Perforin-dependent killing of tumor cells by Vgamma1Vdelta1-bearing T-cells

In Vitro Expansion of Vδ1+ T Cells from Cord Blood by Using Artificial Antigen-Presenting Cells and Anti-CD3 Antibody

γδ T cells have the potential for adoptive immunotherapy since they respond to bacteria, viruses, and tumors. However, these cells represent a small fraction of the peripheral T-cell pool and require activation and proliferation for clinical benefits. In cord blood, there are some γδ T cells, which exhibit a naïve phenotype, and mostly include Vδ1+ T cells. In this study, we investigated the effect of CD3 signaling on cord blood γδ T-cell proliferation using K562-based artificial antigen presenting cells expressing costimulatory molecules. There were significantly more Vδ1+ T cells in the group stimulated with anti-CD3 antibody than in the group without. In cultured Vδ1+ T cells, DNAM-1 and NKG2D were highly expressed, but NKp30 and NKp44 showed low expression. Among various target cells, Vδ1+ T cells showed the highest cytotoxicity against U937 cells, but Daudi and Raji cells were not susceptible to Vδ1+ T cells. The major cytokines secreted by Vδ1+ T cells responding to U937 cells were Granzyme B, IFN-γ, and sFasL. Cytotoxicity by Vδ1+ T cells correlated with the expression level of PVR and Nectin of DNAM-1 ligands on the surface of target cells. Compared to Vδ2+ T cells in peripheral blood, cord blood Vδ1+ T cells showed varying cytotoxicity patterns depending on the target cells. Here, we determined the ideal conditions for culturing cord blood Vδ1+ T cells by observing that Vδ1+ T cells were more sensitive to CD3 signals than other subtypes of γδ T cells in cord blood. Cultured cord blood Vδ1+ T cells recognized target cells through activating receptors and secreted numerous cytotoxic cytokines. These results are useful for the development of tumor immunotherapy based on γδ T cells.

Differentiation and functional plasticity of gamma-delta (γδ) T cells under homeostatic and disease conditions

Gamma-delta (γδ) T cells are a heterogeneous population of immune cells, which constitute <5% of total T cells in mice lymphoid tissue and human peripheral blood. However, they comprise a higher proportion of T cells in the epithelial and mucosal barrier, where they perform immune functions, help in tissue repair, and maintaining homeostasis. These tissues resident γδ T cells possess properties of innate and adaptive immune cells which enables them to perform a variety of functions during homeostasis and disease. Emerging data suggest the involvement of γδ T cells during transplant rejection and survival. Interestingly, several functions of γδ T cells can be modulated through their interaction with other immune cells. This review provides an overview of development, differentiation plasticity into regulatory and effector phenotypes of γδ T cells during homeostasis and various diseases.

Suppression of R5-type of HIV-1 in CD4+ NKT cells by Vδ1+ T cells activated by flavonoid glycosides, hesperidin and linarin

We established transfectants expressing T cell receptors (TCRs) either for Vγ1 and Vδ1 (1C116) or for Vγ2 and Vδ2 (2C21) using the TCR-deficient Jurkat T cell line J.RT3-T3.5. The amount of IL-2 secreted from these γδ T cell clones accurately indicated TCR-dependent stimulation. Clone 2C21 was specifically stimulated by previously reported ligands for Vγ2Vδ2 (Vδ2)-TCR such as isopentenyl pyrophospate (IPP), ethylamine, or risedronate. In contrast, clone 1C116 was strongly stimulated through the Vγ1Vδ1 (Vδ1)-TCR by flavonoid glycosides such as hesperidin and linarin, having both rutinose at the A ring and methoxy (-OCH3) substitution at the B ring. Additionally, hesperidin and linarin showed stimulatory activity for peripheral blood mononuclear cell (PBMC)-derived T cells expressing Vδ1-TCR; these activated Vδ1⁺ T cells also secreted IL-5, IL-13, MIP-1α, MIP-1β and RANTES. Such PBMC-derived Vδ1⁺ T cells stimulated by hesperidin and linarin suppressed R5-HIV-1-NL(AD8) viral replication in CD4⁺ NKT cells in a dose-dependent manner. To the best of our knowledge, this is the first demonstration that flavonoid glycosides activate functional Vδ1⁺ T cells.

Association of γδ T Cell Compartment Size to Disease Activity and Response to Therapy in SLE

OBJECTIVE

Although γδT cells are widely recognized as pivotal elements in immune-mediated diseases, their role in the pathogenesis of SLE and therapeutic outcome remains under explored. The current study aims to characterize the γδT cell compartment in SLE and correlate its status to disease severity and response to therapy.

METHODS

Human peripheral blood-derived γδ T cells were isolated from 14 healthy volunteers and 22 SLE patients (before and after 4 and 12 weeks following the onset of glucocorticoids (GC), mycophenolatemofetil (MMF) orhydroxychloroquine (HCQ) treatment). The γδ T cells were characterized using flow cytometry. In addition, serum concentration of IFN-γ, TNF-α, IL-2, IL-4, IL-6, IL-10 and IL-17A was determined by cytometric bead array (CBA).

RESULTS

The SLEDAI scores dropped significantly following therapy in a subset of patients (responders-R) but not in some (non- responders-NR). Peripheral blood γδ T cells in general, and γ9+δ T cells and TNF-α/IL-17-secreting CD4-CD8-γδ T cell subsets in particular, were decreased in SLE compared to healthy controls. The numbers of the γδ T cell subsets reached levels similar to those of healthy controls following therapy in R but not in NR. Serum IL-6, IL-10 and IL-17 but not IFN-γ and TNF-α were significantly increased in SLE compared to the healthy controls and exhibited differential changes following therapy. In addition, inverse correlation was observed between SLEDAI scores and γδ T cell compartments, especially with TNF-α+γδT cells, TNF-α+γ9+δT cells and IL17+CD4-CD8-γδT cells subsets. Differential correlation patterns were also observed between serum cytokine levels and various γδ T cell compartments.

CONCLUSIONS

A strong association exists between γδ T cell compartments and SLE pathogenesis, disease severity and response to therapy.

V gamma 9V delta 2 T lymphocytes efficiently recognize and kill zoledronate-sensitized, imatinib-sensitive, and imatinib-resistant chronic myelogenous leukemia cells

Imatinib mesylate (imatinib), a competitive inhibitor of the BCR-ABL tyrosine kinase, is highly effective against chronic myelogenous leukemia (CML) cells. However, because 20-30% of patients affected by CML display either primary or secondary resistance to imatinib, intentional activation of Vgamma9Vdelta2 T cells by phosphoantigens or by agents that cause their accumulation within cells, such as zoledronate, may represent a promising strategy for the design of a novel and highly innovative immunotherapy capable to overcome imatinib resistance. In this study, we show that Vgamma9Vdelta2 T lymphocytes recognize, trogocytose, and efficiently kill imatinib-sensitive and -resistant CML cell lines pretreated with zoledronate. Vgamma9Vdelta2 T cell cytotoxicity was largely dependent on the granule exocytosis- and partly on TRAIL-mediated pathways, was TCR-mediated, and required isoprenoid biosynthesis by zoledronate-treated CML cells. Importantly, Vgamma9Vdelta2 T cells from patients with CML can be induced by zoledronate to develop antitumor activity against autologous and allogeneic zoledronate-treated leukemia cells, both in vitro and when transferred into immunodeficient mice in vivo. We conclude that intentional activation of Vgamma9Vdelta2 T cells by zoledronate may substantially increase their antileukemia activities and represent a novel strategy for CML immunotherapy.

Hepatosplenic gammadelta T-cell lymphoma after liver transplantation: report of the first 2 cases and review of the literature

Hepatosplenic gammadelta T-cell lymphoma is a rare lymphoproliferative disorder originating from natural killer-like Vdelta1-lymphocytes. This subtype has been described after different types of solid organ transplants. In this article, we describe the first 2 cases after liver transplantation. Both patients had thrombocytopenia with (hepato)splenomegaly but without peripheral lymphadenopathies and sinusoidal infiltration of the liver and spleen by monomorphic gammadelta-lymphocytes on pathological examination. The clinical and pathological findings, immunophenotypical profile, prognosis, and treatment are highlighted. In order to make an early diagnosis, physicians who take care of liver transplant recipients should be aware of the characteristic features of this posttransplant lymphoproliferative disorder. Therefore, a diagnostic algorithm is proposed.

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.

Immunomodulating role of bisphosphonates on human gamma delta T cells: an intriguing and promising aspect of their antitumour activity

Vgamma9Vdelta2 T cells have the ability to produce inflammatory cytokines involved in protective immunity against intracellular pathogens and tumours and to display strong cytolytic as well as bactericidal activities. This suggests a direct involvement of Vgamma9Vdelta2 T lymphocytes in immune control of cancer and infections. These observations have recently aided development of novel immunotherapeutic approaches aimed at Vgamma9Vdelta2 T cell activation. Nitrogen-containing bisphosphonates (N-BPs) play a crucial role in Vgamma9Vdelta2 T lymphocyte activation and in the acquisition of effector functions. The preliminary results of these innovative strategies are encouraging. Moreover, compelling evidence in the literature supports the hypothesis that the antitumour effect of bisphosphonates is exerted through direct as well as indirect mechanisms. An additional and not yet well explored mechanism by which N-BPs may display antineoplastic effect is related to their immunomodulatory properties. It is fascinating that N-BPs influence the immune system in various but interrelated ways, being able to enhance the innate and to promote the adaptive immune responses. For all these reasons, Vgamma9Vdelta2 T lymphocytes represent a particularly interesting target for immunotherapeutic protocols based on N-BP administration. All these unexpected effects of N-BPs on the immune system have opened new and intriguing possibilities of therapeutic use for these drugs.

Increased Number of Cytotoxic CD3+CD28– γδ T Cells in Peripheral Blood of Patients with Cutaneous Malignant Melanoma

BACKGROUND

A rise of CD3+ TCRgammadelta+ CD28- T cells has previously been observed after an in vitro long-lasting activation or even during viral infection.

OBJECTIVE

The aim of this study was to investigate the expression of CD28 on lymphocytes bearing CD3/TCRgammadelta receptors in cancer, i.e. cutaneous melanoma.

METHODS

TCRgammadelta lymphocytes were analysed in 41 Caucasian melanoma patients and 39 healthy individuals by flow cytometry. Patients were stratified according to the American Joint Committee on Cancer (AJCC) clinical stage.

RESULTS

The number of circulating CD3+ TCRgammadelta+ T cells was significantly increased in both AJCC stages I-II and AJCC stage III patients compared with healthy individuals. This increase was mediated by an accumulation of the CD3+ TCRgammadelta+ CD28- T-cell subset, which expressed a high amount of perforin both in normal individuals and melanoma patients.

CONCLUSION

This work shows, for the first time, a rise of the cytotoxic CD3+ TCRgammadelta+ CD28- T-cell population in melanoma patients, which may be important in anticancer surveillance.

Human gammadelta T cells from G-CSF-mobilized donors retain strong tumoricidal activity and produce immunomodulatory cytokines after clinical-scale isolation

Human gammadelta T cells are a small fraction of T cells that have been shown to exert major histocompatibility (MHC)-unrestricted natural cytotoxicity against a variety of solid tumors and some subsets of leukemias and lymphomas. They are also involved in the immune response to certain bacterial, viral, and parasitic infections and expand significantly in CMV- or HSV-infected organ allografts. They are able to mediate antibody-dependent cytotoxicity and are not alloreactive, which makes them attractive candidates for cell-based immunotherapy. However, their frequency in peripheral blood is low and ex vivo expansion of gammadelta T cells is labor-extensive, does not always yield cells with full innate cytotoxic power, and has the potential for microbial contamination. Therefore, the authors developed a clinical-scale, automated cell purification method for the efficient enrichment of gammadelta T cells from leukapheresis products. Six leukapheresis products were purified for gammadelta T cells using a single-step immunomagnetic method. Purity and phenotype were assessed by flow cytometry. A standard Europium release assay was performed to determine the cytotoxic capacity of the cells. Cytokine production was measured using a multiplex sandwich immunoassay. The mean percentage of gammadelta T cells in the final product was 91%, with an average recovery of 63%. The cells showed a high co-expression of CD8, CD56, CD28, and CD11b/CD18. In some products an unusually high proportion of Vgamma9Vdelta1 T cells was found. The isolated cells were cytotoxic against the neuroblastoma cell line NB1691 and the erythroleukemic line K562 in vitro. They were able to produce a variety of immunomodulatory cytokines such as IFNgamma, TNFalpha, and MIP-1beta, but also GM-CSF and G-CSF when co-incubated in culture with and without various stimuli. In summary, the authors describe a rapid, automated, and efficient method for the large-scale enrichment of human gammadelta T cells. The cytotoxic properties of the cells were preserved. This method yields sufficient purified gammadelta T cells for use in adoptive immunotherapy as well as laboratory investigations and animal studies.

Fas-Fas ligand interactions are essential for the binding to and killing of activated macrophages by gamma delta T cells

Gammadelta T cells have a direct role in resolving the host immune response to infection by eliminating populations of activated macrophages. Macrophage reactivity resides within the Vgamma1/Vdelta6.3 subset of gammadelta T cells, which have the ability to kill activated macrophages following infection with Listeria monocytogenes (Lm). However, it is not known how gammadelta T cell macrophage cytocidal activity is regulated, or what effector mechanisms gammadelta T cells use to kill activated macrophages. Using a macrophage-T cell coculture system in which peritoneal macrophages from naive or Lm-infected TCRdelta-/- mice were incubated with splenocytes from wild-type and Fas ligand (FasL)-deficient mice (gld), the ability of Vgamma1 T cells to bind macrophages was shown to be dependent upon Fas-FasL interactions. Combinations of anti-TCR and FasL Abs completely abolished binding to and killing of activated macrophages by Vgamma1 T cells. In addition, confocal microscopy showed that Fas and the TCR colocalized on Vgamma1 T cells at points of contact with macrophages. Collectively, these studies identify an accessory or coreceptor-like function for Fas-FasL that is essential for the interaction of Vgamma1 T cells with activated macrophages and their elimination during the resolution stage of pathogen-induced immune responses.