CAR signaling instructs divergent metabolic reprogramming and functional fates in αβ and γδ T cells

Abstract γδ T-cell-based immunotherapies have become relevant as alternatives to conventional αβ T-cell products, with preclinical data demonstrating tumor burden reduction and the mitigation of tumor-induced tissue damage. Given that most CAR constructs have been optimized for αβ T cells, we hypothesized that distinct T-cell types may require tailored CAR architectures to achieve optimal function. To test this hypothesis, we conducted a systematic comparative analysis of γδ and αβ T cells transduced with a second-generation PSCA-targeting CAR (PSCA-8t28z). We found that although γδ and αβ CAR-T cells exhibit comparable levels of cytotoxicity, they differ phenotypically. Through a system-level phosphoproteomic analysis, we identified 307 phosphosites whose abundance differed between γδ and αβ CAR-T cells. Pathway enrichment analysis placed glycolysis/gluconeogenesis and TCR signaling within the top significantly overrepresented signaling networks. The results of functional validation studies confirmed that γδ CAR-T cells have lower glycolytic and oxidative phosphorylation capacity than αβ-CAR-T cells do and weaker activation of activator protein 1 (AP-1). Notably, we identified thioredoxin-interacting protein (TXNIP) as a potential actionable target to enhance γδ CAR-T-cell metabolism. Finally, we designed a new synthetic costimulatory receptor that potentiates AP-1 activation, resulting in improved in vivo persistence. These results highlight the fundamental biological differences between γδ and αβ T cells and support the development of cell type-specific receptor engineering strategies to maximize γδ CAR-T-cell function and therapeutic benefit.