Vγ9Vδ2 T Cells Concurrently Kill Cancer Cells and Cross-Present Tumor Antigens

Abstract

The human Vγ9Vδ2 T cell is a unique cell type that holds great potential in immunotherapy of cancer. In particular, the therapeutic potential of this cell type in adoptive cell therapy (ACT) has gained interest. In this regard optimization of in vitro expansion methods and functional characterization is desirable. We show that Vγ9Vδ2 T cells, expanded in vitro with zoledronic acid (Zometa or ZOL) and Interleukin-2 (IL-2), are efficient cancer cell killers with a trend towards increased killing efficacy after prolonged expansion time. Thus, Vγ9Vδ2 T cells expanded for 25 days in vitro killed prostate cancer cells more efficiently than Vγ9Vδ2 T cells expanded for 9 days. These data are supported by phenotype characteristics, showing increased expression of CD56 and NKG2D over time, reaching above 90% positive cells after 25 days of expansion. At the early stage of expansion, we demonstrate that Vγ9Vδ2 T cells are capable of cross-presenting tumor antigens. In this regard, our data show that Vγ9Vδ2 T cells can take up tumor-associated antigens (TAA) gp100, MART-1 and MAGE-A3 - either as long peptide or recombinant protein – and then present TAA-derived peptides on the cell surface in the context of HLA class I molecules, demonstrated by their recognition as targets by peptide-specific CD8 T cells. Importantly, we show that cross-presentation is impaired by the proteasome inhibitor lactacystin. In conclusion, our data indicate that Vγ9Vδ2 T cells are broadly tumor-specific killers with the additional ability to cross-present MHC class I-restricted peptides, thereby inducing or supporting tumor-specific αβTCR CD8 T cell responses. The dual functionality is dynamic during in vitro expansion, yet, both functions are of interest to explore in ACT for cancer therapy.

The Diverse Roles of γδ T Cells in Cancer: From Rapid Immunity to Aggressive Lymphoma

“…Functionally, γδ T cells can be rapidly activated by specific receptor–ligand interactions [ 7 ], upon which they possess the capacity for clonal expansion and provide a major source of cytokine and chemokine production [ 18 , 19 , 20 , 21 ]. This facilitates their abilities to exert direct or indirect immune responses by functioning as professional antigen presenting cells (APCs) [ 22 , 23 ], providing T- and B-cell helper functions [ 24 ] or directly killing compromised cells [ 25 , 26 , 27 ]. Importantly, γδ T cells can rapidly respond to specific ligand types that are not recognised by other immune cells, where stress signal recognition by γδ T cells as one example in particular is critical for the immune detection of many cancers [ 28 , 29 ].…”

γδ T Cell–Based Adoptive Cell Therapies Against Solid Epithelial Tumors

“…Cells obtained with IL-2/Zol increase the expression of NK markers NKG2D and CD56 over time, an effect accompanied with greater cytotoxic activity. 66 Contrastingly, costimulatory molecules such as CD80, CD86, and CCR7 are highly expressed during the initial expansion phase and decrease over culture time. 66 Thus, in vitro IL-2/Zol-expanded Vγ9Vδ2 T cells seem to shift from a costimulatory phenotype with high antigen cross-presentation capacity at early days into an effector phenotype over time.…”

“…75 Overall, markers such as CD69, HLA-DR, CD25, and NKactivating receptors such as DNAM-1 and NKG2D, as well as expression of immune checkpoints, are usually evaluated in ex vivo expanded γδ T cells to assess their phenotype. 28,66,67,76 However, there is a necessity to better characterize markers that define γδ Tcell populations with higher potency. Expansion of Vδ2 T cells with transforming growth factor β has been shown to upregulate CD103 expression, leading to a CD103 + population with the higher cytotoxic activity, especially against epithelium-derived tumor cells that express E-cadherin, the CD103 ligand.…”

Targeting Cytokine Signals to Enhance γδT Cell-Based Cancer Immunotherapy

“…It is also reported that human γδT-APCs efficiently cross-present soluble antigens to CD8 + T cells via MHC-I ( 50 , 51 ). The high expression levels of APC-associated molecules and tumor antigen presenting capability of in vitro expanded human Vγ9Vδ2 T cells were also detected during the early stage of differentiation ( 52 ). Activated human γδT cells boost NK cell mediated killing of tumor cells through CD137L ( 53 ).…”