Enhancing specific thymic Treg activation and function with 4-1BB monomeric streptavidin-based CARs

Area of Science:

• Immunology
• Cell Therapy
• Translational Medicine

Background:

• Hyperinflammatory diseases involve excessive immune activation and tissue damage.
• Regulatory T (Treg) cells are crucial for immune homeostasis but can be impaired in disease.
• Current immunosuppressive therapies have limitations and adverse effects.

Purpose of the Study:

• To engineer universal chimeric antigen receptor Tregs (UniCAR-Tregs) for treating inflammatory disorders.
• To evaluate the efficacy of UniCAR-Tregs in a preclinical graft-versus-host disease (GvHD) model.
• To assess the impact of different CAR constructs on Treg function and phenotype.

Main Methods:

• Lentiviral transduction of human thymus-derived Tregs (thyTregs) with second- and third-generation UniCAR constructs.
• Characterization of engineered thyTreg phenotype and transcriptomic profile.
• In vitro assessment of suppressive capacity using mixed lymphocyte reaction and in vivo evaluation in a GvHD mouse model.

Main Results:

• UniCAR constructs were successfully introduced into thyTregs without compromising their regulatory phenotype.
• The UniCAR41BB construct specifically activated thyTregs and enhanced their suppressive function.
• In vivo, UniCAR41BB thyTregs delayed GvHD onset and improved survival in mice.

Conclusions:

• Human thyTregs can be effectively engineered with UniCAR constructs.
• The second-generation UniCAR41BB construct demonstrates enhanced antigen-dependent suppressive function.
• UniCAR41BB thyTregs represent a promising therapeutic platform for GvHD and other inflammatory disorders.