Abstract
Antigen-independent tonic signaling by chimeric antigen receptors (CARs) can increase differentiation and exhaustion of T cells, limiting their potency. Incorporating 4-1BB costimulation in CARs may enable T cells to resist this functional exhaustion; however, the potential ramifications of tonic 4-1BB signaling in CAR T cells remain unclear. Here, we found that tonic CAR-derived 4-1BB signaling can produce toxicity in T cells via continuous TRAF2-dependent activation of the nuclear factor κB (NF-κB) pathway and augmented FAS-dependent cell death. This mechanism was amplified in a non-self-inactivating gammaretroviral vector through positive feedback on the long terminal repeat (LTR) promoter, further enhancing CAR expression and tonic signaling. Attenuating CAR expression by substitution with a self-inactivating lentiviral vector minimized tonic signaling and improved T cell expansion and anti-tumor function. These studies illuminate the interaction between tonic CAR signaling and the chosen expression platform and identify inhibitory properties of the 4-1BB costimulatory domain that have direct implications for rational CAR design. Gomes-Silva et al. model tonic signaling from chimeric antigen receptors (CARs) harboring the 4-1BB endodomain and describe a mechanism through which this signaling produces toxicity in T cells. CAR-driven tonic 4-1BB signaling activates the LTR promoter in gammaretroviral vectors, thus further amplifying the toxicity and undermining CAR T cell anti-tumor activity.
Original language | English (US) |
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Pages (from-to) | 17-26 |
Number of pages | 10 |
Journal | Cell Reports |
Volume | 21 |
Issue number | 1 |
DOIs | |
State | Published - Oct 3 2017 |
Keywords
- 4-1BB
- T cells
- adoptive T cell therapy
- chimeric antigen receptor
- costimulation
ASJC Scopus subject areas
- General Biochemistry, Genetics and Molecular Biology