CAR T-cells dysfunction in the central nervous system is mediated by BBB-induced activation-induced cell death

Aharony Tevet, Y.; Ravid, O.; Yanir, A. D.; Meir, A.; Levi, H.; Burstein, D.; Amram, A.; Feuerstein, T.; Izraeli, S.; Cooper, I.; Jacoby, E.

doi:10.1101/2025.10.21.683607

bioRxiv · 10.1101/2025.10.21.683607

CAR T-cells dysfunction in the central nervous system is mediated by BBB-induced activation-induced cell death

Aharony Tevet, Y.·Ravid, O.·Yanir, A. D.·Meir, A.·Levi, H.·Burstein, D.·Amram, A.·Feuerstein, T.·Izraeli, S.·Cooper, I.·Jacoby, E.

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Abstract

Chimeric Antigen Receptor (CAR) T-cells can eliminate leukemia and lymphoma within the central nervous system (CNS). Following a case with CD19+ relapse in the CNS in the presence of persisting Tisagenlecleucel, we generated several models to study CAR T-cells in the CNS. In both immunocompetent and humanized leukemia-bearing mice, CNS-residing CAR T-cells were shown to have inferior ex-vivo killing capacities compared to CAR T-cells harvested from the spleen or bone marrow of receptive mice. In a mechanistic work-up, we identified two contributing factors: First, CAR T-cells cultured in cerebrospinal fluid showed impaired cytotoxic and proliferative function compared to those in serum or other media. Second, using a unique in vitro human blood-brain barrier (BBB) model composed of endothelial cells and brain pericytes, we demonstrated that CAR T-cells that crossed the BBB exhibited antigen-independent activation and diminished cytolytic capacity. This led to increased activation-induced cell death of the BBB-migrating CAR T-cells and was confirmed to be independent of the CAR target and the costimulatory domain. Our findings add possible mechanisms of CAR T-cell resistance in the CNS, relevant for CNS hematologic and non-hematologic tumors.

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Aharony Tevet, Y., Ravid, O., Yanir, A. D., Meir, A., Levi, H., Burstein, D., Amram, A., Feuerstein, T., Izraeli, S., Cooper, I., Jacoby, E.. 2025-10-21. CAR T-cells dysfunction in the central nervous system is mediated by BBB-induced activation-induced cell death. https://doi.org/10.1101/2025.10.21.683607

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