Engrafting human regulatory T cells with a flexible modular chimeric antigen receptor technology


Engrafting human regulatory T cells with a flexible modular chimeric antigen receptor technology

Koristka, S.; Kegler, A.; Bergmann, R.; Arndt, C.; Feldmann, A.; Albert, S.; Cartellieri, M.; Ehninger, A.; Ehninger, G.; Middeke, J. M.; Bornhäuser, M.; Schmitz, M.; Pietzsch, J.; Akgün, K.; Ziemssen, T.; Steinbach, J.; Bachmann, M. P.

As regulatory T cells (Tregs) play a fundamental role in immune homeostasis their adoptive transfer emerged as a promising treatment strategy for inflammation-related diseases. Preclinical animal models underline the superiority of antigen-specific Tregs compared to polyclonal cells. Here, we applied a modular chimeric antigen receptor (CAR) technology called UniCAR for generation of antigen-specific human Tregs. In contrast to conventional CARs, UniCAR-endowed Tregs are indirectly linked to their target cells via a separate targeting module (TM). Thus, transduced Tregs can be applied universally as their antigen-specificity is easily adjusted by TM exchange. Activation of UniCAR-engrafted Tregs occurred in strict dependence on the TM, facilitating a precise control over Treg activity. In order to augment efficacy and safety, different intracellular signaling domains were tested. Both 4-1BB (CD137) and CD28 costimulation induced strong suppressive function of genetically modified Tregs. However, in light of safety issues, UniCARs comprising a CD137-CD3z signaling domain emerged as constructs of choice for a clinical application of redirected Tregs. In that regard, Tregs isolated from patients suffering from autoimmune or inflammatory diseases were, for the first time, successfully engineered with UniCAR 137/z and efficiently suppressed patient-derived effector cells. Overall, the UniCAR platform represents a promising approach to improve Treg-based immunotherapies for tolerance induction.

Keywords: regulatory T cells; chimeric antigen receptor; immunotherapy; CD28; CD137 (4-1BB)

Permalink: https://www.hzdr.de/publications/Publ-26408
Publ.-Id: 26408