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Interactions between natural killer (NK) cells and dendritic cells (DC) affect maturation and function of both cell populations, including NK cell killing of DC (editing), which is important for controlling the quality of immune responses. We also know that antigen-stimulated Vγ2Vδ2 T cells co-stimulate NK cells via 4-1BB to enhance the killing of tumour cell lines but we do not know what regulates 4-1BB expression or whether other NK effector functions including DC killing, might also be influenced by NK-γδ T-cell cross-talk. Here we show that antigen-stimulated γδ T cells co-stimulate NK cells through inducible T-cell co-stimulator (ICOS)- ICOS ligand (ICOSL) and this signal increases NK cell killing of autologous DC. Effects of NK-γδ T-cell co-culture, which could be reproduced with soluble ICOS-Fc fusion protein, included increased CD69 and 4-1BB expression, interferon-γ, tumour necrosis factor-α, macrophage inflammatory protein-1β, I-309, RANTES and sFas ligand production, as well as elevated mRNA levels for co-stimulatory receptors OX40 (TNFRSF4) and GITR (TNFRSF18). Hence, ICOS-ICOSL co-stimulation of NK by Vγ2Vδ2 T cells had broad effects on NK phenotype and effector functions. The NK-γδ T-cell cross-talk links innate and antigen-specific lymphocyte responses in the control of cytotoxic effector function and DC killing. [ABSTRACT FROM AUTHOR]

It has been widely reported that T cells are capable of influencing osteoclast formation and bone remodelling, yet relatively little is known of the reciprocal effects of osteoclasts for affecting T cell function and/or activity. In this study we investigated the effects of human osteoclasts on the function of γδ T cells, a subset of non-CD4 + T cells implicated in a variety of inflammatory disease states. γδ T cells and CD4 + T cells were isolated from peripheral blood of healthy volunteers and were co-cultured with autologous mature osteoclasts (generated by treatment with M-CSF and RANKL) before phenotypical and functional changes in the T cell populations were assessed. Macrophages, osteoclasts, and conditioned medium derived from macrophages or osteoclasts induced activation of γδ T cells, as determined by the expression of the early activation marker CD69. TNFα was a major mediator of this stimulatory effect on γδ T cells. Consistent with this stimulatory effect, osteoclasts augmented proliferation of IL-2-stimulated γδ T cells and also supported the survival of unstimulated γδ and CD4 + T cells, although these effects required co-culture with osteoclasts. Co-culture with osteoclasts also increased the proportion of γδ T cells producing IFNγ, but did not modulate IFNγ or IL-17 production by CD4 + T cells. We provide new insights into the in vitro interactions between human γδ T cells and osteoclasts/macrophages, and demonstrate that osteoclasts or their precursors are capable of influencing γδ T function both via the release of soluble factors and also through direct cell–cell interactions. [ABSTRACT FROM AUTHOR]

Systematic evaluation of the role of γδT cells during the Schistosoma japonicum infection has not been reported, despite the fact that γδT cells contribute to many infectious diseases in innate immunity. Therefore, the aim of this study was to observe the properties of γδT cells in the liver of C57 BL/6 mice infected by S. japonicum. In this report, using immuno-fluorescent histological analysis, γδT cells were found around hepatic granulomatous. Moreover, the flow cytometry results revealed that the percentage of hepatic γδT cells increased significantly after S. japonicum infection. More interestingly, a subset of CD3−γδ TCR+ cells were found and markedly increased after infection. Furthermore, expression of activation markers ( CD25 and CD69) and cytokine profiles were detected in these hepatic CD3+γδ TCR+and CD3−γδ TCR+ cells. The significantly higher level of CD69, IL-4 and IL-17 were observed in CD3+γδ TCR+ cells after infection, suggesting that CD3+γδ TCR+ cells instead of CD3−γδ TCR+ cells might play a predominant role during the infection. Finally, our results indicated that the expression of NKG2D on CD3+γδ TCR+ cells was higher than that on CD3−γδ TCR+ cells. Collectively, γδT cells could play an important role in the liver of C57 BL/6 mouse during japonicum infection. [ABSTRACT FROM AUTHOR]

Spontaneous or medically induced reperfusion occurs in up to 70% of patients within 24 h after cerebral ischemia. Reperfusion of ischemic brain tissue can augment the inflammatory response that causes additional injury. Recently, T cells have been shown to be an essential part of the post-ischemic tissue damage, and especially IL-17 secreting T cells have been implicated in the pathogenesis of a variety of inflammatory reactions in the brain. After stroke, it seems that the innate γδ T cells are the main IL-17 producing cells and that the γδ T cell activation constitutes an early and mainly damaging immune response in stroke. Effector mechanism of γδ T cell derived IL-17 in the ischemic brain include the induction of metalloproteinases, proinflammatory cytokines and neutrophil attracting chemokines, leading to a further amplification of the detrimental inflammatory response. In this review, we will give an overview on the concepts of γδ T cells and IL-17 in stroke pathophysiology and on their potential importance for human disease conditions. [ABSTRACT FROM AUTHOR]

γδ T cells represent a major T cell population in epithelial tissues, such as skin, intestine, and lung, where they function in maintenance of the epithelium and provide a crucial first line defense against environmental and pathogenic insults. Despite their importance, the molecular mechanisms directing their activation and function have remained elusive. Epithelial-resident γδ T cells function through constant communication with neighboring cells, either via direct cell-to-cell contact or cell-to-matrix interactions. These intimate relationships allow γδ T cells to facilitate the maintenance of epithelial homeostasis, tissue repair following injury, inflammation, and protection from malignancy. Recent studies have identified a number of molecules involved in these complex interactions, under both homeostatic conditions, as well as following perturbation of these barrier tissues. These interactions are crucial to the timely production of cytokines, chemokines, growth factors, and extracellular matrix proteins for restoration of homeostasis. In this review, we discuss recent advances in understanding the mechanisms directing epithelial-T cell crosstalk and the distinct roles played by individual receptor-ligand pairs of cell surface molecules in this process. [ABSTRACT FROM AUTHOR]

γδ T cells are exported from the thymus as innate-like lymphocytes that can immediately respond to antigens. In the thymus, γδ T cells diverge into functionally distinct lineages. It is not known whether γδ T cells differentiate into regulatory cells that express Foxp3, which is an essential transcription factor for CD4 + regulatory T cells. In this study, we analyzed CD25 + immature thymocytes that give rise to both αβ and γδ thymocytes. These precursor cells have the potential to differentiate into Foxp3 + γδ T cells on a stromal cell line, TSt4-Dll1. Development of Foxp3 + γδ thymocytes in this culture was dependent on IL-2. IL-2 stimulation induced Id3, Egr1, and Egr3 expression in CD25 + immature thymocytes, suggesting that it could activate signaling molecules that are downstream of TCR signaling. The induction of Foxp3 in precursor γδ T cells suggested that IL-2 could activate the Foxp3 gene early in thymocyte development. [ABSTRACT FROM AUTHOR]

Pyrophosphorylated metabolites of isoprenoid-biosynthesis (phosphoantigens, PAgs) activate Vγ9Vδ2 T cells during infections and trigger antitumor activity. This activation depends on expression of butyrophilin 3 A1 ( BTN3A1) by antigen-presenting cells. This report defines the minimal genetic requirements for activation of Vγ9Vδ2 T cells by PAgs and mAb 20.1. We compared PAg-presentation by BTN3A1-transduced CHO hamster cells with that of CHO cells containing the complete human chromosome 6 (Chr6). BTN3A1 expression alone was sufficient for activation of Vγ9Vδ2 T-cell receptor transductants by mAb 20.1., while activation by PAgs also required the presence of Chr6. We take this finding as evidence that gene(s) on Chr6 in addition to BTN3A1 are mandatory for PAg-mediated activation of Vγ9Vδ2 T cells. This observation is important for the design of animal models for PAg-mediated immune responses and provokes speculations about the analogy between genes controlling PAg presentation and MHC-localized genes controlling peptide-antigen presentation. [ABSTRACT FROM AUTHOR]

A 70-year-old man presented with papular skin lesions and was diagnosed with Epstein- Barr virus ( EBV)-associated T-cell lymphoproliferative disorder (T- LPD). The patient showed infiltration of a large number of EBV-encoded RNA-positive T cells in the skin and lung, presence of EBV load in the peripheral blood, and expansion of clonal EBV-infected γδ T cells and CD8+ T cells in the blood and skin, as assessed by EBV-terminal repeat Southern blot, T-cell receptor polymerase chain reaction and flow cytometric analyses. In the Japanese or East Asian fatal cases of EBV-associated T/natural killer ( NK)- LPD, there are two peaks in age at death, approximately 20 years and 60 years. The former age group is associated with chronic active EBV infection ( CAEBV), and the latter group typically suffers from extranodal NK/ T-cell lymphoma. Our case is characterized not only by the unique skin and lung manifestations but also the late onset age of the disease, indicating that the skin manifestation of CAEBV can be seen even in elderly patients. [ABSTRACT FROM AUTHOR]

Inducible Treg (iTreg) cells generated from Ag-stimulated naïve CD4+ T cells in the periphery play an important role in regulating immune responses. TGF-β is a key cytokine that promotes this conversion process; however, how this process is regulated in vivo remains unclear. Here, we report that γδ T cells play a crucial role in controlling iTreg generation and suppressor function. Ag-induced iTreg generation was significantly enhanced in C57BL/6 mice in the absence of γδ T cells. Inhibition of iTreg conversion was mediated by IFN-γ produced by activated γδ T cells but not by activated CD4+ T cells. BM chimera experiments further confirmed γδ-derived IFN-γ-dependent mechanism in regulating iTreg generation in vivo. Lastly, human peripheral blood γδ T cells also interfere with iTreg conversion via IFN-γ. Our results suggest a novel function of γδ T cells in limiting the generation of iTreg cells, potentially balancing immunity and tolerance. [ABSTRACT FROM AUTHOR]

Abstract: Background: IL-17-producing CD4+ T (Th17) cells and their cytokines, IL-17A and IL-22, are deeply involved in the pathogenesis of psoriasis by stimulating epidermal keratinocytes to proliferate and to produce cytokines/chemokines and vascular endothelial growth factor (VEGF)-A. Plasmacytoid dendritic cells (pDCs), infiltrating in psoriatic lesions, are known to exacerbate the Th17-mediated pathogenesis of psoriasis. Objective: To address the initiative role of VEGF-A in the development of psoriasis and the pDC accumulation. Methods: Numerical changes and VEGF receptor 1 (VEGFR1) and VEGFR2 expressions were investigated in skin-infiltrating T cells and pDCs of K14-VEGF-A transgenic (Tg) and wild type (WT) mice. The chemotactic properties of VEGF-A for purified splenic pDCs were also evaluated by real-time chemotaxis assay. Results: By flow cytometry and immunohistochemistry, we observed that the number of dermal IL-17A+ γδ T cells, but not CD4+ T cells, was increased in VEGF-A Tg mice, suggesting that the main source of IL-17A was γδ T cells. Moreover, we identified pDCs as 440c+ cells by immunohistochemistry and as PDCA-1+B220+ cells by flow cytometry, and found that pDCs infiltrated at a higher frequency in VEGF-A Tg than WT mice. pDCs, but not γδ T cells, isolated from the skin expressed VEGFR1 and VEGFR2. Freshly isolated splenic pDCs expressed both receptors after 48-h cultivation. pDCs did not produce cytokines in response to VEGF-A, however, they had a strong velocity of chemotaxis toward VEGF-A at a comparable level to chemerin. Conclusions: These findings suggest that VEGF-A functions as not only a downstream enhancer but also an upstream initiator by chemoattracting pDCs in psoriatic lesions. [Copyright &y& Elsevier]

Highlights: [•] A novel chicken SLAMF4 specific mab is described. [•] SLAMF4 interacts with SLAMF2. [•] SLAMF4 is expressed on subpopulations of CD8+ αβ and γδ T cells. [•] SLAMF4 is found on a minor B cell population, on NK cells, monocytes and thrombocytes. [•] SLAMF4 expression levels differentiate several T cell subsets. [Copyright &y& Elsevier]

Ischemia reperfusion (IR) injury is a major issue in cardiac transplantation, and inflammatory processes play a major role in myocardial IR injury. Long pentraxin-3 (PTX3) is a member of a phylogenetically conserved group of acute-phase reactants that are involved in inflammation and innate immunity. In our study, hearts of C57Bl/6 mice were flushed and stored in cold Bretschneider solution for 8 h and then transplanted into syngeneic recipient. We found that both mRNA and protein levels of PTX3 were increased following myocardial IR injury; neutralizing antibody against PTX3 aggravated cardiomyocyte apoptosis and recruitment of neutrophils and macrophages. Troponin T (TnT) production on 24 h after myocardial IR injury was reduced by exogenous PTX3 administration and increased by PTX3 neutralization in comparison with control. Cardiac output at 60 mmHg of afterload pressure was also increased in hearts with exogenous PTX3 administration and decreased with PTX3 neutralization (PTX3: 58.4 ± 7.4 ml/min; Control: 24.5 ± 3.8 ml/min; Anti-PTX3: 11.6 ± 1.7 ml/min; P < 0.05). Furthermore, PTX3 restricted expansion of γδ T cell that was the major source of IL-17A and down-regulated expression of IL-23 and IL-17A. In conclusion, PTX3 played a protective role in cardiomyocyte IR injury. PTX3 ameliorated cardiomyocyte apoptosis and infiltration of neutrophil and macrophage and then improved hemodynamic performance. This was associated with restricted γδ T-cell expansion and decreased IL-23/IL-17A expression. [ABSTRACT FROM AUTHOR]

Background To investigate the characteristics of γδ T cells as well as the Vδ1+ and Vδ2+ subsets in the peripheral blood in liver allograft recipients. Methods Sixty-three liver transplant recipients were enrolled in this study: 26 cases with acute allograft rejection (Gr-AR), and 37 cases with stable allograft liver function (Gr-SF). The frequencies of γδ T cells, the Vδ1+ and Vδ2+ subsets, and interleukin (IL)-10-producing Vδ1+ γδ T cells in the peripheral blood were analyzed by flow cytometry. The relationship between liver function parameters and the Vδ1+/Vδ2+ ratio was analyzed. Results The frequency of the Vδ1+ subset and the Vδ1+/Vδ2+ ratio in Gr-SF was significantly higher than that in Gr-AR; in contrast, the frequency of the Vδ2+ subset in Gr-SF was markedly lower than that in Gr-AR. In addition, there was no significant difference in the frequency of γδ T cells between the Gr-AR and Gr-SF groups. Moreover, there was a significant negative correlation between the Vδ1+/Vδ2+ ratio with the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in Gr-AR. Conclusions Vδ1+ γδ T cells may have a potential role in maintaining stable graft liver function, and Vδ2+ γδ T cells may be associated with liver allograft rejection. The Vδ1+/Vδ2+ ratio could serve as a prognostic marker for acute rejection after liver transplantation. [ABSTRACT FROM AUTHOR]

Abstract: γδ T cells play important roles in innate immunity against tumors and infections. Inhibitory effect of dihydroartemisinin on growth of cancer cells has been found in recent years. In this study, we investigated the effect of dihydroartemisinin on human γδ T cell proliferation by MTT assay and killing activity against pancreatic cancer cells SW1990, BxPC-3 and PANC-1 by LDH release assay in vitro. Intracellular molecule alterations were verified by flow cytometry. The results suggested that appropriate concentration of dihydroartemisinin favored the expansion of γδ T cells and enhanced γδ T cell mediated killing activity against pancreatic cancer cells. Up-regulation of intracellular perforin, granzyme B expression and IFN-γ production may be the important mechanism of dihydroartemisinin on increased antitumor activity of γδ T cells. [Copyright &y& Elsevier]

Abstract: Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS). The etiology of MS is not well understood, but it is believed that myelin-specific CD4+ T cells play a central role in initiating and orchestrating CNS inflammation. In this scenario, CD4+ T cells, activated in the periphery, infiltrate the CNS, where, by secreting cytokines and chemokines, they start an inflammatory cascade. Given the central role of CD4+ T cells in CNS autoimmunity, they have been studied extensively, principally by using experimental autoimmune encephalomyelitis (EAE), an animal model of MS. In the late 1980s, CD4+ T cells, based on their cytokine production, were divided into two helper lineages, Th1 and Th2 cells. It was postulated that Th1 cells, which produce IFN-γ, mediate inflammation of the CNS in MS/EAE, while Th2 cells, which produce IL-4, have a beneficial effect in disease, because of their antagonistic effect on Th1 cells. The Th1/Th2 paradigm remained the prevailing view of MS/EAE pathogenesis until 2005, when a new lineage, Th17, was discovered. In a relatively short period of time it became apparent that Th17 cells, named after their hallmark cytokine, IL-17A, play a crucial role in many inflammatory diseases, including EAE, and likely in MS as well. The Th17 paradigm developed rapidly, initiating the debate of whether Th1 cells contribute to EAE/MS pathogenesis at all, or if they might even have a protective role due to their antagonistic effects on Th17 cells. Numerous findings support the view that Th17 cells play an essential role in autoimmune CNS inflammation, perhaps mainly in the initial phases of disease. Th1 cells likely contribute to pathogenesis, with their role possibly more pronounced later in disease. Hence, the current view on the role of Th cells in MS/EAE pathogenesis can be called the Th17/Th1 paradigm. It is certain that Th17 cells will continue to be the focus of intense investigation aimed at elucidating the pathogenesis of CNS autoimmunity. [Copyright &y& Elsevier]

Objective To evaluate the state of oral tolerance and its therapeutic role in mice with dextran sulfate sodium ( DSS)-induced colitis. Methods Delayed-type hypersensitivity ( DTH) was determined 7 and 14 days after DSS-induced colitis and control mice. Disease activity index ( DAI) score and colonic histopathological score were measured 7 days after colonic extracted protein ( CEP) or bovine serum albumin ( BSA) (control) was administrated, with the evaluation of Th1-Th2 balance in the spleen, Peyer's patch and γδ T cells in intraepithelial lymphocytes and lamina proper lymphocytes in the intestine. Results After fed with 250 μg ovalbumin oral tolerance was induced in 7 days in both DSS-induced colitis and control mice, while oral tolerance persisted in the control mice but vanished in DSS-induced colitis 14 days after ovalbumin challenge. DAI and colonic histopathological scores were decreased significantly after the ingestion of CEP (controlled by BSA) in DSS-induced colitis with significant reduction of Th1 and the ratio of Th1 to Th2 in Peyer's patch as well as the γδ T cells in lamina proper lymphocytes in the intestine. No significant difference in Th1-Th2 balance in the spleen and γδ T cells in intraepithelial lymphocytes in the intestine were observed. Conclusions There is a defect in oral tolerance at day 7 in DSS-induced colitis. If taken orally, CEP may have a protective role in DSS-induced colitis, which may be related to the deflection from Th1 to Th2 in Peyer's patch and the reduction of γδ T cells in lamina proper lymphocytes in the intestine. [ABSTRACT FROM AUTHOR]

T cells employ a cell surface heterodimeric molecule, the T cell receptor (TCR), to recognize specific antigens (Ags) presented by major histocompatibility complex (MHC) molecules and carry out adaptive immune responses. Most T cells possess a TCR with an α and a β chain. However, a TCR constituted by a γ and a δ chain has been described, defining a novel subset of T cells. γδ TCRs specific for a wide variety of ligands, including bacterial phosphoantigens, nonclassical MHC-I molecules and unprocessed proteins, have been found, greatly expanding the horizons of T cell immune recognition. This review aims to provide background in γδ T cell history and function in mouse and man, as well as to provide a critical view of some of the latest developments on this still enigmatic class of immune cells. [ABSTRACT FROM AUTHOR]

T-cell malignancies are often aggressive and associated with poor prognoses. Adoptive cell therapy has recently shown promise as a new line of therapy for patients with hematological malignancies. However, there are currently challenges in applying adoptive cell therapy to T-cell malignancies. Various approaches have been examined in preclinical and clinical studies to overcome these obstacles. This review aims to provide an overview of the recent progress on adoptive cell therapy for T-cell malignancies. The benefits and drawbacks of different types of adoptive cell therapy are discussed. The potential advantages and current applications of innate immune cell-based adoptive cell therapy for T cell malignancies are emphasized.

The authors discuss the controversy on the relative contributions of the natural killer receptors (NKRs) and γδ T-cell receptor (TCR) to tumor-cell which targets by γδ T cells. They mention that key characteristic shared by the two subsets of lymphocyte is the expression of receptors encoded with germline depicted in natural killer (NK) cells. They state that γδ cells depend on the TCRγδ for the perception of pathogen-related molecular patterns.

The aim of this study was to explore whether desensitization to the occurrence of the acute-phase response (APR) in patients previously treated with amino-bisphosphonates (N-BPs) is due to a long-lasting reduction in the number of circulating γδ T cells. Circulating lymphocyte subpopulation counts were obtained from 63 patients with postmenopausal or senile osteoporosis at baseline and after 2 days and 12 months of the first intravenous (IV) 5 mg zoledronic acid (ZOL) infusion. At baseline both the proportion and absolute number of circulating γδ T cells were significantly higher in patients who had never used N-BPs vs. previous users, either oral or IV. A typical APR was observed in none of the patients given IV ZOL a year earlier, in 6 (22 %) of the patients previously treated with oral N-BPs, and in 13 (57 %) of the patients naive to any N-BP treatment. In patients naive to N-BPs, a significant reduction in both total lymphocytes and their subsets was observed 2 days after ZOL infusion; all these changes returned to baseline values 1 year later with the exception of γδ T cells, which remained significantly lower in terms of both proportion and absolute number. These results indicate for the first time that both IV and oral N-BP treatments are associated with a long-lasting decrease in circulating γδ T cells, and this may explain the lower incidence of APR in patients previously exposed to N-BPs. Other clinical implications of this sustained effect of N-BPs on immune-regulatory cells might be important. [ABSTRACT FROM AUTHOR]

We previously showed that formation of pulmonary granulomas in mice in response to a mycobacterial glycolipid, trehalose 6,6′-dimycolate (TDM) is due to the action of TNF-α and not of IFN-γ. However, the mechanisms of formation and maintenance of pulmonary granulomas are not yet clear. The purpose of the present study is to evaluate the mechanisms of granuloma formation by TDM at the early phase. Histological analysis showed that inflammatory cells infiltrated the murine pulmonary interstitium on day 2 after an intravenous injection with TDM as a w/o/w emulsion. Clear granuloma formation was observed on day 7 after the injection. The mRNA expression of IL-17, IFN-γ and macrophage inflammatory protein 2 was found in lung mononuclear cells at the day after TDM injection. The major IL-17-producing cells were T-cell receptor (TCR) γδ T cells expressing Vγ6. In mice depleted of γδ T cells by treatment with anti-TCR γδ monoclonal antibody, the number of TDM-induced granuloma was decreased, but the size of granuloma was not affected. Our results suggest that the mycobacterial glycolipid TDM causes activation of IL-17-producing TCR γδ T cells and stimulates chemotaxis of inflammatory cells including neutrophils in to lung. [ABSTRACT FROM AUTHOR]

Abstract: Various subsets of T-cell receptor (TCR) γδ+ T cells expressing distinct TCR-Vγ chains are found in many different anatomical locations. These TCR γδ+ T cells perform multiple functions as an essential part of the immune system. In particular, protection against malaria infection by TCR γδ+ T cells is of special interest. In the present study, we confirmed that the Vγ7+ γδ T cells, which are an unconventional subset usually localized within the intestine, are recruited to the liver and spleen at the late stage of malaria infection, and contribute to protection against malaria infection via a multifunctional approach in apoptosis inhibitor-deficient mice. [Copyright &y& Elsevier]

The inflammatory cytokine IL-17 plays a critical role in immunity to infection and is involved in the inflammatory pathology associated with certain autoimmune diseases, such as psoriasis and rheumatoid arthritis. While CD4+ and CD8+ T cells are important sources of this cytokine, recent evidence has suggested that γδ T cells and a number of families of innate lymphoid cells ( ILCs) can secrete IL-17 and related cytokines. The production of IL-17 by γδ T cells appears to be largely independent of T-cell receptor act-ivation and is promoted through cytokine signalling, in particular by IL-23 in combination with IL-1β or IL-18. Therefore IL-17-secreting γδ T cells can be categorised as a family of cells similar to innate-like lymphoid cells. IL-17-secreting γδ T cells function as a part of mucosal defence against infection, with most studies to date focusing on their response to bacterial pathogens. γδ T cells also play a pathological role in certain autoimmune diseases, where they provide an early source of IL-17 and IL-21, which initiate responses mediated by conventional IL-17-secreting CD4+ T cells ( Th17 cells). ILCs lack an antigen receptor or other linage markers, and ILC subsets that express the transcriptional factor RORγt have been found to secrete IL-17. Evidence is emerging that these newly recognised sources of IL-17 play both pathological and protective roles in inflammatory diseases as discussed in this article. [ABSTRACT FROM AUTHOR]

In T cells, two members of the Dok family, Dok-1 and Dok-2, are predominantly expressed. Recent evidence suggests that they play a negative role in T-cell signaling. In order to define whether Dok proteins regulate T-cell development, we have generated transgenic mice overexpressing Dok-1 in thymocytes and peripheral T cells. We show that overexpression of Dok-1 retards the transition from the CD4− CD8− to CD4+ CD8+ stage. Moreover, there is a specific expansion of PLZF-expressing Vγ1.1+ Vδ6.3+ T cells. This subset of γδ T cells acquires innate characteristics including rapid IL-4 production following stimulation and requiring SLAM-associated adaptor protein ( SAP) for their development. Moreover, Dok-1 overexpression promotes the generation of an innate-like CD8+ T-cell population that expresses Eomesodermin. Altogether, these findings identify a novel role for Dok-1 in the regulation of thymic differentiation and in particular, in the development of PLZF+ γδ T cells. [ABSTRACT FROM AUTHOR]

Abstract: Bovine tuberculosis is a disease of increasing incidence in the UK causing major economic losses and with significant impact on bovine and, potentially human health: the causative agent Mycobacterium bovis is a zoonotic pathogen. Neonatal vaccination with the attenuated M. bovis Bacille Calmette Guerin (BCG) vaccine confers a significant degree of protection in cattle, and is a widely used control strategy for human TB. The adaptive immune system is relatively immature in neonates and increased numbers of innate effector cells present in young animals and human infants may compensate for this, enabling effective immune responses to vaccination. Natural killer cells and subsets of γδ TCR+ T lymphocytes secrete high levels of interferon gamma and can interact with antigen presenting cells to promote both innate and adaptive immune responses. These cell populations may be pivotal in determining immune bias following neonatal vaccination with BCG. [Copyright &y& Elsevier]

Abstract: Although experimental autoimmune encephalomyelitis (EAE) is limited in its potency to reproduce the entirety of clinical and histopathologic features of multiple sclerosis (MS), this model has been successfully used to prove that MS like autoimmunity in the CNS is orchestrated by autoantigen specific T cells. EAE was also very useful to refute the idea that IFN-γ producing T helper type 1 (Th1) cells were the sole players within the pathogenic T cell response. Rather, “new” T cell lineages such as IL-17 producing Th17 cells or IL-9 producing Th9 cells have been first discovered in the context of EAE. Here, we will summarize new concepts of early and late T cell plasticity and the cytokine network that shapes T helper cell responses and lesion development in CNS specific autoimmunity. [Copyright &y& Elsevier]

Vγ9Vδ2 T cells play a crucial role in the antitumoral immune response through cytokine production and cytotoxicity. Although the expression of the immunomodulatory molecule HLA-G has been found in diverse tumors, its impact on Vγ9Vδ2 T-cell functions remains unknown. Here we showed that soluble HLA-G inhibits Vγ9Vδ2 T-cell proliferation without inducing apoptosis. Moreover, soluble HLA-G inhibited the Vγ9Vδ2 T-cell production of IFN-γ induced by phosphoantigen stimulation. The reduction in Vγ9Vδ2 T-cell IFN-γ production was also induced by membrane-bound or soluble HLA-G expressed by tumor cell lines. Finally, primary tumor cells inhibited Vγ9Vδ2 T-cell proliferation and IFN-γ production through HLA-G. In this context, HLA-G impaired Vγ9Vδ2 T-cell cytotoxicity by interacting with ILT2 inhibitory receptor. These data demonstrate that HLA-G inhibits the anti-tumoral functions of Vγ9Vδ2 T cells and imply that treatments targeting HLA-G could optimize Vγ9Vδ2 T-cell-mediated immunotherapy of cancer. [ABSTRACT FROM AUTHOR]

Human Vγ2 Vδ2-bearing T cells have recently received much attention in cancer immunotherapy. In this study, we conducted a phase I/II clinical trial of the adoptive transfer of γδ T cells to patients with advanced renal cell carcinoma. Eleven patients who had undergone nephrectomy and had lung metastasis were enrolled. Peripheral blood γδ T cells obtained from the patients were stimulated ex vivo with 2-methyl-3-butenyl-1-pyrophosphate (2M3B1PP), a synthetic pyrophosphomonoester antigen, and transferred in combination with zoledronic acid (Zol) and teceleukin (recombinant human interleukin-2). Expanded γδ T cells exhibited potent cytotoxic activity against tumor cells in vitro, and the proportion of peripheral blood γδ T cells among CD3 cells typically peaked three to 5 days after transfer. Tumor doubling time was prolonged in all 11 patients, and the best overall responses were 1 CR, 5 SD, and 5 PD, as defined based on Response Evaluation Criteria in Solid Tumors (RECIST). Although ten patients developed adverse reactions of grade ≥3, they were likely to have been the result of the concomitant infusion of Zol and IL-2, and most symptoms swiftly reverted to normal during the course of treatment. In conclusion, this clinical trial demonstrated that our regimen for the adoptive transfer of γδ T cells in combination with Zol and IL-2 was well tolerated and that objective clinical responses could be achieved in some patients with advanced renal cell carcinoma. [ABSTRACT FROM AUTHOR]

The regulation of IL-17A and IL-22 production differs between human and murine γδ T cells. We find that human γδ T cells expressing Vγ2Vδ2 T cell receptors are peripherally polarized to produce IL-17A or IL-22, much like CD4 αβ Th17 T cells. This requires IL-6, IL-1β, and TGF-β, whereas expansion and maintenance requires IL-23, IL-1β, and TGF-β. In contrast, IL-17A and IL-22 production by murine γδ T cells is innately programmed during thymic ontogeny but requires IL-23 and IL-1β for maintenance. Murine γδ cells producing IL-17A and IL-22 play important roles in microbial, autoimmune, and inflammatory responses. However, the roles played by human IL-17A- and IL-22-producing γδ T cells are less clear but are also likely to be important. These observations highlight differences between humans and murine γδ T cells and underscore the importance of IL-17A- and IL-22-producing γδ T cells. [ABSTRACT FROM AUTHOR]

Abstract: Carp kidney leukocytes co-cultured with a supporting cell layer resulted in the rapid proliferation of various types of leukocytes including immature leukocytes. Expressions of marker genes for multiple blood cell lineages were observed in the primary culture. However, after several passages, the proliferating cells expressed only T cell and macrophage marker genes. Further RT-PCR analysis revealed that the proliferating cells expressed TCR constant regions (Cα, Cβ, Cγ, Cδ), CD3γ/δ and CD4 (CD4L-1), but did not express CD8α and CD8β. Additionally, in situ hybridization analysis showed that the majority of proliferating cells expressed Cα, Cβ, Cγ, Cδ and CD4. Moreover, 5′-RACE sequences of TCR variable regions (Vα, Vβ, Vγ, Vδ) revealed that the proliferating cells contained a polyclonal T cell repertoire, and most of the Vα and Vβ sequences were functional, but the Vγ and Vδ sequences were non-functional with frame shifts and stop codons. Taken together, these results indicate that the proliferating cells after serial passages predominantly contained CD4+ CD8− αβT cells that simultaneously co-expressed non-functional γδTCR. To obtain CD4+ αβT cell (helper T cell) clones, single cells were picked up from the bulk culture, seeded into each well of 96-well plates and cultured in the presence of supporting cells and conditioned media. T cell colonies formed from single cells after 2–3 weeks. These colony cells expressed Cα, Cβ, Cδ and CD4, and weakly expressed Cγ, but did not express CD8α, CD8β and CD4L-2. Taken together, these results indicate that these clonal T cells resemble a subpopulation of mammalian CD4+ helper T cells. [Copyright &y& Elsevier]

The mucosal immune system is constantly exposed to a wide range of commensal and potentially pathogenic microbial species. Chronic exposure to foreign organisms makes generation of an appropriate immune response critical in maintaining a balance between elimination of harmful pathogens, peaceful coexistence with commensals, and prevention of autoimmunity. Intestinal intraepithelial lymphocytes provide a first line of defense at this extensive barrier with the outside world, and as such, understanding their role in immunity is critical. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) and colorectal carcinoma with hepatic metastases (mCRC) are cancers with poor prognosis and limited therapeutic options. New approaches are needed and adoptive immunotherapy with Vγ9Vδ2 T lymphocytes represents an attractive strategy. Indeed, Vγ9Vδ2 T cells were shown to exhibit efficient lytic activity against various human tumor cell lines, and in vitro Vγ9Vδ2 T expansion protocol based on single phosphoantigen stimulation could be easily performed for healthy donors. However, a low proliferative response of Vγ9Vδ2 T cells was observed in about half of the cancer patients, leading to an important limitation in the development of Vγ9Vδ2 T cell-based immunotherapy. Here, for the first time in the context of cancer patients, Vγ9Vδ2 T cell expansions were performed by co-culturing peripheral blood mononuclear cell (PBMCs) with autologous dendritic cells (DCs) pretreated with aminobisphosphonate zoledronate. For patients not responding to the conventional culture protocol, co-culture of PBMC with zoledronate-pretreated DCs induced strong cell expansion and allowed reaching a minimal rate of purity of 70% of Vγ9Vδ2 T cells. The potent immunostimulatory activity of zoledronate-treated DCs was associated with higher amount of isopentenyl pyrophosphate (IPP) in the culture and was correlated with better ability to activate Vγ9Vδ2 T cells as measured by IFN-γ production. Moreover, we demonstrated that the cytotoxic level of Vγ9Vδ2 T cells against freshly autologous tumor cells isolated from patients could be significantly increased by pretreating the tumor cells with zoledronate. Thus, this method of generating Vγ9Vδ2 T cells leads eligible for Vγ9Vδ2 T cell adoptive immunotherapy the HCC and mCRC patients. [ABSTRACT FROM AUTHOR]

The study of intestinal intraepithelial γδ lymphocytes has been hindered by the difficulty of isolating a population of pure cells representative of their in vivo phenotype and function. Here, we describe a procedure for the purification of small intestinal intraepithelial γδ T lymphocytes in BALB/c mice, including extraction and purification of intraepithelial lymphocytes (IELs) followed by separation of γδ T cells from IELs by magnetic activated cell sorting (MACS). The small intestinal IEL isolation protocol reported here is a less time-consuming with high purity and high yields. One-step Percoll purification of IELs using a 40%-70% discontinuous Percoll gradient is less laborious yet sufficient to get exact profiles during phenotypic analysis of cell subsets. IELs obtained after two-step Percoll centrifugation using 30% Percoll, followed by a 40%-70% discontinuous Percoll gradient, are fit to purify γδ T cells by MACS. Small intestinal IELs produce much more IFN-γ and TGF-β1 than sorted γδ T cells upon stimulation with plate-bound anti-CD3ℇ mAb. γδ T cells secret moderate amounts of TGF-β1 and minimal amounts of IFN-γ. Purification of γδ T cells is helpful in investigating the phenotype and function of intestinal mucosal γδ T cells. [ABSTRACT FROM AUTHOR]

The signal of the IL-7R and signal transducers and activators of transcription (STAT) 5 plays an essential role in γδ T-cell development by inducing V–J recombination in the TCRγ locus. Previously, we have shown that STAT5 binds to the Jγ promoters and controls chromatin accessibility by histone acetylation. However, little is known on control mechanism of Vγ region by the IL-7R. To elucidate the regulation by STAT5, we first analyzed the chromatin status of Vγ region in primary thymocytes. The levels of histone H3 acetylation are high at Vγ5, HsA element and Vγ2 in Rag2−/− thymocytes but low in IL-7R α-chain (IL-7Rα)-deficient early thymocytes, suggesting that IL-7R signaling controls the accessibility of the Vγ region. In addition, high levels of histone H3 acetylation and germ line transcription were induced at Vγ5 and HsA by cytokine and STAT5 in cytokine-dependent Ba/F3 and other hematopoietic cell lines. Importantly, the chromatin accessibility of Vγ5 gene is increased by cytokine signal. Furthermore, STAT5 was not recruited to a non-canonical STAT-binding motif in the endogenous chromatin of the Vγ5 promoter by cytokine stimulation, while STAT5 binds to a consensus motif in the HsA element. In accordance with this result, STAT5 does not directly activate the Vγ5 promoter by reporter assay. These results suggested that while STAT5 directly binds to HsA element and induces its histone acetylation, STAT5 indirectly activates the Vγ5 promoter. Thus, this study implies a potential role of STAT5 in accessibility control of Vγ region, especially at Vγ5 and HsA. [ABSTRACT FROM AUTHOR]

γδ T cells are important for the early control of West Nile virus (WNV) dissemination. Here, we investigated the role of γδ T cells in the regulation of CD4+ T-cell response following a WNV challenge. Splenic dendritic cells (DCs) of WNV-infected γδ T-cell-deficient (TCRδ−/−) mice displayed lower levels of CD40, CD80, CD86 and major histocompatibility complex (MHC) class II expression and interleukin-12 (IL-12) production than those of wild-type mice. Naïve DCs cocultured with WNV-infected γδ T cells showed enhanced levels of costimulatory molecules, MHC class II expression and IL-12 production. Further, coculture of CD4+ T cells from OT II transgenic mice with DCs of WNV-infected TCRδ−/− mice induced less interferon-γ (IFN-γ) and IL-2 production than with those of wild-type controls. Viral antigens were detected in WNV-infected γδ T cells.WNV infection or toll-like receptor (TLR) agonist treatment of γδ T cells induced the production of IFN-γ, tumor necrosis factor-α and IL-6, which are known to promote DC maturation. Nevertheless, the levels of TLRs 2, 3, 4 and 7 expression of WNV-infected γδ T cells were not different from those of noninfected cells. Overall, these data suggest that WNV-induced γδ T-cell activation promotes DC maturation and initiates CD4+ T-cell priming. [ABSTRACT FROM AUTHOR]

Bisphosphonates, especially nitrogen-containing bisphosphonates (N-BPs), are widely used to block bone destruction associated with bone metastasis because they are effective inhibitors of osteoclastmediated bone resorption. In addition to their antiresorptive activity, growing preclinical evidence shows that N-BPs have direct and indirect anti-tumor activities. Some of the anti-tumor activities of N-BPs are associated with human γδ T cells that are key players in the interface between innate and adaptive immunity. This review examines the molecular and cellular mechanisms through which N-BPs stimulate the expansion and anti-tumor activity of human γδ T cells, suggesting a new role for N-BPs in cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Substantial evidence has been accumulated to indicate that γδ T cells take part in type 2 immune responses. It is not yet clear, however, in what capacity. Apparently, γδ T cells themselves can not only take the function of follicular T helper (TH) cells in certain responses, but also can support responses that are dependent on classical help provided by αβ T cells. Furthermore, the γδ T cells engage as regulators of TH2 immunity. Here, we consider two mouse models that depend on type 2 immunity, non-specific airway hyperresponsiveness to methacholine after allergen inhalation challenge and the primary IgE response induced by alum-aided immunization, and examine the function of γδ T cells. In either case, γδ T cells regulate type 2 immunity through balanced enhancing and inhibitory influences. However, after airway allergen exposure, suppressive γδ T cells become dominant. The underlying mechanisms are discussed. [ABSTRACT FROM AUTHOR]

Although interleukin-17 (IL-17) has been reported to participate in the pathogenesis of infectious, autoimmune and allergic disorders, the precise role in allograft rejection remains uncertain. This study illustrates that IL-17 contributes to the pathogenesis of chronic allograft rejection. Utilizing a murine heterotopic heart transplant model system, IL-17-deficient recipient mice had decreased allograft inflammatory cell recruitment, decreased IL-6, MCP-1, and KC production, and reduced graft coronary artery disease (GCAD). Intragraft gamma delta (γδ) T cells appear to be the predominant source of IL-17 production. Therefore, IL-17 neutralization may provide a potential target for novel therapeutic treatment for cardiac allograft rejection. [ABSTRACT FROM AUTHOR]

Background aims Encouraging evidence of clinical benefits from cancer immunotherapy is beginning to accumulate in several clinical trials. Cancer immunotherapy is based on two main methods, active vaccination and cell-transfer therapy. The ex vivo expansion of T cells is required to monitor vaccine-induced antigen-specific T cells or prepare large numbers of reactive lymphocytes for adoptive transfer. Methods We examined the influence of culture medium on T-cell growth, cytotoxicity and phenotype after activation using immobilized anti-CD3 monoclonal antibody or Zoledronate stimulation. Peripheral blood mononuclear cells (PBMC) were cultured in RPMI, AIM-V or OpTmizer with or without autologous serum. Results When supplemented with sufficient serum, RPMI was a good culture medium for T-cell expansion following anti-CD3 stimulation. Addition of autologous serum to AIM-V or OpTmizer increased the numbers of cells obtained to a similar extent, but their phenotype and function were quite different. Activated T cells cultured with OpTmizer mediated greater cytotoxicity than any other culture. Regardless of the media used, the main population expanded after CD3 stimulation was CD3+ CD8+. While more CD3+ CD4+ T cells were induced in RPMI and AIM-V, more CD3- CD56+ cells and CD3+ CD56+ T cells were induced in OpTmizer. When cells were stimulated by Zoledronate for 14 days, approximately 7.2 times and 11.5 times more γδ T cells were obtained in OpTmizer than AIM-V or RPMI, respectively. Conclusions Successful immunotherapy depends on the selection of appropriate culture media to support efficient expansion of the type of T cell desired. [ABSTRACT FROM AUTHOR]

Almost all individuals diagnosed with glioblastoma multiforme (GBM) will die of their disease as no effective therapies exist. Clearly, novel approaches to this problem are needed. Unlike the adaptive αβ T cell-mediated immune response, which requires antigen processing and MHC-restricted peptide display by antigen-presenting cells, γδ T cells can broadly recognize and immediately respond to a variety of MHC-like stress-induced self antigens, many of which are expressed on human GBM cells. Until now, there has been little progress toward clinical application, although several investigators have recently published clinically approvable methods for large-scale ex vivo expansion of functional γδ T cells for therapeutic purposes. This review discusses the biology of γδ T cells with respect to innate immunotherapy of cancer with a focus on GBM, and explores graft engineering techniques in development for the therapeutic use of γδ T cells. [ABSTRACT FROM AUTHOR]