CD69+ Vδ1γδ T cells are anti-tumor subpopulations in hepatocellular carcinoma

Background & aims: Hepatocellular carcinoma (HCC), one of the malignancies with a wide expression of stress ligands recognized by V delta 1 gamma delta T cells, has received much attention in adoptive immunotherapy of gamma delta T cells. In this study, we aimed to identify the potential anti-tumor V delta 1 gamma delta T subpopulations in HCC. Methods: Healthy donors (HDs) and HCC patients were recruited from the Affiliated Cancer Hospital of Zhengzhou University. Blood and tumor tissue samples were obtained respectively. Bioinformatics methods were used to analyze total gamma delta T cells and subsets infiltration, overall survival of HCC patients with high and low infiltration level of V delta 1 gamma delta T cells, and IFNG, granzyme A, granzyme B and perforin expression in TRDV1high/lowCD69high/low groups. CD69 expression and V delta 1 gamma delta T cells infiltration in HCC were detected by immunofluorescence. Phenotypic analysis of V delta 1 gamma delta T cells in blood and tumor tissue samples were performed by flow cytometry. Results: V delta 1 gamma delta T cells infiltrating in HCC were associated with better clinical outcome. Study in tumor microenvironment (TME) of HCC demonstrated that not total V delta 1 gamma delta T but CD69+ V delta 1 gamma delta subset infiltration was associated with smaller tumor volume. Moreover, HCC patients simultaneously with high TRDV1 and CD69 expression produced more effector molecules and had longer survival time. Since V delta 1 gamma delta T cells in the tumor microenvironment were often difficult to access, we demonstrated that CD69+ V delta 1 gamma delta T cells also existed in peripheral blood mononuclear cells (PBMC) of HCC and displayed enhanced cytotoxic potentials than HDs. Finally, we investigated the functions and found that CD69+ V delta 1 gamma delta T cells exhibited stronger tumor reactivities when challenged by tumor cells. Conclusions: CD69+ V delta 1 gamma delta T cells are functional V delta 1 gamma delta T cell subsets in patients with HCC. Circulating CD69+ V delta 1 gamma delta T cell is a promising candidate in immunotherapy of HCC.