Development of super Vδ2 T cells for relapsed/refractory acute myeloid Leukemia via non-viral site-specific integration.

The efficacy of chimeric antigen receptor (CAR)-T cell therapy in relapsed/refractory acute myeloid leukemia (R/R AML) is limited by tumor heterogeneity, antigen evasion, and treatment-related toxicities. Gamma delta (γδ) T cells mediate antitumor activity independent of MHC by sensing stress-induced ligands. A prominent mechanism involves NKG2D ligand (NKG2DL) recognition, which is highly upregulated in malignancies but generally low or restricted expression in healthy tissues under homeostatic conditions. In human peripheral blood, the Vδ2 subset represents the predominant population. Vδ2 T cells transduced with the NKG2D-CD3ζ construct, which incorporates into the natural γδ TCR/CD3 complex, preserve innate phosphoantigen recognition while acquiring potent NKG2DL-directed cytotoxicity, enabling dual-pathway tumor recognition. These cells are termed "Super Vδ2 T cells." We successfully generated TRAC-specific integrated Super Vδ2 T cells using CRISPR/Cas9 technology, achieving 90-93% CAR+ expression. In vitro assays demonstrated that the engineered "Super Vδ2 T cells" exhibited potent cytotoxic activity against multiple AML targets, including cell lines and primary R/R AML blasts, in contrast to their negligible toxicity on monocytes. In vivo, Super Vδ2 T cells demonstrated substantial tumor reduction without graft-versus-host disease (GvHD) reaction. Collectively, our data demonstrated that Super Vδ2 T cells represent a viable allogeneic therapy for AML.