Chemokine receptors expression and migration potential of tumor-infiltrating and peripheral-expanded Vgamma9Vdelta2 T cells from renal cell carcinoma patients

The capability of heterogeneous γδ T cells in cancer treatment

γδ T cells, a specialized subset of T lymphocytes, have garnered significant attention within the realm of cancer immunotherapy. Operating at the nexus between adaptive and innate immunological paradigms, these cells showcase a profound tumor discernment repertoire, hinting at novel immunotherapeutic strategies. Significantly, these cells possess the capability to directly identify and eliminate tumor cells without reliance on HLA-antigen presentation. Furthermore, γδ T cells have the faculty to present tumor antigens to αβ T cells, amplifying their anti-tumoral efficacy.Within the diverse and heterogeneous subpopulations of γδ T cells, distinct immune functionalities emerge, manifesting either anti-tumor or pro-tumor roles within the tumor microenvironment. Grasping and strategically harnessing these heterogeneous γδ T cell cohorts is pivotal to their integration in tumor-specific immunotherapeutic modalities. The aim of this review is to describe the heterogeneity of the γδ T cell lineage and the functional plasticity it generates in the treatment of malignant tumors. This review endeavors to elucidate the intricate heterogeneity inherent to the γδ T cell lineage, the consequential functional dynamics in combating malignancies, the latest advancements from clinical trials, and the evolving landscape of γδ T cell-based oncological interventions, while addressing the challenges impeding the field.

Innate lymphoid cells and innate-like T cells in cancer - at the crossroads of innate and adaptive immunity

Immunotherapies targeting conventional T cells have revolutionized systemic treatment for many cancers, yet only a subset of patients benefit from these approaches. A better understanding of the complex immune microenvironment of tumours is needed to design the next generation of immunotherapeutics. Innate lymphoid cells (ILCs) and innate-like T cells (ILTCs) are abundant, tissue-resident lymphocytes that have recently been shown to have critical roles in many types of cancers. ILCs and ILTCs rapidly respond to changes in their surrounding environment and act as the first responders to bridge innate and adaptive immunity. This places ILCs and ILTCs as pivotal orchestrators of the final antitumour immune response. In this Review, we outline hallmarks of ILCs and ILTCs and discuss their emerging role in antitumour immunity, as well as the pathophysiological adaptations leading to their pro-tumorigenic function. We explore the pleiotropic, in parts redundant and sometimes opposing, mechanisms that underlie the delicate interplay between the different subsets of ILCs and ILTCs. Finally, we highlight their role in amplifying and complementing conventional T cell functions and summarize immunotherapeutic strategies for targeting ILCs and ILTCs in cancer.

Human Vδ2 T Cells and Their Versatility for Immunotherapeutic Approaches

Gamma/delta (γδ) T cells are innate-like immune effectors that are a critical component linking innate and adaptive immune responses. They are recognized for their contribution to tumor surveillance and fight against infectious diseases. γδ T cells are excellent candidates for cellular immunotherapy due to their unique properties to recognize and destroy tumors or infected cells. They do not depend on the recognition of a single antigen but rather a broad-spectrum of diverse ligands through expression of various cytotoxic receptors. In this manuscript, we review major characteristics of the most abundant circulating γδ subpopulation, Vδ2 T cells, their immunotherapeutic potential, recent advances in expansion protocols, their preclinical and clinical applications for several infectious diseases and malignancies, and how additional modulation could enhance their therapeutic potential.

The Heterogeneity of the Tumor Microenvironment as Essential Determinant of Development, Progression and Therapy Response of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is commonly diagnosed at advanced stages and most anti-cancer therapies have failed to substantially improve prognosis of PDAC patients. As a result, PDAC is still one of the deadliest tumors. Tumor heterogeneity, manifesting at multiple levels, provides a conclusive explanation for divergent survival times and therapy responses of PDAC patients. Besides tumor cell heterogeneity, PDAC is characterized by a pronounced inflammatory stroma comprising various non-neoplastic cells such as myofibroblasts, endothelial cells and different leukocyte populations which enrich in the tumor microenvironment (TME) during pancreatic tumorigenesis. Thus, the stromal compartment also displays a high temporal and spatial heterogeneity accounting for diverse effects on the development, progression and therapy responses of PDAC. Adding to this heterogeneity and the impact of the TME, the microbiome of PDAC patients is considerably altered. Understanding this multi-level heterogeneity and considering it for the development of novel therapeutic concepts might finally improve the dismal situation of PDAC patients. Here, we outline the current knowledge on PDAC cell heterogeneity focusing on different stromal cell populations and outline their impact on PDAC progression and therapy resistance. Based on this information, we propose some novel concepts for treatment of PDAC patients.

γδ T Cells: The Ideal Tool for Cancer Immunotherapy

γδ T cells have recently gained considerable attention as an attractive tool for cancer adoptive immunotherapy due to their potent anti-tumor activity and unique role in immunosurveillance. The remarkable success of engineered T cells for the treatment of hematological malignancies has revolutionized the field of adoptive cell immunotherapy. Accordingly, major efforts are underway to translate this exciting technology to the treatment of solid tumors and the development of allogeneic therapies. The unique features of γδ T cells, including their major histocompatibility complex (MHC)-independent anti-cancer activity, tissue tropism, and multivalent response against a broad spectrum of the tumors, render them ideal for designing universal 'third-party' cell products, with the potential to overcome the challenges of allogeneic cell therapy. In this review, we describe the crucial role of γδ T cells in anti-tumor immunosurveillance and we summarize the different approaches used for the ex vivo and in vivo expansion of γδ T cells suitable for the development of novel strategies for cancer therapy. We further discuss the different transduction strategies aiming at redirecting or improving the function of γδ T cells, as well as, the considerations for the clinical applications.

In vitro expansion of Vγ9Vδ2 T cells for immunotherapy

Vγ9Vδ2 T cells can exhibit potent anti-tumor activity and have gained much attention as an interesting tool for cancer immunotherapy by adoptive cell transfer. In this chapter, we explain the different approaches for the in vitro expansion of Vγ9Vδ2 T cells for their subsequent adoptive transfer and present a detailed protocol for the successful in vitro expansion at the laboratory scale. Finally, we discuss strategies for optimization and parameters necessary for the adaption to a clinical scale protocol.

Antigen-Presenting Cell Characteristics of Human γδ T Lymphocytes in Chronic Myeloid Leukemia

Human γδ T lymphocytes play a role in the immune system defense against cancer. Their broad anti-cancer activity against different types of cancers makes them outstanding candidates for cancer immunotherapy. An issue of recent interest is whether their antigen presentation features are similar to mature dendritic cells. The antigen-presenting cell (APC)-like phenotype and function of γδ T lymphocytes have been confirmed in many clinical trials. In this study, to support the strong role played by Vγ9Vδ2 T cells against cancer, we provide evidence that Vγ9Vδ2 T cells activated with chronic myeloid leukemia (CML) cell lysate antigens can efficiently express an APC phenotype and function. Vγ9Vδ2 T cells derived from normal peripheral blood mononuclear cells were activated with tumor cell lysate, and the tumor-activated Vγ9Vδ2 T cells could recognize and kill CML through their cytotoxic activity. In conclusion, the Vγ9Vδ2 T cells activated by cancer cell lysate showed APC characteristics, and this may greatly increase interest in investigating their therapeutic potential in hematologic malignancies. Abbreviations: CML: chronic myeloid leukemia; APC: antigen-presenting cell; TCR: T cell receptor; MHC: major histocompatibility complex; N-BPs: nitrogen-containing bisphosphonates; IPP: isopentenyl pyrophosphate; PBMC: peripheral blood mononuclear cells; NKG2D: natural killer receptor group 2, member D; TRAIL: tumor necrosis factor-related apoptosis-inducing ligand.

The role of the common gamma-chain family cytokines in γδ T cell-based anti-cancer immunotherapy

Cytokines of the common gamma-chain receptor family, comprising interleukin (IL)-2, IL-4, IL-7, IL-9, IL-15 and IL-21, are vital with respect to organizing and sustaining healthy immune cell functions. Supporting the anti-cancer immune response, these cytokines inspire great interest for their use as vaccine adjuvants and cancer immunotherapies. It is against this background that gamma delta (γδ) T cells, as special-force soldiers and natural contributors of the tumor immunosurveillance, also received a lot of attention the last decade. As γδ T cell-based cancer trials are coming of age, this present review focusses on the effects of the different cytokines of the common gamma-chain receptor family on γδ T cells with respect to boosting γδ T cells as a therapeutic target in cancer immunotherapy. This review also gathers data that IL-15 in particular exhibits key features for augmenting the anti-tumor activity of effector killer γδ T cells whilst overcoming the myriad of immune escape mechanisms used by cancer cells.

Improving the Efficiency of Vγ9Vδ2 T-Cell Immunotherapy in Cancer

Increasing immunological knowledge and advances in techniques lay the ground for more efficient and broader application of immunotherapies. gamma delta (γδ) T-cells possess multiple favorable anti-tumor characteristics, making them promising candidates to be used in cellular and combination therapies of cancer. They recognize malignant cells, infiltrate tumors, and depict strong cytotoxic and pro-inflammatory activity. Here, we focus on human Vγ9Vδ2 T-cells, the most abundant γδ T-cell subpopulation in the blood, which are able to inhibit cancer progression in various models in vitro and in vivo. For therapeutic use they can be cultured and manipulated ex vivo and in the following adoptively transferred to patients, as well as directly stimulated to propagate in vivo. In clinical studies, Vγ9Vδ2 T-cells repeatedly demonstrated a low toxicity profile but hitherto only the modest therapeutic efficacy. This review provides a comprehensive summary of established and newer strategies for the enhancement of Vγ9Vδ2 T-cell anti-tumor functions. We discuss data of studies exploring methods for the sensitization of malignant cells, the improvement of recognition mechanisms and cytotoxic activity of Vγ9Vδ2 T-cells. Main aspects are the tumor cell metabolism, antibody-dependent cell-mediated cytotoxicity, antibody constructs, as well as activating and inhibitory receptors like NKG2D and immune checkpoint molecules. Several concepts show promising results in vitro, now awaiting translation to in vivo models and clinical studies. Given the array of research and encouraging findings in this area, this review aims at optimizing future investigations, specifically targeting the unanswered questions.

γδ cells and tumor microenvironment: A helpful or a dangerous liason?

γδ T cells are a subset of T lymphocytes that have been implicated in immunosurveillance against infections and tumors. γδ T cells are endowed with antitumor activities, and hence several γδ T cell-based small-scale clinical trials have been conducted either by in vivo activation by intravenous administration of aminobiphosphonates or by adoptive transfer of in vitro expanded γδ T cells. Although both these strategies have yielded promising results, there are a number of limitations associated with each of them which, if overcome may help to further improve efficacy. One of the most important limits is the possible polarization of tumor-infiltrating γδ T cells toward different γδ T cells population with functional activities that help the progression and spread of the tumor. Here, we review the modalities and the possible mechanisms involved in the polarization of tumor-infiltrating γδ T cells upon interaction with several components of the tumor microenvironment and discuss their implications for the manipulation of γδ T cells in cancer immunotherapy.

Nano-technology based carriers for nitrogen-containing bisphosphonates delivery as sensitisers of γδ T cells for anticancer immunotherapy

Nitrogen containing bisphosphonates (N-BPs) including zoledronate (ZOL) and alendronate (ALD) inhibit farnesyl diphosphate synthase, and have been shown to have a cytotoxic affect against cancer cells as a monotherapy and to also sensitise tumour cells to destruction by γδ T cells. γδ T cells are a subset of human T lymphocytes and have a diverse range of roles in the immune system including the recognition and destruction of cancer cells. This property of γδ T cells can be harnessed for use in cancer immunotherapy through in vivo expansion or the adoptive transfer of ex vivo activated γδ T cells. The use of N-BPs with γδ T cells has been shown to have a synergistic effect in in vitro, animal and clinical studies. N-BPs have limited in vivo activity due to rapid clearance from the circulation. By encapsulating N-BPs in liposomes (L) it is possible to increase the levels of N-BPs at non-osseous tumour sites. L-ZOL and L-ALD have been shown to have different toxicological profiles than free ZOL or ALD. Both L-ALD and L-ZOL led to increased spleen weight, leucocytosis, neutrophilia and lymphocytopenia in mice after intravenous injection. L-ALD was shown to be better tolerated than L-ZOL in murine studies. Biodistribution studies have been performed in order to better understand the interaction of N-BPs and γδ T cells in vivo. Additionally, in vivo therapy studies have shown that mice treated with both L-ALD and γδ T cells had a significant reduction in tumour growth compared to mice treated with L-ALD or γδ T cells alone. The use of ligand-targeted liposomes may further increase the efficacy of this combinatory immunotherapy. Liposomes targeting the αvβ6 integrin receptor using the peptide A20FMDV2 had a greater ability than untargeted liposomes in sensitising cancer cells to destruction by γδ T cells in αvβ6 positive cancer cell lines.

Interleukin-15 enhances the proliferation, stimulatory phenotype, and antitumor effector functions of human gamma delta T cells

Background

Adoptive immunotherapy is gaining momentum to fight malignancies, whereby γδ T cells have received recent attention as an alternative cell source as to natural killer cells and αβ T cells. The advent of γδ T cells is largely due to their ability to recognize and target tumor cells using both innate characteristic and T cell receptor (TCR)-mediated mechanisms, their capacity to enhance the generation of antigen-specific T cell responses, and their potential to be used in an autologous or allogeneic setting.

Methods

In this study, we explored the beneficial effect of the immunostimulatory cytokine interleukin (IL)-15 on purified γδ T cells and its use as a stimulatory signal in the ex vivo expansion of γδ T cells for adoptive transfer. The expansion protocol was validated both with immune cells of healthy individuals and acute myeloid leukemia patients.

Results

We report that the addition of IL-15 to γδ T cell cultures results in a more activated phenotype, a higher proliferative capacity, a more pronounced T helper 1 polarization, and an increased cytotoxic capacity of γδ T cells. Moreover γδ T cell expansion starting with peripheral blood mononuclear cells from healthy individuals and acute myeloid leukemia patients is boosted in the presence of IL-15, whereby the antitumor properties of the γδ T cells are strengthened as well.

Conclusions

Our results support the rationale to explore the use of IL-15 in clinical adoptive therapy protocols exploiting γδ T cells.

Adoptive Cellular Therapy (ACT) for Cancer Treatment

Adoptive cellular therapy (ACT) with various lymphocytes or antigen-presenting cells is one stone in the pillar of cancer immunotherapy, which relies on the tumor-specific T cell. The transfusion of bulk T-cell population into patients is an effective treatment for regression of cancer. In this chapter, we summarize the development of various strategies in ACT for cancer immunotherapy and discuss some of the latest progress and obstacles in technical, safety, and even regulatory aspects to translate these technologies to the clinic. ACT is becoming a potentially powerful approach to cancer treatment. Further experiments and clinical trials are needed to optimize this strategy.

Harnessing the power of Vδ2 cells in cancer immunotherapy

γδ T cells are a subset of T lymphocytes that have been implicated in immunosurveillance against infections and tumours. In the peripheral blood of humans the γδ T cell pool is made up predominantly of Vδ2 cells, which can detect both foreign and self-metabolites of the isoprenoid biosynthesis pathway. This unique axis of antigen recognition enables Vδ2 cells to respond to a range of pathogenic infections as well as perturbations in endogenous isoprenoid biosynthesis that can occur during cell stress and malignant transformation. There has been growing interest in Vδ2 cells as a potential avenue for cancer immunotherapy, and a number of strategies have been utilized in an attempt to boost the anti-tumour response of Vδ2 cells in patients. In this review we discuss critically the evidence that Vδ2 cells contribute to the cytotoxic response against tumours and evaluate current immunotherapeutic approaches that target these cells in cancer patients, with specific focus on their shortcomings and how they may be improved.

The Jekyll and Hyde story of IL17-Producing γδT Cells

In comparison to conventional αβT cells, γδT cells are considered as specialized T cells based on their contributions in regulating immune response. γδT cells sense early environmental signals and initiate local immune-surveillance. The development of functional subtypes of γδT cells takes place in the thymus but they also exhibit plasticity in response to the activating signals and cytokines encountered in the extrathymic region. Thymic development of Tγδ1 requires strong TCR, CD27, and Skint-1 signals. However, differentiation of IL17-producing γδT cells (Tγδ17) is independent of Skint-1 or CD27 but requires notch signaling along with IL6 and TGFβ cytokines in the presence of weak TCR signal. In response to cytokines like IL23, IL6, and IL1β, Tγδ17 outshine Th17 cells for early activation and IL17 secretion. Despite expressing similar repertoire of lineage transcriptional factors, cytokines, and chemokine receptors, Tγδ17 cells differ from Th17 in spatial and temporal fashion. There are compelling reasons to consider significant role of Tγδ17 cells in regulating inflammation and thereby disease outcome. Tγδ17 cells regulate mobilization of innate immune cells and induce keratinocytes to secrete anti-microbial peptides thus exhibiting protective functions in anti-microbial immunity. In contrast, dysregulated Tγδ17 cells inhibit Treg cells, exacerbate autoimmunity, and are also known to support carcinogenesis by enhancing angiogenesis. The mechanism associated with this dual behavior of Tγδ17 is not clear. To exploit, Tγδ17 cells for beneficial use requires comprehensive analysis of their biology. Here, we summarize the current understanding on the characteristics, development, and functions of Tγδ17 cells in various pathological scenarios.

Plasticity of γδ T Cells: Impact on the Anti-Tumor Response

The tumor immune microenvironment contributes to tumor initiation, progression, and response to therapy. Among the immune cell subsets that play a role in the tumor microenvironment, innate-like T cells that express T cell receptors composed of γ and δ chains (γδ T cells) are of particular interest. γδ T cells can contribute to the immune response against many tumor types (lymphoma, myeloma, melanoma, breast, colon, lung, ovary, and prostate cancer) directly through their cytotoxic activity and indirectly by stimulating or regulating the biological functions of other cell types required for the initiation and establishment of the anti-tumor immune response, such as dendritic cells and cytotoxic CD8+ T cells. However, the notion that tumor-infiltrating γδ T cells are a good prognostic marker in cancer was recently challenged by studies showing that the presence of these cells in the tumor microenvironment was associated with poor prognosis in both breast and colon cancer. These findings suggest that γδ T cells may also display pro-tumor activities. Indeed, breast tumor-infiltrating γδ T cells could exert an immunosuppressive activity by negatively regulating dendritic cell maturation. Furthermore, recent studies demonstrated that signals from the microenvironment, particularly cytokines, can confer some plasticity to γδ T cells and promote their differentiation into γδ T cells with regulatory functions. This review focuses on the current knowledge on the functional plasticity of γδ T cells and its effect on their anti-tumor activities. It also discusses the putative mechanisms underlying γδ T cell expansion, differentiation, and recruitment in the tumor microenvironment.

The feature of distribution and clonality of TCR γ/δ subfamilies T cells in patients with B-cell non-Hodgkin lymphoma

Restricted T-cell receptor (TCR) Vα/Vβ repertoire expression and clonal expansion of αβ T cells especially for putative tumor-associated antigens were observed in patients with hematological malignancies. To further characterize the γδ T-cell immune status in B-cell non-Hodgkin lymphoma (B-NHL), we investigated the distribution and clonality of TCR Vγ/Vδ repertoire in peripheral blood (PB), bone marrow (BM), and lymph node (LN) from patients with B-NHL. Four newly diagnosed B-NHL cases, including three with diffuse large B-cell lymphoma (DLBCL) and one with small lymphocytic lymphoma (SLL), were enrolled. The restrictive expression of TCR Vγ/Vδ subfamilies with different distribution patterns could be detected in PB, BM, or LN from all of four patients, and partial subfamily T cells showed clonal proliferation. At least one clonally expanded Vδ subfamily member was found in PB from each patient. However, the expression pattern and clonality of TCR Vγ/Vδ changed in different immune organs and showed individual feature in different patients. The clonally expanded Vδ5, Vδ6, and Vδ8 were detected only in PB but neither in BM nor LN while clonally expanded Vδ2 and Vδ3 could be detected in both PB and BM/LN. In conclusion, the results provide a preliminary profile of distribution and clonality of TCR γ/δ subfamilies T cells in PB, BM, and LN from B-NHL; similar clonally expanded Vδ subfamily T cells in PB and BM may be related to the same B-cell lymphoma-associated antigens, while the different reactive clonally expanded Vγ/Vδ T cells may be due to local immune response.

Manipulating immune cells for adoptive immunotherapy of cancer

The immune system can be induced to respond against cancer with some success reported in clinical trials using a range of approaches including vaccines and antibodies. In addition to these approaches, cell based therapies are demonstrating much promise as potential therapies for cancer. In cell therapies autologous patient leukocytes are isolated and manipulated in vitro before transfer back to the patient in adoptive transfer regimens. The majority of approaches utilize conventional T cells or dendritic cells, but a wide variety of other types of leukocytes exist which can possess anti-cancer activity. In this review, we present a brief overview of T cell adoptive cell transfer followed by a review of approaches using alternate lymphocyte subsets and other leukocytes including neutrophils, macrophages and eosinophils.

Novel bispecific antibodies increase γδ T-cell cytotoxicity against pancreatic cancer cells

The ability of human γδ T cells from healthy donors to kill pancreatic ductal adenocarcinoma (PDAC) in vitro and in vivo in immunocompromised mice requires the addition of γδ T-cell-stimulating antigens. In this study, we demonstrate that γδ T cells isolated from patients with PDAC tumor infiltrates lyse pancreatic tumor cells after selective stimulation with phosphorylated antigens. We determined the absolute numbers of γδ T-cell subsets in patient whole blood and applied a real-time cell analyzer to measure their cytotoxic effector function over prolonged time periods. Because phosphorylated antigens did not optimally enhance γδ T-cell cytotoxicity, we designed bispecific antibodies that bind CD3 or Vγ9 on γδ T cells and Her2/neu (ERBB2) expressed by pancreatic tumor cells. Both antibodies enhanced γδ T-cell cytotoxicity with the Her2/Vγ9 antibody also selectively enhancing release of granzyme B and perforin. Supporting these observations, adoptive transfer of γδ T cells with the Her2/Vγ9 antibody reduced growth of pancreatic tumors grafted into SCID-Beige immunocompromised mice. Taken together, our results show how bispecific antibodies that selectively recruit γδ T cells to tumor antigens expressed by cancer cells illustrate the tractable use of endogenous γδ T cells for immunotherapy.

Colorectal cancer defeating? Challenge accepted!

Colorectal tumours are actually considered as aberrant organs, within it is possible to notice a different stage of cell growth and differentiation. Their origin is reported to arise from a subpopulation of tumour cells endowed with, just like the healthy stem cells, self-renewal and aberrant multi-lineage differentiation capacity likely to be called colorectal cancer stem cells (CCSCs). Cancer stem cells (CSCs) fate, since their origin, reflects the influences from their microenvironment (or niche) both in the maintenance of stemness, in promoting their differentiation, and in inducing epithelial-mesenchymal transition, responsible of CSCs dissemination and subsequent formation of metastatic lesions. The tumour cells heterogeneity and their immuno-response resistance nowadays probably responsible of the failure of the conventional therapies, make this research field an open issue. Even more importantly, our increasing understanding of the cellular and molecular mechanisms that regulate CSC quiescence and cell cycle regulation, self-renewal, chemotaxis and resistance to cytotoxic agents, is expected to eventually result in tailor-made therapies with a significant impact on the morbidity and overall survival of colorectal cancer patients.

A quantitative deficiency in peripheral blood Vγ9Vδ2 cells is a negative prognostic biomarker in ovarian cancer patients

Vγ9Vδ2 cells are cytotoxic T cells that are able to recognize epithelial ovarian carcinoma (EOC) cells. Therefore, Vγ9Vδ2 cell-based adoptive transfer is an attractive therapy for EOC. However, the inefficient ex vivo expansion after specific stimulation of Vγ9Vδ2 cells from some patients and the relationships between Vγ9Vδ2 cells and clinical course of EOC are issues that remain to be clarified. Herein, peripheral blood mononuclear cells (PBMCs) from 60 EOC patients were stimulated with bromohydrin pyrophosphate (BrHPP) or zoledronate, which are specific agonists of Vγ9Vδ2 cells. The compounds differed in their efficacies to induce ex vivo Vγ9Vδ2 PBMC expansion, but 16/60 samples remained inefficiently expanded with both stimuli. Interestingly, the Vγ9Vδ2 cells in these low-responding PBMCs displayed before expansion (ex vivo PBMCs) an altered production of the pro-inflammatory cytokines IFN-γ and TNF-α, a decreased naive fraction and a reduced frequency. No evidence of an involvement of CD4⁺CD25⁺Foxp3⁺ regulatory cells was observed. Importantly, our data also demonstrate that a Vγ9Vδ2 cell frequency of 0.35% or less in EOC PBMCs could be used to predict low responses to both BrHPP and zoledronate. Moreover, our data highlight that such a deficiency is not correlated with advanced EOC stages but is associated with more refractory states to platinum-based chemotherapy and is an independent predictor of shorter disease-free survival after treatment. These results are the first to suggest a potential contribution of Vγ9Vδ2 cells to the anti-tumor effects of chemotherapeutic agents and they strengthen interest in strategies that might increase Vγ9Vδ2 cells in cancer patients.

Extensive expansion of primary human gamma delta T cells generates cytotoxic effector memory cells that can be labeled with Feraheme for cellular MRI

Gamma delta T cells (GDTc) comprise a small subset of cytolytic T cells shown to kill malignant cells in vitro and in vivo. We have developed a novel protocol to expand GDTc from human blood whereby GDTc were initially expanded in the presence of alpha beta T cells (ABTc) that were then depleted prior to use. We achieved clinically relevant expansions of up to 18,485-fold total GDTc, with 18,849-fold expansion of the Vδ1 GDTc subset over 21 days. ABTc depletion yielded 88.1 ± 4.2 % GDTc purity, and GDTc continued to expand after separation. Immunophenotyping revealed that expanded GDTc were mostly CD27-CD45RA- and CD27-CD45RA+ effector memory cells. GDTc cytotoxicity against PC-3M prostate cancer, U87 glioblastoma and EM-2 leukemia cells was confirmed. Both expanded Vδ1 and Vδ2 GDTc were cytotoxic to PC-3M in a T cell antigen receptor- and CD18-dependent manner. We are the first to label GDTc with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles for cellular MRI. Using protamine sulfate and magnetofection, we achieved up to 40 % labeling with clinically approved Feraheme (Ferumoxytol), as determined by enumeration of Perls' Prussian blue-stained cytospins. Electron microscopy at 2,800× magnification verified the presence of internalized clusters of iron oxide; however, high iron uptake correlated negatively with cell viability. We found improved USPIO uptake later in culture. MRI of GDTc in agarose phantoms was performed at 3 Tesla. The signal-to-noise ratios for unlabeled and labeled cells were 56 and 21, respectively. Thus, Feraheme-labeled GDTc could be readily detected in vitro via MRI.

What lessons can be learned from γδ T cell-based cancer immunotherapy trials?

During the last several years, research has produced a significant amount of knowledge concerning the characteristics of human γδ T lymphocytes. Findings regarding the immune functions of these cells, particularly their natural killer cell-like lytic activity against tumor cells, have raised expectations for the therapeutic applications of these cells for cancer. Pharmaceutical companies have produced selective agonists for these lymphocytes, and several teams have launched clinical trials of γδ T cell-based cancer therapies. The findings from these studies include hematological malignancies (follicular lymphoma, multiple myeloma, acute and chronic myeloid leukemia), as well as solid tumors (renal cell, breast and prostate carcinomas), consisting of samples from more than 250 patients from Europe, Japan and the United States. The results of these pioneering studies are now available, and this short review summarizes the lessons learned and the role of γδ T cell-based strategies in the current landscape of cancer immunotherapies.

Anti-tumour immunotherapy with Vγ9Vδ2 T lymphocytes: from the bench to the bedside

Gamma delta (γδ) Τ cells are non-conventional T lymphocyte effectors that can interact with and eradicate tumour cells. Several data demonstrate that these T cells, which are implicated in the first line of defence against pathogens, have anti-tumour activity against many cancers and suggest that γδ Τ cell-mediated immunotherapy is feasible and might induce objective tumour responses. Due to the importance of γδ Τ lymphocytes in the induction and control of immunity, a complete understanding of their biology is crucial for the development of a potent cancer immunotherapy. This review discusses recent advances in γδ Τ basic research and data from clinical trials on the use of γδ Τ cells in the treatment of different cancers. It analyses how this knowledge might be applied to develop new strategies for the clinical manipulation and the potentiation of γδ Τ lymphocyte activity in cancer immunotherapy.

Role of gamma-delta T-cells in cancer: another opening door to immunotherapy

The gamma-delta (γδ) T-cells are a subset of T-lymphocytes characterized by the presence of a surface antigen recognition complex type 2. Those γδ T-cells represent 2-5 % of peripheral T-cells only, but they are common in organs and mucosae, acting as a first defense system in the entries to the organism. The γδ T-cells take part on immune response by direct cytolysis, development of memory phenotypes, and modulation of immune cells, and they have been implied in autoimmune disorders, immune deficiencies, infections, and tumor diseases. We reported the role of γδ T-cells in oncology, focusing in their potential applications for cancer treatment. Experimental designs and clinical trials in the treatment of solid malignancies are extensively reviewed.

How tumors might withstand γδ T-cell attack

Several clinical trials are currently assessing the therapeutic activity of human TCRVγ9Vδ2(+) lymphocytes in cancer. Growing tumors usually follow a triphasic "Elimination, Equilibrium, Escape" evolution in patients. Thus, at diagnostic, most tumors have already developed some means to escape to immune protection. We review here the conventional immunoescape mechanisms which might also protect against cytolytic TCRVγ9Vδ2(+) lymphocytes activated by phosphoantigens. Neutralization of these deleterious processes might prove highly valuable to improve the efficacy of ongoing γδ cell-based cancer immunotherapies.

Anti-leukemia activity of in vitro-expanded human gamma delta T cells in a xenogeneic Ph+ leukemia model

Gamma delta T cells (GDTc) lyse a variety of hematological and solid tumour cells in vitro and in vivo, and are thus promising candidates for cellular immunotherapy. We have developed a protocol to expand human GDTc in vitro, yielding highly cytotoxic Vgamma9/Vdelta2 CD27/CD45RA double negative effector memory cells. These cells express CD16, CD45RO, CD56, CD95 and NKG2D. Flow cytometric, clonogenic, and chromium release assays confirmed their specific cytotoxicity against Ph(+) cell lines in vitro. We have generated a fluorescent and bioluminescent Ph(+) cell line, EM-2eGFPluc, and established a novel xenogeneic leukemia model. Intravenous injection of EM-2eGFPluc into NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice resulted in significant dose-dependent bone marrow engraftment; lower levels engrafted in blood, lung, liver and spleen. In vitro-expanded human GDTc injected intraperitoneally were found at higher levels in blood and organs compared to those injected intravenously; GDTc survived at least 33 days post-injection. In therapy experiments, we documented decreased bone marrow leukemia burden in mice treated with GDTc. Live GDTc were found in spleen and bone marrow at endpoint, suggesting the potential usefulness of this therapy.

gammadelta T cells in cancer immunotherapy: current status and future prospects

gammadelta T lymphocytes are a distinct T-cell subset that display unique features with respect to T-cell receptor (TCR) gene usage, tissue tropism and antigen recognition. Phosphoantigens contributed by a dysregulated mevalonate pathway or the bacterial nonmevalonate pathway and aminobisphosphonates are capable of activating Vgamma9Vdelta2 T cells. With the aid of synthetic phosphoantigens, large-scale expansion of gammadelta T cells and their adoptive transfer into human hosts is now possible. The present review summarizes triumphs and tribulations of clinical trials using gammadelta T-cell immunotherapy. Adoptive transfer of phosphoantigen-activated gammadelta T cells or coadministration with aminobisphosphonates/cytokines/monoclonal antibodies appear to be promising approaches for cancer immunotherapy. It can be predicted that a comprehensive understanding of the molecular interactions of this unique T-cell subset with other key immune regulators (dendritic cells and regulatory T cells) will provide an impetus to bring this modality of treatment from bench to bedside.

γδ T cells cross-link innate and adaptive immunity in Mycobacterium tuberculosis infection

Protective immunity against mycobacterial infections such as Mycobacterium tuberculosis is mediated by interactions between specific T cells and activated antigen presenting cells. To date, many aspects of mycobacterial immunity have shown that innate cells could be the key elements that substantially may influence the subsequent adaptive host response. During the early phases of infection, innate lymphocyte subsets play a pivotal role in this context. Here we summarize the findings of recent investigations on γδ T lymphocytes and their role in tuberculosis immunity.

γδ T-cell killing of primary follicular lymphoma cells is dramatically potentiated by GA101, a type II glycoengineered anti-CD20 monoclonal antibody

BACKGROUND

Anti-CD20 monoclonal antibodies are major therapeutic agents for patients with follicular lymphoma and work through complement-mediated cytotoxicity and antibody-dependent cellular cytotoxicity. Optimization of antibody-dependent cellular cytotoxicity, in particular by amplifying its effectors, could further increase the efficacy of anti-CD20 monoclonal antibodies.

DESIGN AND METHODS

We investigated the cytotoxic activity of Vγ9Vδ2 T cells against follicular lymphoma cells and whether this killing could be increased by promoting antibody-dependent cellular cytotoxicity with anti-CD20 monoclonal antibodies, in particular a type-II glycoengineered anti-CD20. Vγ9Vδ2 T cells were expanded in vitro in the presence of bromohydrin pyrophosphate (Phosphostim) and interleukin-2 and their ability to kill follicular lymphoma primary cells or cell lines was evaluated by flow cytometry cytotoxic T-lymphocyte assays in the presence or absence of three anti-CD20 monoclonal antibodies: the afucosylated GA101, the chimeric rituximab or the humanized ofatumumab. The ability of these cells to release perforin/granzyme and secrete interferon-γ when co-cultured with follicular lymphoma primary cells or cell lines in the presence or not of the three anti-CD20 monoclonal antibodies was also evaluated by CD107a staining and Elispot assays.

RESULTS

Phosphostim and interleukin-2 expanded Vγ9Vδ2 T cells were cytotoxic to primary follicular lymphoma cells and their cytotoxic potential was dramatically increased by GA101, a type II glycoengineered anti-CD20 monoclonal antibody, and to a lesser extent, by rituximab and ofatumumab. The increased cytotoxicity was associated with increased secretion of perforin/granzyme and interferon-γ.

CONCLUSIONS

In-vitro expanded Vγ9Vδ2 T cells efficiently kill primary follicular lymphoma cells and express CD16; anti-CD20 monoclonal antibodies, in particular GA101, dramatically increase the cytotoxic activity of expanded Vγ9Vδ2 T cells. These preclinical results prompt the development of clinical trials using this antibody dependent cellular cytotoxicity property of Vγ9Vδ2 T cells and anti-CD20 monoclonal antibodies.

Phase I study of bromohydrin pyrophosphate (BrHPP, IPH 1101), a Vgamma9Vdelta2 T lymphocyte agonist in patients with solid tumors

PURPOSE

Vgamma9Vdelta2 (gammadelta) T lymphocytes, a critical peripheral blood lymphocyte subset, are directly cytotoxic against many solid and hematologic tumor types. Vgamma9Vdelta2 T lymphocytes can be selectively expanded in vivo with BrHPP (IPH1101) and IL-2. The present phase I trial was conducted with the aim of determining the maximum-tolerated dose (MTD) and safety of IPH1101 combined with a low dose of IL-2 in patients with solid tumors.

EXPERIMENTAL DESIGN

A 1-h intravenous infusion of IPH11 was administered alone at cycle 1, combined with a low dose of SC IL-2 (1 MIU/M(2) d1 to d7) in the subsequent cycles (day 1 every 3 weeks). The dose of IPH1101 was escalated from 200 to 1,800 mg/m(2).

RESULTS

As much as 28 patients with solid tumors underwent a total of 109 treatment cycles. Pharmacodynamics data demonstrate that gammadelta T lymphocyte amplification in humans requires the co-administration of IL-2 and is dependent on IPH 1101 dose. Dose-limiting toxicity occurred in two patients at a dose of 1,800 mg/m(2): one grade 3 fever (1 patient) and one grade 3 hypotension (1 patient) suggesting cytokine release syndrome immediately following the first infusion. At lower doses the treatment was well tolerated; the most frequent adverse events were mild fever, chills and abdominal pain, without exacerbation in the IL-2 combined cycles.

CONCLUSION

IPH1101 in combination with SC low-dose IL-2 is safe, well tolerated and induces a potent gammadelta T lymphocyte expansion in patients. Its clinical activity will be evaluated in phase II clinical trials.

Alterations of the gene expression profile in renal cell carcinoma after treatment with the histone deacetylase-inhibitor valproic acid and interferon-alpha

PURPOSE

Renal cell carcinoma (RCC) is highly resistant to chemotherapy and unresponsive to radio- and immunotherapy. Recently, we have documented that the histone deacetylase (HDAC)-inhibitor valproic acid (VPA) in combination with low-dosed interferon (IFN)-alpha significantly inhibits RCC proliferation and adhesion in vitro and in vivo. The current study investigated the effects of these compounds on gene transcription of metastatic RCC cell line Caki-1 after 3 and 5 days exposure.

METHODS

To evaluate the gene expression profiles of the RCC cells, we performed microarray analysis using Affymetrix GeneChip. Selected significant genes were further validated by Real Time PCR.

RESULTS

Microarray revealed that VPA altered genes that are involved in cell growth, cell survival, immune response, cell motility and cell adhesion. Combination of VPA with IFN-alpha not only enhanced the effects on gene transcription but also resulted in the expression of novel genes, which were not induced by either VPA or IFN-alpha alone. Among the up-regulated genes were chemokines (CXCL10, CXCL11, CXCL16) and integrins (ITGA2, ITGA4, ITGA5, ITGA6, ITGA7). Genes encoding for adhesion molecules (NCAM1, ICAM1, VCAM1) were also modulated. Real Time PCR approved these findings.

CONCLUSION

This data provides insight into the molecular mechanism of action of the combined treatment of VPA and IFN-alpha in RCC. Implications are that the combined application of VPA and IFN-alpha may represent a more efficient alternative to existing therapy options for RCC.

Toll-like receptors 3 and 7 agonists enhance tumor cell lysis by human gammadelta T cells

Toll-like receptor (TLR) agonists are considered adjuvants in clinical trials of cancer immunotherapy. Here, we investigated the modulation of gammadelta T cell-mediated tumor cell lysis by TLR ligands. gammadelta T-cell cytotoxicity and granzyme A/B production were enhanced after pretreatment of tumor cells with TLR3 [poly(I:C)] or TLR7 ligand (imiquimod). We examined TLR3- and TLR7-expressing pancreatic adenocarcinomas, squamous cell carcinomas of head and neck and lung carcinomas. Poly(I:C) treatment of pancreatic adenocarcinomas followed by coculture with gammadelta T cells resulted in an upregulation of CD54 on the tumor cells. The interaction of CD54 and the corresponding ligand CD11a/CD18 expressed on gammadelta T cells is responsible for triggering effector function in gammadelta T cells. Moreover, treatment with imiquimod downregulated MHC class I molecules on tumor cells possibly resulting in a reduced binding affinity for inhibitory receptor NKG2A expressed on gammadelta T cells. These results indicate that TLR3 or TLR7 ligand stimulation of tumor cells enhances the cytotoxic activity of expanded gammadelta T cells of cancer patients in vitro.

T cell-based immunotherapy of metastatic renal cell carcinoma: modest success and future perspective

Metastatic renal cell carcinoma (MRCC) remains a challenging malignancy to treat. Cancer immunotherapies have been extensively explored in melanoma and RCC as they poorly respond to conventional cytotoxic agents but show responses to a variety of immunologic agents. The recent considerable success of T cell-based immunotherapy in melanoma warrants further efforts to apply this treatment to other cancers including MRCC. Although RCC is an immunosensitive cancer, similar attempts in MRCC have shown a very limited success. In this review, we summarize the clinical data on T cell-based immunotherapies for MRCC showing the modest success that has been achieved to date. More importantly, we discuss potential strategies for improving its efficacy for the treatment of MRCC in light of the important achievements for treating metastatic melanoma. In particular, the growing evidence of success by combining expanded tumor-infiltrating lymphocytes with lymphodepletion merits investigation in MRCC. Identifying new RCC-associated antigens, optimized methods, and conditions for detection, isolation, and/or modification and expansion of tumor-specific T cells are all important strategies to be pursued for improving T cell-based immunotherapy of MRCC.

Efficient killing of human colon cancer stem cells by gammadelta T lymphocytes

Colon cancer comprises a small population of cancer stem cells (CSC) that is responsible for tumor maintenance and resistant to cancer therapies, possibly allowing for tumor recapitulation once treatment stops. We previously demonstrated that such chemoresistance is mediated by autocrine production of IL-4 through the up-regulation of antiapoptotic proteins. Several innate and adaptive immune effector cells allow for the recognition and destruction of cancer precursors before they constitute the tumor mass. However, cellular immune-based therapies have not been experimented yet in the population of CSCs. Here, we show that the bisphosphonate zoledronate sensitizes colon CSCs to Vgamma9Vdelta2 T cell cytotoxicity. Proliferation and production of cytokines (TNF-alpha and IFN-gamma) and cytotoxic and apoptotic molecules (TRAIL and granzymes) were also induced after exposure of Vgamma9Vdelta2 T cells to sensitized targets. Vgamma9Vdelta2 T cell cytotoxicity was mediated by the granule exocytosis pathway and was highly dependent on isoprenoid production by of tumor cells. Moreover, CSCs recognition and killing was mainly TCR mediated, whereas NKG2D played a role only when tumor targets expressed several NKG2D ligands. We conclude that intentional activation of Vgamma9Vdelta2 T cells by zoledronate may substantially increase antitumor activities and represent a novel strategy for colon cancer immunotherapy.