Armored human CAR T_reg cells with PD1 promoter-driven IL-10 have enhanced suppressive function

Area of Science:

• Immunology
• Cell Therapy
• Genetic Engineering

Background:

• Chimeric antigen receptor (CAR) technology has advanced regulatory T cell (Treg) therapy.
• Human Treg cells have limited IL-10 production and innate immune control compared to type 1 regulatory T cells (Tr1 cells).

Purpose of the Study:

• To engineer "hybrid" CAR Treg cells with Tr1 cell-like properties by modifying the PDCD1 locus.
• To enhance Treg cell function and IL-10 secretion for improved therapeutic potential.

Main Methods:

• Utilized CRISPR-mediated gene editing to delete PD1 in Treg cells.
• Performed knock-in of the IL10 gene under the PD1 promoter to achieve CAR-regulated IL-10 expression.
• Assessed Treg cell activation, IL-10 secretion, and suppressive function in vitro and in vivo.

Main Results:

• CRISPR-mediated PD1 deletion enhanced CAR Treg cell activation.
• IL10 knock-in enabled CAR-induced IL-10 secretion, improving Treg cell function.
• Engineered Treg cells demonstrated enhanced suppression of dendritic cells and antigen-specific T cells, and reduced graft-versus-host disease in vivo.

Conclusions:

• Simultaneously removing an inhibitory signal (PD1) and enhancing a suppressive mechanism (IL-10) is a novel strategy to improve CAR Treg cell potency.
• This CRISPR-mediated engineering approach creates stable, safe, and more potent CAR Treg cells for therapeutic applications.