Details

Autor(en) / Beteiligte

• Funk, Maximilian A.
• Heller, Gerwin
• Waidhofer-Söllner, Petra
• Leitner, Judith
• Steinberger, Peter

Titel

Inhibitory CARs fail to protect from immediate T cell cytotoxicity

Ist Teil von

• Molecular therapy, 2024-04, Vol.32 (4), p.982-999

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2024

Quelle

MEDLINE

Beschreibungen/Notizen

• Chimeric antigen receptors (CARs) equipped with an inhibitory signaling domain (iCARs) have been proposed as strategy to increase on-tumor specificity of CAR-T cell therapies. iCARs inhibit T cell activation upon antigen recognition and thereby program a Boolean NOT gate within the CAR-T cell. If cancer cells do not express the iCAR target antigen while it is highly expressed on healthy tissue, CAR/iCAR coexpressing T cells are supposed to kill cancer cells but not healthy cells expressing the CAR antigen. In this study, we employed a well-established reporter cell system to demonstrate high potency of iCAR constructs harboring BTLA-derived signaling domains. We then created CAR/iCAR combinations for the clinically relevant antigen pairs B7-H3/CD45 and CD123/CD19 and show potent reporter cell suppression by iCARs targeting CD45 or CD19. In primary human T cells αCD19-iCARs were capable of suppressing T cell proliferation and cytokine production. Surprisingly, the iCAR failed to veto immediate CAR-mediated cytotoxicity. Likewise, T cells overexpressing PD-1 or BTLA did not show impaired cytotoxicity toward ligand-expressing target cells, indicating that inhibitory signaling by these receptors does not mediate protection against cytotoxicity by CAR-T cells. Future approaches employing iCAR-equipped CAR-T cells for cancer therapy should therefore monitor off-tumor reactivity and potential CAR/iCAR-T cell dysfunction. [Display omitted] Steinberger and colleagues dissect mechanisms of inhibitory CARs that should reduce on-target off-tumor toxicity in CAR-T cells. Improved iCAR constructs for clinically relevant on-target off-tumor toxicity problems were created. While iCARs effectively suppressed transcriptionally dependent effector functions in reporter cells and primary CAR-T cells, direct cytotoxicity was not affected.