Divergent cytotoxic and inflammatory functions of intratumoral Vδ2+ γδ T cells in renal cell carcinoma.

Vγ9Vδ2 T cells are blood-circulating, innate-like lymphocytes that contribute to tumor immunosurveillance and constitute over 95% of Vδ2+ γδ T cells, but how they perform antitumor or protumor functions remains unclear. Here, we comprehensively characterized Vδ2+ γδ T cells in paired peripheral blood and tumor samples from patients with renal cell carcinoma using flow cytometry and single-cell transcriptomic analysis. We identified two major Vδ2+ γδ T cell subsets distinguished by expression of CD16, which were present at variable proportions in both circulation and tumors. Notably, the proportion of CD16+Vδ2+ γδ T cells in blood closely reflected those in matched tumor tissues. Functionally, CD16+Vδ2+ γδ T cells exhibited potent cytotoxic capacity, characterized by high granzyme B expression and enhanced degranulation upon activation. In contrast, CD16-Vδ2+ γδ T cells displayed central and effector memory features, expressed higher levels of CCR5, CXCR3, and granzyme K, and showed superior migratory capacity but limited cytotoxic activity. Single-cell RNA sequencing of tumor-infiltrating Vδ2+ γδ T cells identified four transcriptional clusters, including FCGR3A + cytotoxic and GZMK + inflammatory clusters corresponding to CD16+ and CD16- subsets, respectively. A TOX + cluster exhibited progenitor-like features, giving rise to two divergent effector states along a differentiation trajectory. Within tumors, both CD16+ and CD16- γδ T cells were broadly distributed and CD16+ γδ T cells were more preferentially co-localized with tumor cells than CD16- γδ T cells. Collectively, these findings demonstrate that blood and intratumoral Vδ2+ γδ T cells are functionally heterogeneous and segregate into cytotoxic and inflammatory effector programs.