# CAR Signaling Informs Mechanisms to EnhanceMetabolism and Function in γδ T Cells

## TL;DR

This study explores how γδ T cells differ from αβ T cells when engineered with CARs, identifying ways to improve their function and metabolism for better cancer therapies.

## Contribution

The study reveals cell-type-specific CAR design requirements and identifies a new synthetic receptor to enhance γδ CAR-T cell performance.

## Key findings

- γδ and αβ CAR-T cells show similar cytotoxicity but distinct metabolic and signaling profiles.
- γδ CAR-T cells have reduced glycolytic and oxidative phosphorylation capacity compared to αβ CAR-T cells.
- A synthetic co-stimulatory receptor improves AP-1 activation and in-vivo persistence of γδ CAR-T cells.

## Abstract

γδ T cell-based immunotherapies have gained relevance as an alternative to the conventional αβ T cell products with pre-clinical data demonstrating tumor burden reduction and mitigation of tumor-induced damage. Given that most CAR constructs were 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 between 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 cytotoxicity, they differ phenotypically. Through a system level phosphoproteomic analysis, we identified 307 phospho-sites with differential abundance between γδ and αβ CAR-T cells. Pathway enrichment analysis placed glycolysis/gluconeogenesis and TCR signaling within the top significantly overrepresented signaling networks. Functional validation studies confirmed that γδ CAR-T cells show lower glycolytic and oxidative phosphorylation capacity than αβ, and weaker Activator Protein 1 (AP-1) activation. Notably, we identified Thioredoxin-Interacting Protein as a potential actionable target to enhance γδ CAR-T cell metabolism. Finally, we designed a new synthetic co-stimulatory receptor that potentiates AP-1 activation resulting in improved in-vivo persistence. These results highlight 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.