Releasing the restraints of Vγ9Vδ2 T-cells in cancer immunotherapy
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ABSTRACT: Objectives: Vγ9Vδ2 T-cells are a subset of T-cells with a crucial role in immunosurveillance which can be activated and expanded by multiple means to stimulate effector responses. Little is known about the expression of checkpoint molecules on this cell population and whether the ligation of these molecules can regulate their activity. The aim of this study was to assess the expression of both activatory and inhibitory receptors on Vγ9Vδ2 T-cells to assess potential avenues of regulation to target with immunotherapy. Methods: Expression of various activatory and inhibitory receptors was assessed on Vγ9Vδ2 T-cells by flow cytometry following activation and expansion using zoledronic acid (ZA) and Bacillus Calmette-Guérin (BCG). Expression of these markers and production of effector molecules was also examined following co-culture with various tumour cell targets. The effect of immune checkpoint blockade on Vγ9Vδ2 T-cells was also explored. Results: Vγ9Vδ2 T-cells expressed high levels of activatory markers both at baseline and following stimulation. Vγ9Vδ2 T-cells expressed variable levels of inhibitory checkpoint receptors with many being upregulated following stimulation. Expression of these markers is further modulated upon co- culture with tumour cells with changes reflecting activation and effector functions. Despite their high expression of inhibitory receptors when cultured with tumour cells expressing cognate ligands there was no effect on Vδ2+ T-cell cytotoxic capacity or cytokine production with immune checkpoint blockade. Conclusions: Our work suggests the expression of checkpoint receptors present on Vγ9Vδ2 T-cells which may provide a mechanism with the potential to be utilised by tumour cells to subvert Vγ9Vδ2 T-cell cytotoxicity. This work suggests important candidates for blockade by ICI therapy in order to increase the successful use of Vγ9Vδ2 T-cells in immunotherapy.
Project description:Chronic lymphocytic leukaemia (B-CLL) is associated with immune suppression and functional impairment of NK cells, due partly to the reduced expression of activating receptors. We studied the profile of inhibitory checkpoint receptor expression on NK cells from patients with B-CLL. Single, dual and triple expression of the checkpoint receptors PD-1, CTLA-4, LAG-3 and CD96 was increased in patients compared to age-matched healthy controls. PD-1pos cells were present within the late differentiated CD56dim NK pool and showed strong downregulation of all activatory receptors whilst transcriptional profiles revealed a profile of strong receptor signalling. PD-1pos NK cells demonstrated impaired cytokine production and degranulation following target engagement and transfection of PD-1 into NK cell lines directed suppressed cytotoxic function. Importantly, blockade of PD-1:PD-L1 engagement acted to partially reverse these functional defects. These results reveal expression of inhibitory checkpoint receptors to be a new mechanism of NK cell dysfunction in patients with cancer and indicate a potential therapeutic role for single or combinatorial checkpoint blockade to boost immune function in patients with B-CLL.
Project description:CD8+ T cells are regulated by inhibitory and activatory receptors. We have investigated the influence of enforced CD27 stimulation compared with blockade of PD-1 and the combination of both agents together. Anti-CD27 and PD-1 blockade combined to enhance CD8+ T-cell accumulation, effector protein expression and tumor therapy. This array was used to further characterize the transcriptional changes in CD8+ T cells that drive this differentiation.
Project description:T-cell exhaustion occurs when T cells are chronically activated, usually in the context of cancer or chronic infection. Exhausted T cells lose effector functions, upregulate inhibitory receptors, and lose proliferation ability. Understanding the mechanisms of T-cell exhaustion is important as it has critical clinical applications, such as checkpoint blockade therapy. CD4+ T cells are understudied in the context of exhaustion, and no large-scale multiomic datasets containing proteomics, phosphoproteomics, or metabolomics exist. We therefor performed a multiomic experiment to profile this cell state using a time course analysis to also capture progression.
Project description:Cytotoxic T-lymphocyte associated antigen-4 (CTLA-4) and Programmed death-1 (PD-1) are immunoregulatory receptors expressed on T cells that play important roles in suppressing immune responses to cancer. Although monoclonal antibodies that target CTLA-4 or PD-1 stimulate therapeutic anti-tumour T cell responses, the tumour antigens recognized by checkpoint blockade immunotherapy remain undefined. Herein, we use genomics and bioinformatics approaches to identify tumour-specific mutant proteins as a major class of T cell rejection antigens following αPD-1 and/or αCTLA-4 treatment of mice bearing progressively growing sarcomas. We validate this conclusion by showing that (a) the predicted mutant epitopes associate with MHC class I molecules of the tumour; (b) T cells specific for these mutant epitopes infiltrate tumours; and (c) therapeutic vaccines incorporating these mutant epitopes induce tumour rejection comparably to checkpoint blockade immunotherapy. Whereas, T cells with the same antigen specificity are present in progressively growing tumours in control mice, tumour-specific T cells in αPD-1- and/or αCTLA-4-treated mice express some overlapping but mostly treatment-specific transcriptional profiles that render them capable of tumour rejection. Thus, tumour-specific mutant antigens are not only important targets of checkpoint blockade therapy but also can be used to identify tumour antigen-specific T cells that function as biomarkers of successful anti-tumour responses.
Project description:Checkpoint blockade with antibodies specific for the PD-1 and CTLA-4 inhibitory receptors can induce durable responses in a wide range of human cancers. However, the immunological mechanisms responsible for severe inflammatory side effects remain poorly understood. Here we report a comprehensive single cell analysis of immune cell populations in colitis, a common and severe side effect of checkpoint blockade. We observed strong enrichment of several T cell clusters in colitis lesions compared to control cases, in particular a striking accumulation of CD8 T cells with signatures reflecting highly cytotoxic and proliferative states. T cell receptor (TCR) sequence analysis demonstrated that a substantial fraction of colitis-associated CD8 T cells originated from tissue-resident populations, explaining the frequently early onset of colitis symptoms following treatment initiation. Our analysis also identified cytokines, chemokines and surface receptors that could serve as therapeutic targets for colitis and potentially other inflammatory side effects of checkpoint blockade.
Project description:CD19-targeting chimeric antigen receptor (CAR) T cell have become an important therapeutic option for patients with relapsed and refractory B cell malignancies. However, according to the recent clinical data, a significant portion of patients still do not benefit from the therapy, due various resistance mechanisms including the high expression of multiple inhibitory immune checkpoint receptors on activated CAR-T cells. Studies of checkpoint blockade immunotherapy using monoclonal antibodies have shown that simultaneously targeting inhibitory receptors that are functionally non-redundant can synergistically enhance anti-tumor responses. Here we report a lentiviral two-in-one CAR T approach in which two checkpoint receptors can be downregulated simultaneously by a dual short-hairpin RNA (shRNA) cassette integrated into a CAR vector. Using this system, we evaluated CD19-targeting CAR T cells in the context of four different checkpoint combinations, PD-1/TIM-3, PD-1/LAG-3, PD-1/CTLA-4, and PD-1/TIGIT, and found that the CAR T with PD-1/TIGIT downregulation uniquely exhibited synergistic anti-tumor effect in mouse xenograft models compared to the single PD-1 downregulation and maintained cytolytic and proliferative capacity upon repeated antigen exposure. Importantly, functional and phenotypic analysis of CAR T cells as well as analysis of transcriptomic profiles suggests that downregulation of PD-1 enhances short-term effector function while downregulation of TIGIT is primarily responsible for maintaining a less-differentiated/exhausted state, providing a potential mechanism of the synergy. The PD-1/TIGIT downregulated CAR T cells generated from DLBCL patient-derived T cells following clinically applicable manufacturing process also showed a robust anti-tumor activity and significantly improved persistence in vivo compared to conventional CD19-targeting CAR T cells. Overall, our results demonstrate that the cell-intrinsic PD-1/TIGIT dual downregulation strategy may provide an effective way to overcome the immune checkpoint-mediated resistance in CAR T therapy.
Project description:Only a minority of cancer patients benefit from immune checkpoint blockade therapy. Sophisticated cross-talk among different immune checkpoint pathways as well as interaction pattern of immune checkpoint molecules carried on circulating small extracellular vesicles (sEV) might contribute to the low response rate. Here we demonstrate that PD-1 and CD80 carried on immunocyte-derived sEVs (I-sEV) induce an adaptive redistribution of PD-L1 in tumour cells. The resulting decreased cell membrane PD-L1 expression and increased sEV PD-L1 secretion into the circulation contribute to systemic immunosuppression. PD-1/CD80+ I-sEVs also induce downregulation of adhesion- and antigen presentation-related molecules on tumour cells and impaired immune cell infiltration, thereby converting tumours to an immunologically cold phenotype. Moreover, synchronous analysis of multiple checkpoint molecules, including PD-1, CD80 and PD-L1, on circulating sEVs distinguishes clinical responders from those patients who poorly respond to anti-PD-1 treatment. Altogether, our study shows that sEVs carry multiple inhibitory immune checkpoints proteins, which form a potentially targetable adaptive loop to suppress antitumour immunity.
Project description:Anticancer T cells acquire a dysfunctional state characterized by poor effector function and expression of inhibitory receptors, such as programmed cell death protein 1 (PD-1). Blockade of PD-1 signalling leads to T cell reinvigoration and is increasingly applied as an effective anticancer treatment. Recent work challenged the commonly held view that the phosphatase Src homology 2 (SH2) domain–containing phosphatase (SHP)-2 is essential for the molecular cascade downstream PD-1, suggesting functional redundancy with the homologous phosphatase SHP-1. Therefore, we investigated the effect of concomitant SHP-1 and 2 deletion in T cells by knocking out these phosphatases under the CD4cre promoter. In vivo results not only indicate that Shp-1/2 deletion is insufficient to ameliorate tumour control, but also that it impairs the therapeutic effects of anti-PD1 treatment, affecting tumour-infiltrating CD8+ T cells. Notably, acute deletion of Shp-1/2 in effector T cells also fails to improve tumour control. In vitro results show that Shp-1/2-deleted CD8+ T cells exhibit impaired expansion due to a survival defect and proteomics analysis reveals substantial alterations in their proteome, including in apoptosis-related pathways. This data indicates that concomitant ablation of SHP-1/2 in polyclonal T cells fails to improve their anticancer properties, implying that caution shall be taken when considering their inhibition for immunotherapeutic approaches.
Project description:We studied whether Vγ9Vδ2-T cells can exploited as autologous effector lymphocytes in chronic lymphocytic leukemia (CLL). Healthy controls (HC) Vγ9Vδ2-T cells were activated by and had potent cytolytic activity against CLL cells, however CLL-derived Vγ9Vδ2-T cells proved dysfunctional with respect to effector cytokine production and cytotxicity. Dysfunction of Vγ9Vδ2-T cells was reversible upon activation with autologous monocyte-derived dendritic cells (mODCs). RNA sequencing confirmed that Vγ9Vδ2-T cells from CLL patients have a transcriptional profile that is distinct from HC Vγ9Vδ2-T cells prior to ex vivo expansion, although the profile after ex vivo expansion is similar between CLL and HC Vγ9Vδ2-T cells. Gene expression profiling implicated alterations in both synapse formation and exhaustion as conceivable contributors to compromised Vγ9Vδ2-T cell function in CLL patients. Taken together, CLL-mediated dysfunction of autologous Vγ9Vδ2-T cells is fully reversible, resulting in potent cytotoxicity towards CLL cells.
Project description:Vγ9Vδ2 T cells play an important role in the development and progression of psoriasis vulgaris (PV), but how they promote skin inflammation and the molecular mechanisms underlying Vγ9Vδ2 T cell dysfunction are poorly understood. Here, we show that circulating Vγ9Vδ2 T cells are decreased and exhibit enhanced proliferation and increased production of IFN-γ and TNF-α in PV patients. Monocytes from PV patients express higher levels of the phosphoantigen sensor butyrophilin 3A1 (BTN3A1) than monocytes from healthy controls. Blockade of BTN3A1 suppresses Vγ9Vδ2 T cell activation and abolishes the difference in Vγ9Vδ2 T cell activation between PV patients and healthy controls. The CD14+ cells in PV skin lesions highly express BTN3A1 and juxtapose to Vδ2 T cells. In addition, IFN-γ induces the up-regulation of BTN3A1 on monocytes. Collectively, our results demonstrate a crucial role of BTN3A1 on monocytes in regulating Vγ9Vδ2 T cell activation and highlight BTN3A1 as a potential therapeutic target for psoriasis.