosphorylation and exhibited higher IL2 production and stronger antitumor activity in vivo than feeder cell-induced CAR-iT SCM cells.

Our feeder-free culture system represents a way to rejuvenate effector/exhausted CAR T cells to SCM-like CAR T cells. SIGNIFICANCE: Resting CAR T cells with our defined factors reprograms exhausted state to SCM-like state and enables development of improved CAR T-cell therapy.