Background: γδ T cells possess unique immunological features including tissue tropism, major histocompatibility complex-independent antigen recognition, and hybrid T/natural killer cell properties that make them promising candidates for cancer immunotherapy. However, the therapeutic potential of Vδ1 γδ T cells, particularly when engineered with chimeric antigen receptors (CARs), remains underexplored in solid tumors such as pancreatic cancer (PC), largely due to their low abundance in peripheral blood and challenges in ex vivo expansion. This study aims to directly compare the preclinical safety and efficacy among CAR-engineered Vδ1 γδ T cells, Vδ2 γδ T cells, and conventional αβ T cells.
Methods: We developed a CAR targeting prostate stem cell antigen (PSCA) and engineered it into human blood-derived Vδ1 γδ T cells. These PSCA CAR-Vδ1 T cells were evaluated for antitumor activity against PSCA-expressing pancreatic tumor cells using both in vitro cytotoxicity assays and in vivo xenograft mouse models. Comparative analyses were conducted using PSCA CAR-Vδ1 γδ T cells, PSCA CAR-Vδ2 γδ T cells, and PSCA CAR-αβ T cells. Safety assessments of these CAR-engineered T cell subsets were conducted to evaluate graft-versus-host disease (GvHD) and cytokine release syndrome (CRS), while exhaustion profiles were assessed using single-cell RNA sequencing.
Results: Our study demonstrated that PSCA CAR-Vδ1 γδ T cells, PSCA CAR-Vδ2 γδ T cells, and PSCA CAR-αβ T cells exhibited similar antitumor efficacy. However, PSCA CAR-Vδ1 T cells did not exhibit GvHD or CRS compared with CAR-αβ T cells. PSCA CAR-Vδ1 T cells also had lower scores for exhaustion when compared with PSCA CAR-Vδ2 T cells by single-cell transcriptomic analysis.
Conclusion: PSCA CAR-Vδ1 γδ T cells represent a potent and safe therapeutic modality for PSCA+ PC, with efficacy comparable to other CAR T cell types and potential advantages in safety and persistence. These findings support further development of CAR-Vδ1 T cell immunotherapy for solid tumors.
Keywords: Adoptive cell therapy - ACT; Chimeric antigen receptor - CAR; Immunotherapy; Solid tumor; T cell.
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