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Sample records for acquired t-cell mediated

  1. AKT-mediated enhanced aerobic glycolysis causes acquired radioresistance by human tumor cells

    International Nuclear Information System (INIS)

    Shimura, Tsutomu; Noma, Naoto; Sano, Yui; Ochiai, Yasushi; Oikawa, Toshiyuki; Fukumoto, Manabu; Kunugita, Naoki

    2014-01-01

    Background and purpose: Cellular radioresistance is a major impediment to effective radiotherapy. Here, we demonstrated that long-term exposure to fractionated radiation conferred acquired radioresistance to tumor cells due to AKT-mediated enhanced aerobic glycolysis. Material and methods: Two human tumor cell lines with acquired radioresistance were established by long-term exposure to fractionated radiation with 0.5 Gy of X-rays. Glucose uptake was inhibited using 2-deoxy-D-glucose, a non-metabolizable glucose analog. Aerobic glycolysis was assessed by measuring lactate concentrations. Cells were then used for assays of ROS generation, survival, and cell death as assessed by annexin V staining. Results: Enhanced aerobic glycolysis was shown by increased glucose transporter Glut1 expression and a high lactate production rate in acquired radioresistant cells compared with parental cells. Inhibiting the AKT pathway using the AKT inhibitor API-2 abrogated these phenomena. Moreover, we found that inhibiting glycolysis with 2-deoxy-D-glucose suppressed acquired tumor cell radioresistance. Conclusions: Long-term fractionated radiation confers acquired radioresistance to tumor cells by AKT-mediated alterations in their glucose metabolic pathway. Thus, tumor cell metabolic pathway is an attractive target to eliminate radioresistant cells and improve radiotherapy efficacy

  2. Fatty Acids, Lipid Mediators, and T-Cell Function

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    de Jong, Anja J.; Kloppenburg, Margreet; Toes, René E. M.; Ioan-Facsinay, Andreea

    2014-01-01

    Research toward the mechanisms underlying obesity-linked complications has intensified during the last years. As a consequence, it has become clear that metabolism and immunity are intimately linked. Free fatty acids and other lipids acquired in excess by current feeding patterns have been proposed to mediate this link due to their immune modulatory capacity. The functional differences between saturated and unsaturated fatty acids, in combination with their dietary intake are believed to modulate the outcome of immune responses. Moreover, unsaturated fatty acids can be oxidized in a tightly regulated and specific manner to generate either potent pro-inflammatory or pro-resolving lipid mediators. These oxidative derivatives of fatty acids have received detailed attention during the last years, as they have proven to have strong immune modulatory capacity, even in pM ranges. Both fatty acids and oxidized fatty acids have been studied especially in relation to macrophage and T-cells functions. In this review, we propose to focus on the effect of fatty acids and their oxidative derivatives on T-cells, as it is an active area of research during the past 5 years. The effect of fatty acids and their derivatives on activation and proliferation of T-cells, as well as the delicate balance between stimulation and lipotoxicity will be discussed. Moreover, the receptors involved in the interaction between free fatty acids and their derivatives with T-cells will be summarized. Finally, the mechanisms involved in modulation of T-cells by fatty acids will be addressed, including cellular signaling and metabolism of T-cells. The in vitro results will be placed in context of in vivo studies both in humans and mice. In this review, we summarize the latest findings on the immune modulatory function of lipids on T-cells and will point out novel directions for future research. PMID:25352844

  3. T cell responses in senior patients with community-acquired pneumonia related to disease severity.

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    Bian, Lu-Qin; Bi, Ying; Zhou, Shao-Wei; Chen, Zi-Dan; Wen, Jun; Shi, Jin; Mao, Ling; Wang, Ling

    2017-12-01

    Senior individuals older than 65 years of age are at a disproportionally higher risk of developing pneumonia. Impaired capacity to defend against airway infections may be one of the reasons. It is generally believed that weaker regulatory T cell responses may be beneficial to host defense against pathogens. In senior patients with community-acquired bacterial pneumonia, we investigated the frequencies and functions of regulatory T cells. Interestingly, we found that compared to age- and sex-matched healthy controls, senior pneumonia patients presented lower frequencies of Foxp3-expressing and Helios-expressing CD4 + T cells. The quantity of Foxp3 and Helios being expressed, measured by their mRNA transcription levels, was also lower in CD4 + T cells from pneumonia patients. Furthermore, following TCR and TGF-β stimulation, pneumonia patients presented impaired capacity to upregulate Foxp3 and Helios. Functional analyses revealed that CD4 + T cells from pneumonia patients secreted lower amounts of IL-10 and TGF-β, two cytokines critical to regulatory T cell-mediated suppression. Also, the expression of granzyme B and perforin, which were cytolytic molecules potentially utilized by regulatory T cells to mediate the elimination of antigen-presenting cells and effector T cells, were reduced in CD4 + CD25 + T cells from senior pneumonia patients. In addition, the CD4 + CD25 + T cells from senior pneumonia patients presented reduced capacity to suppress effector CD4 + and CD8 + T cell proliferation. Moreover, the value of pneumonia severity index was inversely correlated with several parameters of regulatory T cell function. Together, our results demonstrated that senior pneumonia patients presented a counterintuitive impairment in regulatory T cell responses that was associated with worse prognosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Possible neuroimmunomodulation therapy in T-cell-mediated oral diseases

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    Tsuyoshi Sato

    2015-01-01

    Full Text Available Introduction: Recurrent aphthous stomatitis and oral lichen planus are local chronic inflammatory diseases which are implicated in T cell-mediated immunity. According to the systematic review, there is insufficient evidence to support any specific treatment for T-cell mediated oral diseases. The hypothesis: In this paper, we propose a hypothesis that recurrent aphthous stomatitis and oral lichen planus can be treated with selective α7 subunit of nicotinic acetylcholine receptor (α7 -nAChR agonists. Our hypothesis is supported by the following two facts. First, the pathophysiological conditions, T h 1/T h 17 cell activation and autonomic nervous system dysfunction, are observed in T-cell mediated oral diseases as well as in T-cell mediated systemic diseases such as rheumatoid arthritis. Second, the cholinergic anti-inflammatory pathway is inhibited in systemic T-cell mediated chronic inflammatory diseases. On the other hand, treatment with α7 -nAChR agonists which activate the cholinergic anti-inflammatory pathway suppresses neuroinflammation via inhibition of T h 1/T h 17 responses in animal model of systemic T-cell mediated chronic inflammatory diseases. We thus expect that selective α7 -nAChR agonists will be effective for the treatment of T-cell mediated oral diseases. Evaluation of the hypothesis: To test our hypothesis, we need to develop in vivo mouse model of T-cell mediated oral diseases. To evaluate the therapeutic effect of a selective α7 -nAChR agonist, we choose ABT-107 because of its safety and tolerability. We believe that the selective α7 -nAChR agonist, especially ABT-107, may be a therapeutic drug to treat T-cell mediated oral diseases.

  5. Membrane-bound Dickkopf-1 in Foxp3+ regulatory T cells suppresses T-cell-mediated autoimmune colitis.

    Science.gov (United States)

    Chae, Wook-Jin; Park, Jong-Hyun; Henegariu, Octavian; Yilmaz, Saliha; Hao, Liming; Bothwell, Alfred L M

    2017-10-01

    Induction of tolerance is a key mechanism to maintain or to restore immunological homeostasis. Here we show that Foxp3 + regulatory T (Treg) cells use Dickkopf-1 (DKK-1) to regulate T-cell-mediated tolerance in the T-cell-mediated autoimmune colitis model. Treg cells from DKK-1 hypomorphic doubleridge mice failed to control CD4 + T-cell proliferation, resulting in CD4 T-cell-mediated autoimmune colitis. Thymus-derived Treg cells showed a robust expression of DKK-1 but not in naive or effector CD4 T cells. DKK-1 expression in Foxp3 + Treg cells was further increased upon T-cell receptor stimulation in vitro and in vivo. Interestingly, Foxp3 + Treg cells expressed DKK-1 in the cell membrane and the functional inhibition of DKK-1 using DKK-1 monoclonal antibody abrogated the suppressor function of Foxp3 + Treg cells. DKK-1 expression was dependent on de novo protein synthesis and regulated by the mitogen-activated protein kinase pathway but not by the canonical Wnt pathway. Taken together, our results highlight membrane-bound DKK-1 as a novel Treg-derived mediator to maintain immunological tolerance in T-cell-mediated autoimmune colitis. © 2017 The Authors. Immunology Published by John Wiley & Sons Ltd.

  6. CD4 T cell-mediated protection from lethal influenza: perforin and antibody-mediated mechanisms give a one-two punch.

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    Brown, Deborah M; Dilzer, Allison M; Meents, Dana L; Swain, Susan L

    2006-09-01

    The mechanisms whereby CD4 T cells contribute to the protective response against lethal influenza infection remain poorly characterized. To define the role of CD4 cells in protection against a highly pathogenic strain of influenza, virus-specific TCR transgenic CD4 effectors were generated in vitro and transferred into mice given lethal influenza infection. Primed CD4 effectors conferred protection against lethal infection over a broad range of viral dose. The protection mediated by CD4 effectors did not require IFN-gamma or host T cells, but did result in increased anti-influenza Ab titers compared with untreated controls. Further studies indicated that CD4-mediated protection at high doses of influenza required B cells, and that passive transfer of anti-influenza immune serum was therapeutic in B cell-deficient mice, but only when CD4 effectors were present. Primed CD4 cells also acquired perforin (Pfn)-mediated cytolytic activity during effector generation, suggesting a second mechanism used by CD4 cells to confer protection. Pfn-deficient CD4 effectors were less able to promote survival in intact BALB/c mice and were unable to provide protection in B cell-deficient mice, indicating that Ab-independent protection by CD4 effectors requires Pfn. Therefore, CD4 effectors mediate protection to lethal influenza through at least two mechanisms: Pfn-mediated cytotoxicity early in the response promoted survival independently of Ab production, whereas CD4-driven B cell responses resulted in high titer Abs that neutralized remaining virus.

  7. ZFAT plays critical roles in peripheral T cell homeostasis and its T cell receptor-mediated response

    International Nuclear Information System (INIS)

    Doi, Keiko; Fujimoto, Takahiro; Okamura, Tadashi; Ogawa, Masahiro; Tanaka, Yoko; Mototani, Yasumasa; Goto, Motohito; Ota, Takeharu; Matsuzaki, Hiroshi; Kuroki, Masahide; Tsunoda, Toshiyuki; Sasazuki, Takehiko; Shirasawa, Senji

    2012-01-01

    Highlights: ► We generated Cd4-Cre-mediated T cell-specific Zfat-deficient mice. ► Zfat-deficiency leads to reduction in the number of the peripheral T cells. ► Impaired T cell receptor-mediated response in Zfat-deficient peripheral T cells. ► Decreased expression of IL-7Rα, IL-2Rα and IL-2 in Zfat-deficient peripheral T cells. ► Zfat plays critical roles in peripheral T cell homeostasis. -- Abstract: ZFAT, originally identified as a candidate susceptibility gene for autoimmune thyroid disease, has been reported to be involved in apoptosis, development and primitive hematopoiesis. Zfat is highly expressed in T- and B-cells in the lymphoid tissues, however, its physiological function in the immune system remains totally unknown. Here, we generated the T cell-specific Zfat-deficient mice and demonstrated that Zfat-deficiency leads to a remarkable reduction in the number of the peripheral T cells. Intriguingly, a reduced expression of IL-7Rα and the impaired responsiveness to IL-7 for the survival were observed in the Zfat-deficient T cells. Furthermore, a severe defect in proliferation and increased apoptosis in the Zfat-deficient T cells following T cell receptor (TCR) stimulation was observed with a reduced IL-2Rα expression as well as a reduced IL-2 production. Thus, our findings reveal that Zfat is a critical regulator in peripheral T cell homeostasis and its TCR-mediated response.

  8. ZFAT plays critical roles in peripheral T cell homeostasis and its T cell receptor-mediated response

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Keiko [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan); Central Research Institute of Life Sciences for the Next Generation of Women Scientists, Fukuoka University, Fukuoka (Japan); Fujimoto, Takahiro [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan); Okamura, Tadashi [Division of Animal Models, Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo (Japan); Ogawa, Masahiro [Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan); Tanaka, Yoko [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Mototani, Yasumasa; Goto, Motohito [Division of Animal Models, Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo (Japan); Ota, Takeharu; Matsuzaki, Hiroshi [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Kuroki, Masahide [Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan); Tsunoda, Toshiyuki [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan); Sasazuki, Takehiko [Institute for Advanced Study, Kyushu University, Fukuoka (Japan); Shirasawa, Senji, E-mail: sshirasa@fukuoka-u.ac.jp [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan)

    2012-08-17

    Highlights: Black-Right-Pointing-Pointer We generated Cd4-Cre-mediated T cell-specific Zfat-deficient mice. Black-Right-Pointing-Pointer Zfat-deficiency leads to reduction in the number of the peripheral T cells. Black-Right-Pointing-Pointer Impaired T cell receptor-mediated response in Zfat-deficient peripheral T cells. Black-Right-Pointing-Pointer Decreased expression of IL-7R{alpha}, IL-2R{alpha} and IL-2 in Zfat-deficient peripheral T cells. Black-Right-Pointing-Pointer Zfat plays critical roles in peripheral T cell homeostasis. -- Abstract: ZFAT, originally identified as a candidate susceptibility gene for autoimmune thyroid disease, has been reported to be involved in apoptosis, development and primitive hematopoiesis. Zfat is highly expressed in T- and B-cells in the lymphoid tissues, however, its physiological function in the immune system remains totally unknown. Here, we generated the T cell-specific Zfat-deficient mice and demonstrated that Zfat-deficiency leads to a remarkable reduction in the number of the peripheral T cells. Intriguingly, a reduced expression of IL-7R{alpha} and the impaired responsiveness to IL-7 for the survival were observed in the Zfat-deficient T cells. Furthermore, a severe defect in proliferation and increased apoptosis in the Zfat-deficient T cells following T cell receptor (TCR) stimulation was observed with a reduced IL-2R{alpha} expression as well as a reduced IL-2 production. Thus, our findings reveal that Zfat is a critical regulator in peripheral T cell homeostasis and its TCR-mediated response.

  9. Circumvention of regulatory CD4(+) T cell activity during cross-priming strongly enhances T cell-mediated immunity.

    Science.gov (United States)

    Heit, Antje; Gebhardt, Friedemann; Lahl, Katharina; Neuenhahn, Michael; Schmitz, Frank; Anderl, Florian; Wagner, Hermann; Sparwasser, Tim; Busch, Dirk H; Kastenmüller, Kathrin

    2008-06-01

    Immunization with purified antigens is a safe and practical vaccination strategy but is generally unable to induce sustained CD8(+) T cell-mediated protection against intracellular pathogens. Most efforts to improve the CD8(+) T cell immunogenicity of these vaccines have focused on co-administration of adjuvant to support cross-presentation and dendritic cell maturation. In addition, it has been shown that CD4(+) T cell help during the priming phase contributes to the generation of protective CD8(+) memory T cells. In this report we demonstrate that the depletion of CD4(+) T cells paradoxically enhances long-lasting CD8-mediated protective immunity upon protein vaccination. Functional and genetic in vivo inactivation experiments attribute this enhancement primarily to MHC class II-restricted CD4(+) regulatory T cells (Treg), which appear to physiologically suppress the differentiation process towards long-living effector memory T cells. Since, in functional terms, this suppression by Treg largely exceeds the positive effects of conventional CD4(+) T cell help, even the absence of all CD4(+) T cells or lack of MHC class II-mediated interactions on priming dendritic cells result in enhanced CD8(+) T cell immunogenicity. These findings have important implications for the improvement of vaccines against intracellular pathogens or tumors, especially in patients with highly active Treg.

  10. Towards Future T Cell-Mediated Influenza Vaccines

    Directory of Open Access Journals (Sweden)

    Thi H. O. Nguyen

    2016-04-01

    Full Text Available Influenza A virus (IAVs infections impact significantly on global health, being particularly problematic in children, the elderly, pregnant women, indigenous populations and people with co-morbidities. Antibody-based vaccines require annual administration to combat rapidly acquired mutations modifying the surface haemagglutinin (HA and neuraminidase (NA glycoproteins. Conversely, influenza-specific CD8+ T cell responses directed at peptides derived from the more conserved internal virus proteins are known to be protective, suggesting that T cell-based vaccines may provide long-lasting cross-protection. This review outlines the importance of CD8+ T cell immunity to seasonal influenza and pandemic IAVs and summarises current vaccination strategies for inducing durable CD8+ T cell memory. Aspects of future IAV vaccine design and the use of live virus challenge in humans to establish proof of principle are also discussed.

  11. Systemic T Cells Immunosuppression of Glioma Stem Cell-Derived Exosomes Is Mediated by Monocytic Myeloid-Derived Suppressor Cells.

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    Rossana Domenis

    Full Text Available A major contributing factor to glioma development and progression is its ability to evade the immune system. Nano-meter sized vesicles, exosomes, secreted by glioma-stem cells (GSC can act as mediators of intercellular communication to promote tumor immune escape. Here, we investigated the immunomodulatory properties of GCS-derived exosomes on different peripheral immune cell populations. Healthy donor peripheral blood mononuclear cells (PBMCs stimulated with anti-CD3, anti-CD28 and IL-2, were treated with GSC-derived exosomes. Phenotypic characterization, cell proliferation, Th1/Th2 cytokine secretion and intracellular cytokine production were analysed by distinguishing among effector T cells, regulatory T cells and monocytes. In unfractionated PBMCs, GSC-derived exosomes inhibited T cell activation (CD25 and CD69 expression, proliferation and Th1 cytokine production, and did not affect cell viability or regulatory T-cell suppression ability. Furthermore, exosomes were able to enhance proliferation of purified CD4+ T cells. In PBMCs culture, glioma-derived exosomes directly promoted IL-10 and arginase-1 production and downregulation of HLA-DR by unstimulated CD14+ monocytic cells, that displayed an immunophenotype resembling that of monocytic myeloid-derived suppressor cells (Mo-MDSCs. Importantly, the removal of CD14+ monocytic cell fraction from PBMCs restored T-cell proliferation. The same results were observed with exosomes purified from plasma of glioblastoma patients. Our results indicate that glioma-derived exosomes suppress T-cell immune response by acting on monocyte maturation rather than on direct interaction with T cells. Selective targeting of Mo-MDSC to treat glioma should be considered with regard to how immune cells allow the acquirement of effector functions and therefore counteracting tumor progression.

  12. Dysregulated miR34a/diacylglycerol kinase ζ interaction enhances T-cell activation in acquired aplastic anemia.

    Science.gov (United States)

    Sun, Yuan-Xin; Li, Hui; Feng, Qi; Li, Xin; Yu, Ying-Yi; Zhou, Li-Wei; Gao, Yan; Li, Guo-Sheng; Ren, Juan; Ma, Chun-Hong; Gao, Cheng-Jiang; Peng, Jun

    2017-01-24

    Acquired aplastic anemia is an idiopathic paradigm of human bone marrow failure syndrome, which involves active destruction of hematopoietic stem cells and progenitors by cytotoxic T cells in the bone marrow. Aberrant expression of microRNAs in T cells has been shown to lead to development of certain autoimmune diseases. In the present study, we performed a microarray analysis of miRNA expression in bone marrow CD3+ T cells from patients with aplastic anemia and healthy controls. Overexpression of miR34a and underexpression of its target gene diacylglycerol kinase (DGK) ζ in bone marrow mononuclear cells were validated in 41 patients and associated with the severity of aplastic anemia. Further, the level of miR34a was higher in naïve T cells from patients than from controls. The role of miR34a and DGKζ in aplastic anemia was investigated in a murine model of immune-mediated bone marrow failure using miR34a-/- mice. After T-cell receptor stimulation in vitro, lymph node T cells from miR34a-/- mice demonstrated reduced activation and proliferation accompanied with a less profound down-regulation of DGKζ expression and decreased ERK phosphorylation compared to those from wild-type C57BL6 control mice. Infusion of 5 × 106 miR34a-/- lymph node T cells into sublethally irradiated CB6F1 recipients led to increased Lin-Sca1+CD117+ cells and less vigorous expansion of CD8+ T cells than injection of same number of wild-type lymph node cells. Our study demonstrates that the miR34a/DGKζ dysregulation enhances T-cell activation in aplastic anemia and targeting miR34a may represent a novel molecular therapeutic approach for patients with aplastic anemia.

  13. Double control systems for human T-cell leukemia virus type 1 by innate and acquired immunity.

    Science.gov (United States)

    Kannagi, Mari; Hasegawa, Atsuhiko; Kinpara, Shuichi; Shimizu, Yukiko; Takamori, Ayako; Utsunomiya, Atae

    2011-04-01

    Human T-cell leukemia virus type 1 (HTLV-1) is the causative retrovirus of adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-1-specific T-cell responses elicit antitumor and antiviral effects in experimental models, and are considered to be one of the most important determinants of the disease manifestation, since they are activated in HAM/TSP but not in ATL patients. The combination of low T-cell responses and elevated HTLV-1 proviral loads are features of ATL, and are also observed in a subpopulation of HTLV-1 carriers at the asymptomatic stage, suggesting that these features may be underlying risk factors. These risks may potentially be reduced by vaccination to activate HTLV-1-specific T-cell responses. HAM/TSP and ATL patients also differ in their levels of HTLV-1 mRNA expression, which are generally low in vivo but slightly higher in HAM/TSP patients. Our recent study indicated that viral expression in HTLV-1-infected T-cells is suppressed by stromal cells in culture through type-I IFNs. The suppression was reversible after isolation from the stromal cells, mimicking a long-standing puzzling phenomenon in HTLV-1 infection where the viral expression is very low in vivo and rapidly induced in vitro. Collectively, HTLV-1 is controlled by both acquired and innate immunity in vivo: HTLV-1-specific T-cells survey infected cells, and IFNs suppress viral expression. Both effects would contribute to a reduction in viral pathogenesis, although they may potentially influence or conflict with one another. The presence of double control systems for HTLV-1 infection provides a new concept for understanding the pathogenesis of HTLV-1-mediated malignant and inflammatory diseases. © 2011 Japanese Cancer Association.

  14. Human CAR T cells with cell-intrinsic PD-1 checkpoint blockade resist tumor-mediated inhibition

    Science.gov (United States)

    Cherkassky, Leonid; Morello, Aurore; Villena-Vargas, Jonathan; Feng, Yang; Dimitrov, Dimiter S.; Jones, David R.; Sadelain, Michel; Adusumilli, Prasad S.

    2016-01-01

    Following immune attack, solid tumors upregulate coinhibitory ligands that bind to inhibitory receptors on T cells. This adaptive resistance compromises the efficacy of chimeric antigen receptor (CAR) T cell therapies, which redirect T cells to solid tumors. Here, we investigated whether programmed death-1–mediated (PD-1–mediated) T cell exhaustion affects mesothelin-targeted CAR T cells and explored cell-intrinsic strategies to overcome inhibition of CAR T cells. Using an orthotopic mouse model of pleural mesothelioma, we determined that relatively high doses of both CD28- and 4-1BB–based second-generation CAR T cells achieved tumor eradication. CAR-mediated CD28 and 4-1BB costimulation resulted in similar levels of T cell persistence in animals treated with low T cell doses; however, PD-1 upregulation within the tumor microenvironment inhibited T cell function. At lower doses, 4-1BB CAR T cells retained their cytotoxic and cytokine secretion functions longer than CD28 CAR T cells. The prolonged function of 4-1BB CAR T cells correlated with improved survival. PD-1/PD-1 ligand [PD-L1] pathway interference, through PD-1 antibody checkpoint blockade, cell-intrinsic PD-1 shRNA blockade, or a PD-1 dominant negative receptor, restored the effector function of CD28 CAR T cells. These findings provide mechanistic insights into human CAR T cell exhaustion in solid tumors and suggest that PD-1/PD-L1 blockade may be an effective strategy for improving the potency of CAR T cell therapies. PMID:27454297

  15. Antigen-specific and nonspecific mediators of T cell/B cell cooperation. III. Characterization of the nonspecific mediator(s) from different sources.

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    Harwell, L; Kappler, J W; Marrack, P

    1976-05-01

    T cell-containing lymphoid populations produce a nonantigen-specific mediator(s) (NSM) which can replace T cell helper function in vitro in the response of B cells to sheep red blood cells (SRBC), but not to the hapten-protein conjugate, trinitrophenyl-keyhole limpet hemocyanin, (TNP-KLH). NSM produced under three conditions: 1) stimulation of KLH-primed cells with KLH; 2) allogeneic stimulation of normal spleen cells; and 3) stimulation of normal spleen cells with Con A (but not PHA) are indistinguishable on the basis of their biologic activity and m.w., estimated as 30 to 40,000 daltons by G-200 chromatography. Production of NSM is dependent on the presence of T cells. The action of NSM on B cells responding to SRBC in the presence of 2-mercaptoethanol is unaffected by severe macrophage depletion. Extensive absorption of NSM with SRBC failed to remove its activity, confirming its nonantigen-specific nature.

  16. Enhanced B-Raf-mediated NRF2 gene transcription and HATs-mediated NRF2 protein acetylation contributes to ABCC1-mediated chemoresistance and glutathione-mediated survival in acquired topoisomerase II poison-resistant cancer cells.

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    Chen, Huang-Hui; Chang, Hsin-Huei; Chang, Jang-Yang; Tang, Ya-Chu; Cheng, Yung-Chi; Lin, Li-Mei; Cheng, Shu-Ying; Huang, Chih-Hsiang; Sun, Man-Wu; Chen, Chiung-Tong; Kuo, Ching-Chuan

    2017-12-01

    Nuclear factor erythroid-2-related factor 2 (NRF2) mainly regulates transcriptional activation through antioxidant-responsive elements (AREs) present in the promoters of NRF2 target genes. Recently, we found that NRF2 was overexpressed in a KB-derived drug-resistant cancer cell panel. In this panel, KB-7D cells, which show acquired resistance to topoisomerase II (Top II) poisons, exhibited the highest NRF2 activation. To investigate whether NRF2 directly contributed to acquired resistance against Top II poisons, we manipulated NRF2 by genetic and pharmacological approaches. The result demonstrated that silencing of NRF2 by RNA interference increased the sensitivity and treatment with NRF2 activator decreased the sensitivity of KB and KB-7D cells toward Top II poisons. Further, increased B-Raf-mediated NRF2 gene transcription and HATs-mediated NRF2 protein acetylation activated NRF2 signaling in KB-7D cells. Moreover, increased binding of NRF2 to an ARE in the promoter of ATP-binding cassette subfamily C member 1 (ABCC1) directly contributed to Top II poison resistance. In addition, activation of NRF2 increased glutathione level and antioxidant capacity in KB-7D cells compared with that in KB cells; moreover, high glutathione level provided survival advantage to KB-7D cells. Our study is the first to show that aberrant NRF2 activation is via increased B-Raf-mediated NRF2 gene transcription and HATs-mediated NRF2 protein acetylation, which increases the acquired resistance and promote the survival of Top II poison-resistant cancer cells. Importantly, NRF2 downstream effectors ABCC1 and glutathione directly contribute to acquired resistance and survival, respectively. These results suggest that blockade of NRF2 signaling may enhance therapeutic efficacy and reduce the survival of Top II poison-refractory tumors in clinical. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Cre-mediated cell ablation contests mast cell contribution in models of antibody- and T cell-mediated autoimmunity.

    Science.gov (United States)

    Feyerabend, Thorsten B; Weiser, Anne; Tietz, Annette; Stassen, Michael; Harris, Nicola; Kopf, Manfred; Radermacher, Peter; Möller, Peter; Benoist, Christophe; Mathis, Diane; Fehling, Hans Jörg; Rodewald, Hans-Reimer

    2011-11-23

    Immunological functions of mast cells remain poorly understood. Studies in Kit mutant mice suggest key roles for mast cells in certain antibody- and T cell-mediated autoimmune diseases. However, Kit mutations affect multiple cell types of both immune and nonimmune origin. Here, we show that targeted insertion of Cre-recombinase into the mast cell carboxypeptidase A3 locus deleted mast cells in connective and mucosal tissues by a genotoxic Trp53-dependent mechanism. Cre-mediated mast cell eradication (Cre-Master) mice had, with the exception of a lack of mast cells and reduced basophils, a normal immune system. Cre-Master mice were refractory to IgE-mediated anaphylaxis, and this defect was rescued by mast cell reconstitution. This mast cell-deficient strain was fully susceptible to antibody-induced autoimmune arthritis and to experimental autoimmune encephalomyelitis. Differences comparing Kit mutant mast cell deficiency models to selectively mast cell-deficient mice call for a systematic re-evaluation of immunological functions of mast cells beyond allergy. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. DNA fragmentation: manifestation of target cell destruction mediated by cytotoxic T-cell lines, lymphotoxin-secreting helper T-cell clones, and cell-free lymphotoxin-containing supernatant

    International Nuclear Information System (INIS)

    Schmid, D.S.; Tite, J.P.; Ruddle, N.H.

    1986-01-01

    A Lyt-2 + , trinitrophenyl-specific, lymphotoxin-secreting, cytotoxic T-cell line, PCl 55, mediates the digestion of target cell DNA into discretely sized fragments. This phenomenon manifests itself within 30 min after effector cell encounter as measured by the release of 3 H counts from target cells prelabeled with [ 3 H]deoxythymidine and occurs even at very low effector to target cell ratios (0.25:1). A Lyt-1 + , ovalbumin-specific, lymphotoxin-secreting T-helper cell clone, 5.9.24, is also able to mediate fragmentation of target cell DNA over a time course essentially indistinguishable from the cytotoxic T lymphocyte-mediated hit. Cell-free lymphotoxin-containing supernatants also cause release of DNA from targets, although they require a longer time course, on the order of 24 hr. In contrast, lysis of cells by antibody plus complement or Triton X-100 does not result in DNA release even after extended periods of incubation (24 hr). All three treatments that result in the release of DNA from cells cause fragmentation of that DNA into discretely sized pieces that are multiples of 200 base pairs. The results thus suggest that cytotoxic T cells, lymphotoxin-secreting helper clones with cytolytic activity, and lymphotoxin all effect target cell destruction by means of a similar mechanism and that observed differences in time course and the absence of target cell specificity in killing mediated by lymphotoxin may simply reflect differences in the mode of toxin delivery

  19. Phosphoproteomics Reveals Regulatory T Cell-Mediated DEF6 Dephosphorylation That Affects Cytokine Expression in Human Conventional T Cells

    KAUST Repository

    Joshi, Rubin N.

    2017-09-25

    Regulatory T cells (Tregs) control key events of immune tolerance, primarily by suppression of effector T cells. We previously revealed that Tregs rapidly suppress T cell receptor (TCR)-induced calcium store depletion in conventional CD4CD25 T cells (Tcons) independently of IP levels, consequently inhibiting NFAT signaling and effector cytokine expression. Here, we study Treg suppression mechanisms through unbiased phosphoproteomics of primary human Tcons upon TCR stimulation and Treg-mediated suppression, respectively. Tregs induced a state of overall decreased phosphorylation as opposed to TCR stimulation. We discovered novel phosphosites (T595_S597) in the DEF6 (SLAT) protein that were phosphorylated upon TCR stimulation and conversely dephosphorylated upon coculture with Tregs. Mutation of these DEF6 phosphosites abrogated interaction of DEF6 with the IP receptor and affected NFAT activation and cytokine transcription in primary Tcons. This novel mechanism and phosphoproteomics data resource may aid in modifying sensitivity of Tcons to Treg-mediated suppression in autoimmune disease or cancer.

  20. Ezh2 regulates transcriptional and post-translational expression of T-bet and promotes Th1 cell responses mediating aplastic anemia in mice1

    Science.gov (United States)

    Tong, Qing; He, Shan; Xie, Fang; Mochizuki, Kazuhiro; Liu, Yongnian; Mochizuki, Izumi; Meng, Lijun; Sun, Hongxing; Zhang, Yanyun; Guo, Yajun; Hexner, Elizabeth; Zhang, Yi

    2014-01-01

    Acquired aplastic anemia (AA) is a potentially fatal bone marrow (BM) failure syndrome. IFN-γ-producing T helper (Th)1 CD4+ T cells mediate the immune destruction of hematopoietic cells, and are central to the pathogenesis. However, the molecular events that control the development of BM-destructive Th1 cells remain largely unknown. Ezh2 is a chromatin-modifying enzyme that regulates multiple cellular processes primarily by silencing gene expression. We recently reported that Ezh2 is crucial for inflammatory T cell responses after allogeneic BM transplantation. To elucidate whether Ezh2 mediates pathogenic Th1 responses in AA and the mechanism of Ezh2 action in regulating Th1 cells, we studied the effects of Ezh2 inhibition in CD4+ T cells using a mouse model of human AA. Conditionally deleting Ezh2 in mature T cells dramatically reduced the production of BM-destructive Th1 cells in vivo, decreased BM-infiltrating Th1 cells, and rescued mice from BM failure. Ezh2 inhibition resulted in significant decrease in the expression of Tbx21 and Stat4 (which encode transcription factors T-bet and STAT4, respectively). Introduction of T-bet but not STAT4 into Ezh2-deficient T cells fully rescued their differentiation into Th1 cells mediating AA. Ezh2 bound to the Tbx21 promoter in Th1 cells, and directly activated Tbx21 transcription. Unexpectedly, Ezh2 was also required to prevent proteasome-mediated degradation of T-bet protein in Th1 cells. Our results identify T-bet as the transcriptional and post-translational Ezh2 target that acts together to generate BM-destructive Th1 cells, and highlight the therapeutic potential of Ezh2 inhibition in reducing AA and other autoimmune diseases. PMID:24760151

  1. T Cell-Mediated Modulation of Mast Cell Function: Heterotypic Adhesion-Induced Stimulatory or Inhibitory Effects

    Directory of Open Access Journals (Sweden)

    Yoseph A. Mekori

    2012-01-01

    Full Text Available Close physical proximity between mast cells and T cells has been demonstrated in several T cell mediated inflammatory processes such as rheumatoid arthritis and sarcoidosis. However, the way by which mast cells are activated in these T cell-mediated immune responses has not been fully elucidated. We have identified and characterized a novel mast cell activation pathway initiated by physical contact with activated T cells, and showed that this pathway is associated with degranulation and cytokine release. The signaling events associated with this pathway of mast cell activation have also been elucidated confirming the activation of the Ras MAPK systems. More recently, we hypothesized and demonstrated that mast cells may also be activated by microparticles released from activated T cells that are considered as miniature version of a cell. By extension, microparticles might affect the activity of mast cells, which are usually not in direct contact with T cells at the inflammatory site. Recent works have also focused on the effects of regulatory T cells on mast cells. These reports highlighted the importance of the cytokines IL-2 and IL-9, produced by mast cells and T cells, respectively, in obtaining optimal immune suppression. Finally, physical contact, associated by OX40-OX40L engagement has been found to underlie the down-regulatory effects exerted by regulatory T cells on mast cell function.

  2. Increased T-helper 17 cell differentiation mediated by exosome-mediated microRNA-451 redistribution in gastric cancer infiltrated T cells.

    Science.gov (United States)

    Liu, Feng; Bu, Zhouyan; Zhao, Feng; Xiao, Daping

    2018-01-01

    MicroRNA (miR)-451 is a cell metabolism-related miRNA that can mediate cell energy-consuming models by several targets. As miR-451 can promote mechanistic target of rapamycin (mTOR) activity, and increased mTOR activity is related to increased differentiation of T-helper 17 (Th17) cells, we sought to investigate whether miR-451 can redistribute from cancer cells to infiltrated T cells and enhance the distribution of Th17 cells through mTOR. Real-time PCR was used for detecting expression of miR-451 in gastric cancer, tumor infiltrated T cells and exosomes, and distribution of Th17 was evaluated by both flow cytometry and immunohistochemistry (IHC). Immunofluorescence staining was used in monitoring the exosome-enveloped miR-451 from cancer cells to T cells with different treatments, and signaling pathway change was analyzed by western blot. miR-451 decreased significantly in gastric cancer (GC) tissues but increased in infiltrated T cells and exosomes; tumor miR-451 was negatively related to infiltrated T cells and exosome miR-451. Exosome miR-451 can not only serve as an indicator for poor prognosis of post-operation GC patients but is also related to increased Th17 distribution in gastric cancer. miR-451 can redistribute from cancer cells to T cells with low glucose treatment. Decreased 5' AMP-activated protein kinase (AMPK) and increased mTOR activity was investigated in miR-451 redistributed T cells and the Th17 polarized differentiation of these T cells were also increased. Exosome miR-451 derived from tumor tissues can serve as an indicator for poor prognosis and redistribution of miR-451 from cancer cells to infiltrated T cells in low glucose treatment can enhance Th17 differentiation by enhancing mTOR activity. © 2017 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

  3. Challenges and opportunities for T cell-mediated strategies to eliminate HIV reservoirs

    Directory of Open Access Journals (Sweden)

    Mark Alan Brockman

    2015-10-01

    Full Text Available HIV’s ability to establish latent reservoirs of reactivation-competent virus is the major barrier to cure. Shock and kill methods consisting of latency reversing agents (LRAs followed by elimination of reactivating cells through cytopathic effects are under active development. However, the clinical efficacy of LRAs remains to be established. Moreover, recent studies indicate that reservoirs may not be reduced efficiently by either viral cytopathic or CD8+ T-cell-mediated mechanisms. In this perspective, we highlight challenges to T-cell-mediated elimination of HIV reservoirs, including characteristics of responding T-cells, aspects of the cellular reservoirs and properties of the latent virus itself. We also discuss potential strategies to overcome these challenges by targeting the antiviral activity of T-cells towards appropriate viral antigens following latency.

  4. Single-cell analysis reveals a link between CD3- and CD59-mediated signaling pathways in Jurkat T cells

    International Nuclear Information System (INIS)

    Lipp, A. M.

    2012-01-01

    Elevation of intracellular free calcium concentration ([Ca2+]i) is a key signal during T cell activation and is commonly used as a read-out parameter for stimulation of T cell signaling. Upon T cell stimulation a variety of calcium signals is produced by individual cells of the T cell population and the type of calcium signal strongly influences cell fate decisions. The heterogeneous nature of T cells is masked in ensemble measurements, which highlights the need for single-cell measurements. In this study we used single-cell calcium measurements in Jurkat cells to investigate signaling pathways, which are triggered by different proteins, namely CD3 and CD59. By application of an automated cluster algorithm the presented assay provides unbiased analysis of a large data set of individual calcium time traces generated by the whole cell population. By using this method we could demonstrate that the Jurkat population generates heterogeneous calcium signals in a stimulus-dependent manner. Furthermore, our data revealed the existence of a link between CD3- and CD59-mediated signaling pathways. Single-cell calcium measurements in Jurkat cells expressing different levels of the T cell receptor (TCR) complex indicated that CD59-mediated calcium signaling is critically dependent on TCR surface expression levels. In addition, triggering CD59-mediated calcium signaling resulted in down-regulation of TCR surface expression levels, which is known to happen upon direct TCR triggering too. Moreover, by using siRNA-mediated protein knock-downs and protein knock-out Jurkat mutants we could show that CD3- and CD59-mediated calcium signaling require identical key proteins. We therefore explored by which mechanism CD59-mediated signaling couples into TCR-mediated signaling. Fluorescence recovery after photobleaching (FRAP) experiments and live-cell protein-protein interaction assays provided no evidence of a direct physical interaction between CD3- and CD59-mediated signaling pathways

  5. Human memory CD8 T cell effector potential is epigenetically preserved during in vivo homeostasis.

    Science.gov (United States)

    Abdelsamed, Hossam A; Moustaki, Ardiana; Fan, Yiping; Dogra, Pranay; Ghoneim, Hazem E; Zebley, Caitlin C; Triplett, Brandon M; Sekaly, Rafick-Pierre; Youngblood, Ben

    2017-06-05

    Antigen-independent homeostasis of memory CD8 T cells is vital for sustaining long-lived T cell-mediated immunity. In this study, we report that maintenance of human memory CD8 T cell effector potential during in vitro and in vivo homeostatic proliferation is coupled to preservation of acquired DNA methylation programs. Whole-genome bisulfite sequencing of primary human naive, short-lived effector memory (T EM ), and longer-lived central memory (T CM ) and stem cell memory (T SCM ) CD8 T cells identified effector molecules with demethylated promoters and poised for expression. Effector-loci demethylation was heritably preserved during IL-7- and IL-15-mediated in vitro cell proliferation. Conversely, cytokine-driven proliferation of T CM and T SCM memory cells resulted in phenotypic conversion into T EM cells and was coupled to increased methylation of the CCR7 and Tcf7 loci. Furthermore, haploidentical donor memory CD8 T cells undergoing in vivo proliferation in lymphodepleted recipients also maintained their effector-associated demethylated status but acquired T EM -associated programs. These data demonstrate that effector-associated epigenetic programs are preserved during cytokine-driven subset interconversion of human memory CD8 T cells. © 2017 Abdelsamed et al.

  6. Role of macrophage inflammatory protein-1alpha in T-cell-mediated immunity to viral infection

    DEFF Research Database (Denmark)

    Madsen, Andreas N; Nansen, Anneline; Christensen, Jan P

    2003-01-01

    The immune response to lymphocytic choriomeningitis virus in mice lacking macrophage inflammatory protein-1alpha (MIP-1alpha) was evaluated. Generation of virus-specific effector T cells is unimpaired in MIP-1alpha-deficient mice. Furthermore, MIP-1alpha is not required for T-cell-mediated virus...... control or virus-induced T-cell-dependent inflammation. Thus, MIP-1alpha is not mandatory for T-cell-mediated antiviral immunity....

  7. Acquired EGFR L718V mutation mediates resistance to osimertinib in non-small cell lung cancer but retains sensitivity to afatinib.

    Science.gov (United States)

    Liu, Yutao; Li, Yan; Ou, Qiuxiang; Wu, Xue; Wang, Xiaonan; Shao, Yang W; Ying, Jianming

    2018-04-01

    Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are promising targeted therapies for EGFR-mutated non-small-cell lung cancer (NSCLC) patients. However, acquired resistance inevitably develops. Comprehensive and dynamic companion genomic diagnosis can gain insights into underlying resistance mechanisms, thereby help oncologists and patients to make informed decision on the potential benefit of the treatment. A 67-year-old male who was initially diagnosed of EGFR L858R-mediated NSCLC received multiple lines of chemotherapy and EGFR TKI therapies after surgery. The EGFR mutational status of individual metastatic lesion was determined by genetic testing of the tumor tissue biopsies using next generation sequencing (NGS) throughout the patient's clinical course. An acquired potentially drug-resistant EGFR mutation was functionally validated in vitro and its sensitivity to different EGFR TKIs was assessed simultaneously. We have identified distinct resistance mechanisms to EGFR blockade in different metastatic lung lesions. Acquired EGFR T790M was first detected that leads to the resistance to the gefitinib treatment. Consequently, osimertinib was administrated and the response lasted until disease progressed. We identified a newly acquired EGFR L718V mutation in one lesion in conjunction with L858R, but not T790M, which showed stable disease on the following erlotinib treatment, while EGFR C797S together with L858R/T790M was detected in the other lesion that continuously progressed. In vitro functional studies demonstrated that EGFR-L858R/L718V confers resistance to osimertinib, but retains sensitivity to the second generation TKI afatinib. We reported that distinct resistance mechanisms could arise in different metastases within the same patient in response to EGFR blockade. We also demonstrated in vitro that EGFR L718V mutation mediates resistance to osimertinib, but retains sensitivity to afatinib. We evidenced that dynamic companion genomic

  8. HBV-specific CD4+ cytotoxic T cells in hepatocellular carcinoma are less cytolytic toward tumor cells and suppress CD8+ T cell-mediated antitumor immunity.

    Science.gov (United States)

    Meng, Fanzhi; Zhen, Shoumei; Song, Bin

    2017-08-01

    In East Asia and sub-Saharan Africa, chronic infection is the main cause of the development of hepatocellular carcinoma, an aggressive cancer with low survival rate. Cytotoxic T cell-based immunotherapy is a promising treatment strategy. Here, we investigated the possibility of using HBV-specific CD4 + cytotoxic T cells to eliminate tumor cells. The naturally occurring HBV-specific cytotoxic CD4 + and CD8 + T cells were identified by HBV peptide pool stimulation. We found that in HBV-induced hepatocellular carcinoma patients, the HBV-specific cytotoxic CD4 + T cells and cytotoxic CD8 + T cells were present at similar numbers. But compared to the CD8 + cytotoxic T cells, the CD4 + cytotoxic T cells secreted less cytolytic factors granzyme A (GzmA) and granzyme B (GzmB), and were less effective at eliminating tumor cells. In addition, despite being able to secrete cytolytic factors, CD4 + T cells suppressed the cytotoxicity mediated by CD8 + T cells, even when CD4 + CD25 + regulator T cells were absent. Interestingly, we found that interleukin 10 (IL-10)-secreting Tr1 cells were enriched in the cytotoxic CD4 + T cells. Neutralization of IL-10 abrogated the suppression of CD8 + T cells by CD4 + CD25 - T cells. Neither the frequency nor the absolute number of HBV-specific CD4 + cytotoxic T cells were correlated with the clinical outcome of advanced stage hepatocellular carcinoma patients. Together, this study demonstrated that in HBV-related hepatocellular carcinoma, CD4 + T cell-mediated cytotoxicity was present naturally in the host and had the potential to exert antitumor immunity, but its capacity was limited and was associated with immunoregulatory properties. © 2017 APMIS. Published by John Wiley & Sons Ltd.

  9. Characterization of CD4+ T cell-mediated cytotoxicity in patients with multiple myeloma.

    Science.gov (United States)

    Zhang, Xiaole; Gao, Lei; Meng, Kai; Han, Chunting; Li, Qiang; Feng, Zhenjun; Chen, Lei

    2018-05-01

    Multiple myeloma (MM) is an incurable cancer characterized by the development of malignant plasma cells. The CD8 T cell-mediated cytotoxicity is considered a major player in antitumor immunity, but in MM patients, the CD8 T cells displayed senescence markers and were functionally impaired. To investigate whether cytotoxic CD4 T cells could act as a treatment alternative in MM, we examined the frequency and function of naturally occurring cytotoxic CD4 T cells in MM patients. The cytotoxic CD4 T cells were identified as granzyme-A, granzyme B-, and perforin-expressing CD4 T cells, and their frequencies were significantly upregulated in MM patients when compared with healthy controls. The frequencies of cytotoxic CD4 T cells in MM patients were not associated with the frequencies of cytotoxic CD8 T cells, but were negatively associated with disease severity. Interestingly, the expression levels of inhibitory molecules, including PD-1 and CTLA-4, were significantly lower in cytotoxic CD4 T cells than in cytotoxic CD8 T cells. When co-incubated with autologous CD38 + CD138 + plasma cells, CD4 T cells were capable of eliminating plasma cells with varying degrees of efficacy. In MM patients, the frequency of circulating plasma cells was negatively correlated with the frequency of cytotoxic CD4 T cells. Therefore, CD4 T cell-mediated cytotoxicity existed naturally in MM patients and could potentially act as an option in antitumor therapies. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. CEA/CD3-bispecific T cell-engaging (BiTE) antibody-mediated T lymphocyte cytotoxicity maximized by inhibition of both PD1 and PD-L1.

    Science.gov (United States)

    Osada, Takuya; Patel, Sandip P; Hammond, Scott A; Osada, Koya; Morse, Michael A; Lyerly, H Kim

    2015-06-01

    Bispecific T cell-engaging (BiTE) antibodies recruit polyclonal cytotoxic T cells (CTL) to tumors. One such antibody is carcinoembryonic antigen (CEA) BiTE that mediates T cell/tumor interaction by simultaneously binding CD3 expressed by T cells and CEA expressed by tumor cells. A widely operative mechanism for mitigating cytotoxic T cell-mediated killing is the interaction of tumor-expressed PD-L1 with T cell-expressed PD-1, which may be partly reversed by PD-1/PD-L1 blockade. We hypothesized that PD-1/PD-L1 blockade during BiTE-mediated T cell killing would enhance CTL function. Here, we determined the effects of PD-1 and PD-L1 blockade during initial T cell-mediated killing of CEA-expressing human tumor cell lines in vitro, as well as subsequent T cell-mediated killing by T lymphocytes that had participated in tumor cell killing. We observed a rapid upregulation of PD-1 expression and diminished cytolytic function of T cells after they had engaged in CEA BiTE-mediated killing of tumors. T cell cytolytic activity in vitro could be maximized by administration of anti-PD-1 or anti-PD-L1 antibodies alone or in combination if applied prior to a round of T cell killing, but T cell inhibition could not be fully reversed by this blockade once the T cells had killed tumor. In conclusion, our findings demonstrate that dual blockade of PD-1 and PD-L1 maximizes T cell killing of tumor directed by CEA BiTE in vitro, is more effective if applied early, and provides a rationale for clinical use.

  11. NOD1 cooperates with TLR2 to enhance T cell receptor-mediated activation in CD8 T cells.

    Directory of Open Access Journals (Sweden)

    Blandine C Mercier

    Full Text Available Pattern recognition receptors (PRR, like Toll-like receptors (TLR and NOD-like receptors (NLR, are involved in the detection of microbial infections and tissue damage by cells of the innate immune system. Recently, we and others have demonstrated that TLR2 can additionally function as a costimulatory receptor on CD8 T cells. Here, we establish that the intracytosolic receptor NOD1 is expressed and functional in CD8 T cells. We show that C12-iEDAP, a synthetic ligand for NOD1, has a direct impact on both murine and human CD8 T cells, increasing proliferation and effector functions of cells activated via their T cell receptor (TCR. This effect is dependent on the adaptor molecule RIP2 and is associated with an increased activation of the NF-κB, JNK and p38 signaling pathways. Furthermore, we demonstrate that NOD1 stimulation can cooperate with TLR2 engagement on CD8 T cells to enhance TCR-mediated activation. Altogether our results indicate that NOD1 might function as an alternative costimulatory receptor in CD8 T cells. Our study provides new insights into the function of NLR in T cells and extends to NOD1 the recent concept that PRR stimulation can directly control T cell functions.

  12. Comparison of lentiviral and sleeping beauty mediated αβ T cell receptor gene transfer.

    Directory of Open Access Journals (Sweden)

    Anne-Christine Field

    Full Text Available Transfer of tumour antigen-specific receptors to T cells requires efficient delivery and integration of transgenes, and currently most clinical studies are using gamma retroviral or lentiviral systems. Whilst important proof-of-principle data has been generated for both chimeric antigen receptors and αβ T cell receptors, the current platforms are costly, time-consuming and relatively inflexible. Alternative, more cost-effective, Sleeping Beauty transposon-based plasmid systems could offer a pathway to accelerated clinical testing of a more diverse repertoire of recombinant high affinity T cell receptors. Nucleofection of hyperactive SB100X transposase-mediated stable transposition of an optimised murine-human chimeric T cell receptor specific for Wilm's tumour antigen from a Sleeping Beauty transposon plasmid. Whilst transfer efficiency was lower than that mediated by lentiviral transduction, cells could be readily enriched and expanded, and mediated effective target cells lysis in vitro and in vivo. Integration sites of transposed TCR genes in primary T cells were almost randomly distributed, contrasting the predilection of lentiviral vectors for transcriptionally active sites. The results support exploitation of the Sleeping Beauty plasmid based system as a flexible and adaptable platform for accelerated, early-phase assessment of T cell receptor gene therapies.

  13. CRISPR-Cas9 mediated LAG-3 disruption in CAR-T cells.

    Science.gov (United States)

    Zhang, Yongping; Zhang, Xingying; Cheng, Chen; Mu, Wei; Liu, Xiaojuan; Li, Na; Wei, Xiaofei; Liu, Xiang; Xia, Changqing; Wang, Haoyi

    2017-12-01

    T cells engineered with chimeric antigen receptor (CAR) have been successfully applied to treat advanced refractory B cell malignancy. However, many challenges remain in extending its application toward the treatment of solid tumors. The immunosuppressive nature of tumor microenvironment is considered one of the key factors limiting CAR-T efficacy. One negative regulator of Tcell activity is lymphocyte activation gene-3 (LAG-3). We successfully generated LAG-3 knockout Tand CAR-T cells with high efficiency using CRISPR-Cas9 mediated gene editing and found that the viability and immune phenotype were not dramatically changed during in vitro culture. LAG-3 knockout CAR-T cells displayed robust antigen-specific antitumor activity in cell culture and in murine xenograft model, which is comparable to standard CAR-T cells. Our study demonstrates an efficient approach to silence immune checkpoint in CAR-T cells via gene editing.

  14. Acquired transcriptional programming in functional and exhausted virus-specific CD8 T cells.

    Science.gov (United States)

    Youngblood, Ben; Wherry, E John; Ahmed, Rafi

    2012-01-01

    Failure to control viral infections such as HIV results in T-cell receptor (TCR) and inhibitory receptor driven exhaustion of antigen-specific T cells. Persistent signaling by these receptors during chronic viral infection sculpts the transcriptional regulatory programs of virus-specific T cells. The resulting gene expression profile is tailored to temper the potentially damaging effector functions of cytotoxic T cells and adapt them to an antigen-rich and inflammation-rich environment. Here we review recent studies investigating mechanisms of transcriptional regulation of effector, functional memory, and exhausted T-cell functions during acute versus chronic infections. Patterns of gene expression in virus-specific CD8 T cells are a result of a combination of pro and inhibitory signals from antigen presentation (TCR-mediated) and co-inhibitory receptor ligation (PD-1, 2B4). Further, memory-specific transcriptional regulation of 2B4 expression and signaling impose a self-limiting secondary effector response to a prolonged viral infection. Additionally, differentiation of functional memory CD8 T cells is coupled with acquisition of a repressive epigenetic program for PD-1 expression. However, chronic infection provides a signal that blocks the acquisition of these epigenetic modifications reinforcing the suppression of cytotoxic lymphocyte (CTL) functions in exhausted cells. Current findings suggest that the mechanism(s) that delineate functional memory versus exhaustion are coupled with acquisition of transcriptional programs at the effector stage of differentiation, reinforced by cessation or persistence of TCR signaling.

  15. Identification of a regulatory T cell specific cell surface molecule that mediates suppressive signals and induces Foxp3 expression.

    Science.gov (United States)

    Wang, Rui; Wan, Qi; Kozhaya, Lina; Fujii, Hodaka; Unutmaz, Derya

    2008-07-16

    Regulatory T (T(reg)) cells control immune activation and maintain tolerance. How T(regs) mediate their suppressive function is unclear. Here we identified a cell surface molecule, called GARP, (or LRRC32), which within T cells is specifically expressed in T(regs) activated through the T cell receptor (TCR). Ectopic expression of GARP in human naïve T (T(N)) cells inhibited their proliferation and cytokine secretion upon TCR activation. Remarkably, GARP over-expression in T(N) cells induced expression of T(reg) master transcription factor Foxp3 and endowed them with a partial suppressive function. The extracellular but not the cytoplasmic region of GARP, was necessary for these functions. Silencing Foxp3 in human T(reg) cells reduced expression of GARP and attenuated their suppressive function. However, GARP function was not affected when Foxp3 was downregulated in GARP-overexpressing cells, while silencing GARP in Foxp3-overexpressing cells reduced their suppressive activity. These findings reveal a novel cell surface molecule-mediated regulatory mechanism, with implications for modulating aberrant immune responses.

  16. Identification of a regulatory T cell specific cell surface molecule that mediates suppressive signals and induces Foxp3 expression.

    Directory of Open Access Journals (Sweden)

    Rui Wang

    2008-07-01

    Full Text Available Regulatory T (T(reg cells control immune activation and maintain tolerance. How T(regs mediate their suppressive function is unclear. Here we identified a cell surface molecule, called GARP, (or LRRC32, which within T cells is specifically expressed in T(regs activated through the T cell receptor (TCR. Ectopic expression of GARP in human naïve T (T(N cells inhibited their proliferation and cytokine secretion upon TCR activation. Remarkably, GARP over-expression in T(N cells induced expression of T(reg master transcription factor Foxp3 and endowed them with a partial suppressive function. The extracellular but not the cytoplasmic region of GARP, was necessary for these functions. Silencing Foxp3 in human T(reg cells reduced expression of GARP and attenuated their suppressive function. However, GARP function was not affected when Foxp3 was downregulated in GARP-overexpressing cells, while silencing GARP in Foxp3-overexpressing cells reduced their suppressive activity. These findings reveal a novel cell surface molecule-mediated regulatory mechanism, with implications for modulating aberrant immune responses.

  17. Deep sequencing and flow cytometric characterization of expanded effector memory CD8+CD57+ T cells frequently reveals T-cell receptor Vβ oligoclonality and CDR3 homology in acquired aplastic anemia.

    Science.gov (United States)

    Giudice, Valentina; Feng, Xingmin; Lin, Zenghua; Hu, Wei; Zhang, Fanmao; Qiao, Wangmin; Ibanez, Maria Del Pilar Fernandez; Rios, Olga; Young, Neal S

    2018-05-01

    Oligoclonal expansion of CD8 + CD28 - lymphocytes has been considered indirect evidence for a pathogenic immune response in acquired aplastic anemia. A subset of CD8 + CD28 - cells with CD57 expression, termed effector memory cells, is expanded in several immune-mediated diseases and may have a role in immune surveillance. We hypothesized that effector memory CD8 + CD28 - CD57 + cells may drive aberrant oligoclonal expansion in aplastic anemia. We found CD8 + CD57 + cells frequently expanded in the blood of aplastic anemia patients, with oligoclonal characteristics by flow cytometric Vβ usage analysis: skewing in 1-5 Vβ families and frequencies of immunodominant clones ranging from 1.98% to 66.5%. Oligoclonal characteristics were also observed in total CD8 + cells from aplastic anemia patients with CD8 + CD57 + cell expansion by T-cell receptor deep sequencing, as well as the presence of 1-3 immunodominant clones. Oligoclonality was confirmed by T-cell receptor repertoire deep sequencing of enriched CD8 + CD57 + cells, which also showed decreased diversity compared to total CD4 + and CD8 + cell pools. From analysis of complementarity-determining region 3 sequences in the CD8 + cell pool, a total of 29 sequences were shared between patients and controls, but these sequences were highly expressed in aplastic anemia subjects and also present in their immunodominant clones. In summary, expansion of effector memory CD8 + T cells is frequent in aplastic anemia and mirrors Vβ oligoclonal expansion. Flow cytometric Vβ usage analysis combined with deep sequencing technologies allows high resolution characterization of the T-cell receptor repertoire, and might represent a useful tool in the diagnosis and periodic evaluation of aplastic anemia patients. (Registered at clinicaltrials.gov identifiers: 00001620, 01623167, 00001397, 00071045, 00081523, 00961064 ). Copyright © 2018 Ferrata Storti Foundation.

  18. Surface receptor Toso controls B cell-mediated regulation of T cell immunity.

    Science.gov (United States)

    Yu, Jinbo; Duong, Vu Huy Hoang; Westphal, Katrin; Westphal, Andreas; Suwandi, Abdulhadi; Grassl, Guntram A; Brand, Korbinian; Chan, Andrew C; Föger, Niko; Lee, Kyeong-Hee

    2018-05-01

    The immune system is tightly controlled by regulatory processes that allow for the elimination of invading pathogens, while limiting immunopathological damage to the host. In the present study, we found that conditional deletion of the cell surface receptor Toso on B cells unexpectedly resulted in impaired proinflammatory T cell responses, which led to impaired immune protection in an acute viral infection model and was associated with reduced immunopathological tissue damage in a chronic inflammatory context. Toso exhibited its B cell-inherent immunoregulatory function by negatively controlling the pool of IL-10-competent B1 and B2 B cells, which were characterized by a high degree of self-reactivity and were shown to mediate immunosuppressive activity on inflammatory T cell responses in vivo. Our results indicate that Toso is involved in the differentiation/maintenance of regulatory B cells by fine-tuning B cell receptor activation thresholds. Furthermore, we showed that during influenza A-induced pulmonary inflammation, the application of Toso-specific antibodies selectively induced IL-10-competent B cells at the site of inflammation and resulted in decreased proinflammatory cytokine production by lung T cells. These findings suggest that Toso may serve as a novel therapeutic target to dampen pathogenic T cell responses via the modulation of IL-10-competent regulatory B cells.

  19. The role of B cell-mediated T cell costimulation in the efficacy of the T cell retargeting bispecific antibody BIS20x3

    NARCIS (Netherlands)

    Stel, AJ; Kroesen, BJ; Jacobs, Susan; Groen, H; de Leij, LFMH; Kluin-Nelemans, HC; Withoff, S

    2004-01-01

    In this study, we investigated the role of the naturally occurring B cell-mediated T cell costimulation in the antitumor efficacy of the bispecific Ab BIS20x3. BIS20x3 has a dual specificity for both CD20 and CD3 and has previously been shown to effectively direct the lytic potential of cytolytic T

  20. CD8 T cells primed in the gut-associated lymphoid tissue induce immune-mediated cholangitis in mice.

    Science.gov (United States)

    Seidel, Daniel; Eickmeier, Ira; Kühl, Anja A; Hamann, Alf; Loddenkemper, Christoph; Schott, Eckart

    2014-02-01

    The pathogenesis of primary sclerosing cholangitis (PSC) remains poorly understood. Since PSC predominantly occurs in patients with inflammatory bowel disease, autoimmunity triggered by activated T cells migrating from the gut to the liver is a possible mechanism. We hypothesized that T cells primed in the gut-associated lymphoid tissue (GALT) by a specific antigen migrate to the liver and cause cholangitis when they recognize the same antigen on cholangiocytes. We induced ovalbumin-dependent colitis in mice that express ovalbumin in biliary epithelia (ASBT-OVA mice) and crossed ASBT-OVA mice with mice that express ovalbumin in enterocytes (iFABP-OVA mice). We analyzed T-cell activation in the GALT and crossreactivity to the same antigen in the liver as well as the effects of colitis per se on antigen-presentation and T-cell activation in the liver. Intrarectal application of ovalbumin followed by transfer of CD8 OT-I T cells led to antigen-dependent colitis. CD8 T cells primed in the GALT acquired effector function and the capability to migrate to the liver, where they caused cholangitis in a strictly antigen-dependent manner. Likewise, cholangitis developed in mice expressing ovalbumin simultaneously in biliary epithelia and enterocytes after transfer of OT-I T cells. Dextran sodium sulfate colitis led to increased levels of inflammatory cytokines in the portal venous blood, induced activation of resident liver dendritic cells, and promoted the induction of T-cell-dependent cholangitis. Our data strengthen the notion that immune-mediated cholangitis is caused by T cells primed in the GALT and provide the first link between colitis and cholangitis in an antigen-dependent mouse model. © 2013 by the American Association for the Study of Liver Diseases.

  1. Inflammatory impact of IFN-γ in CD8+ T cell-mediated lung injury is mediated by both Stat1-dependent and -independent pathways

    Science.gov (United States)

    Ramana, Chilakamarti V.; DeBerge, Matthew P.; Kumar, Aseem; Alia, Christopher S.; Durbin, Joan E.

    2015-01-01

    Influenza infection results in considerable pulmonary pathology, a significant component of which is mediated by CD8+ T cell effector functions. To isolate the specific contribution of CD8+ T cells to lung immunopathology, we utilized a nonviral murine model in which alveolar epithelial cells express an influenza antigen and injury is initiated by adoptive transfer of influenza-specific CD8+ T cells. We report that IFN-γ production by adoptively transferred influenza-specific CD8+ T cells is a significant contributor to acute lung injury following influenza antigen recognition, in isolation from its impact on viral clearance. CD8+ T cell production of IFN-γ enhanced lung epithelial cell expression of chemokines and the subsequent recruitment of inflammatory cells into the airways. Surprisingly, Stat1 deficiency in the adoptive-transfer recipients exacerbated the lung injury that was mediated by the transferred influenza-specific CD8+ T cells but was still dependent on IFN-γ production by these cells. Loss of Stat1 resulted in sustained activation of Stat3 signaling, dysregulated chemokine expression, and increased infiltration of the airways by inflammatory cells. Taken together, these data identify important roles for IFN-γ signaling and Stat1-independent IFN-γ signaling in regulating CD8+ T cell-mediated acute lung injury. This is the first study to demonstrate an anti-inflammatory effect of Stat1 on CD8+ T cell-mediated lung immunopathology without the complication of differences in viral load. PMID:25617378

  2. The new numerology of immunity mediated by virus-specific CD8(+) T cells.

    Science.gov (United States)

    Doherty, P C

    1998-08-01

    Our understanding of virus-specific CD8(+) T cell responses is currently being revolutionized by peptide-based assay systems that allow flow cytometric analysis of effector and memory cytotoxic T lymphocyte populations. These techniques are, for the first time, putting the analysis of T-cell-mediated immunity on a quantitative basis.

  3. Systemic immunological tolerance to ocular antigens is mediated by TRAIL-expressing CD8+ T cells.

    Science.gov (United States)

    Griffith, Thomas S; Brincks, Erik L; Gurung, Prajwal; Kucaba, Tamara A; Ferguson, Thomas A

    2011-01-15

    Systemic immunological tolerance to Ag encountered in the eye restricts the formation of potentially damaging immune responses that would otherwise be initiated at other anatomical locations. We previously demonstrated that tolerance to Ag administered via the anterior chamber (AC) of the eye required Fas ligand-mediated apoptotic death of inflammatory cells that enter the eye in response to the antigenic challenge. Moreover, the systemic tolerance induced after AC injection of Ag was mediated by CD8(+) regulatory T cells. This study examined the mechanism by which these CD8(+) regulatory T cells mediate tolerance after AC injection of Ag. AC injection of Ag did not prime CD4(+) T cells and led to increased TRAIL expression by splenic CD8(+) T cells. Unlike wild-type mice, Trail(-/-) or Dr5(-/-) mice did not develop tolerance to Ag injected into the eye, even though responding lymphocytes underwent apoptosis in the AC of the eyes of these mice. CD8(+) T cells from Trail(-/-) mice that were first injected via the AC with Ag were unable to transfer tolerance to naive recipient wild-type mice, but CD8(+) T cells from AC-injected wild-type or Dr5(-/-) mice could transfer tolerance. Importantly, the transferred wild-type (Trail(+/+)) CD8(+) T cells were also able to decrease the number of infiltrating inflammatory cells into the eye; however, Trail(-/-) CD8(+) T cells were unable to limit the inflammatory cell ingress. Together, our data suggest that "helpless" CD8(+) regulatory T cells generated after AC injection of Ag enforce systemic tolerance in a TRAIL-dependent manner to inhibit inflammation in the eye.

  4. Blimp-1–mediated CD4 T cell exhaustion causes CD8 T cell dysfunction during chronic toxoplasmosis

    Science.gov (United States)

    Cobb, Dustin A.; Bhadra, Rajarshi

    2016-01-01

    CD8, but not CD4, T cells are considered critical for control of chronic toxoplasmosis. Although CD8 exhaustion has been previously reported in Toxoplasma encephalitis (TE)–susceptible model, our current work demonstrates that CD4 not only become exhausted during chronic toxoplasmosis but this dysfunction is more pronounced than CD8 T cells. Exhausted CD4 population expressed elevated levels of multiple inhibitory receptors concomitant with the reduced functionality and up-regulation of Blimp-1, a transcription factor. Our data demonstrates for the first time that Blimp-1 is a critical regulator for CD4 T cell exhaustion especially in the CD4 central memory cell subset. Using a tamoxifen-dependent conditional Blimp-1 knockout mixed bone marrow chimera as well as an adoptive transfer approach, we show that CD4 T cell–intrinsic deletion of Blimp-1 reversed CD8 T cell dysfunction and resulted in improved pathogen control. To the best of our knowledge, this is a novel finding, which demonstrates the role of Blimp-1 as a critical regulator of CD4 dysfunction and links it to the CD8 T cell dysfunctionality observed in infected mice. The critical role of CD4-intrinsic Blimp-1 expression in mediating CD4 and CD8 T cell exhaustion may provide a rational basis for designing novel therapeutic approaches. PMID:27481131

  5. CD4 T cells play important roles in maintaining IL-17-producing γδ T-cell subsets in naive animals.

    Science.gov (United States)

    Do, Jeong-Su; Visperas, Anabelle; O'Brien, Rebecca L; Min, Booki

    2012-04-01

    A proportional balance between αβ and γδ T-cell subsets in the periphery is exceedingly well maintained by a homeostatic mechanism. However, a cellular mechanism underlying the regulation remains undefined. We recently reported that a subset of developing γδ T cells spontaneously acquires interleukin (IL)-17-producing capacity even within naive animals through a transforming growth factor (TGF)β1-dependent mechanism, thus considered 'innate' IL-17-producing cells. Here, we report that γδ T cells generated within αβ T cell (or CD4 T cell)-deficient environments displayed altered cytokine profiles; particularly, 'innate' IL-17 expression was significantly impaired compared with those in wild-type mice. Impaired IL-17 production in γδ T cells was directly related to CD4 T-cell deficiency, because depletion of CD4 T cells in wild-type mice diminished and adoptive CD4 T-cell transfer into T-cell receptor β-/- mice restored IL-17 expression in γδ T cells. CD4 T cell-mediated IL-17 expression required TGFβ1. Moreover, Th17 but not Th1 or Th2 effector CD4 T cells were highly efficient in enhancing γδ T-cell IL-17 expression. Taken together, our results highlight a novel CD4 T cell-dependent mechanism that shapes the generation of IL-17+ γδ T cells in naive settings.

  6. The TRPA1 ion channel is expressed in CD4+ T cells and restrains T-cell-mediated colitis through inhibition of TRPV1.

    Science.gov (United States)

    Bertin, Samuel; Aoki-Nonaka, Yukari; Lee, Jihyung; de Jong, Petrus R; Kim, Peter; Han, Tiffany; Yu, Timothy; To, Keith; Takahashi, Naoki; Boland, Brigid S; Chang, John T; Ho, Samuel B; Herdman, Scott; Corr, Maripat; Franco, Alessandra; Sharma, Sonia; Dong, Hui; Akopian, Armen N; Raz, Eyal

    2017-09-01

    Transient receptor potential ankyrin-1 (TRPA1) and transient receptor potential vanilloid-1 (TRPV1) are calcium (Ca 2+ )-permeable ion channels mostly known as pain receptors in sensory neurons. However, growing evidence suggests their crucial involvement in the pathogenesis of IBD. We explored the possible contribution of TRPA1 and TRPV1 to T-cell-mediated colitis. We evaluated the role of Trpa1 gene deletion in two models of experimental colitis (ie, interleukin-10 knockout and T-cell-adoptive transfer models). We performed electrophysiological and Ca 2+ imaging studies to analyse TRPA1 and TRPV1 functions in CD4+ T cells. We used genetic and pharmacological approaches to evaluate TRPV1 contribution to the phenotype of Trpa1 -/- CD4+ T cells. We also analysed TRPA1 and TRPV1 gene expression and TRPA1 + TRPV1 + T cell infiltration in colonic biopsies from patients with IBD. We identified a protective role for TRPA1 in T-cell-mediated colitis. We demonstrated the functional expression of TRPA1 on the plasma membrane of CD4+ T cells and identified that Trpa1 -/- CD4+ T cells have increased T-cell receptor-induced Ca 2+ influx, activation profile and differentiation into Th1-effector cells. This phenotype was abrogated upon genetic deletion or pharmacological inhibition of the TRPV1 channel in mouse and human CD4+ T cells. Finally, we found differential regulation of TRPA1 and TRPV1 gene expression as well as increased infiltration of TRPA1 + TRPV1 + T cells in the colon of patients with IBD. Our study indicates that TRPA1 inhibits TRPV1 channel activity in CD4+ T cells, and consequently restrains CD4+ T-cell activation and colitogenic responses. These findings may therefore have therapeutic implications for human IBD. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  7. Imaging TCR-Dependent NFAT-Mediated T-Cell Activation with Positron Emission Tomography In Vivo

    Directory of Open Access Journals (Sweden)

    Vladimir Ponomarev

    2001-01-01

    Full Text Available A noninvasive method for molecular imaging of T-cell activity in vivo would be of considerable value. It would aid in understanding the role of specific genes and signal transduction pathways in the course of normal and pathologic immune responses, could elucidate temporal dynamics and immune regulation at different stages of disease and following therapy. We developed and assessed a novel method for monitoring the T-cell receptor (TCR -dependent nuclear factor of activated T cells (NFAT -mediated activation of T cells by optical fluorescence imaging (OFI and positron emission tomography (PET. The herpes simplex virus type 1 thymidine kinase/green fluorescent protein [HSV1-tk/GFP (TKGFP ] dual reporter gene was used to monitor NFAT-mediated transcriptional activation in human Jurkat cells. A recombinant retrovirus bearing the NFAT-TKGFP reporter system was constructed in which the TKGFP reporter gene was placed under control of an artificial cis-acting NFAT-specific enhancer. Transduced Jurkat cells were used to establish subcutaneous infiltrates in nude rats. We demonstrated that noninvasive OR and nuclear imaging of T-cell activation is feasible using the NFAT-TKGFP reporter system. PET imaging with [124]FIAU using the NFAT-TKGFP reporter system is sufficiently sensitive to detect T-cell activation in vivo. PET images were confirmed by independent measurements of T-cell activation (e.g., CD69 and induction of GFP fluorescence. PET imaging of TCR-induced NFAT-dependent transcriptional activity may be useful in the assessment of T cell responses, T-cell-based adoptive therapies, vaccination strategies and immunosuppressive drugs.

  8. Co-Introduced Functional CCR2 Potentiates In Vivo Anti-Lung Cancer Functionality Mediated by T Cells Double Gene-Modified to Express WT1-Specific T-Cell Receptor

    Science.gov (United States)

    Asai, Hiroaki; Fujiwara, Hiroshi; An, Jun; Ochi, Toshiki; Miyazaki, Yukihiro; Nagai, Kozo; Okamoto, Sachiko; Mineno, Junichi; Kuzushima, Kiyotaka; Shiku, Hiroshi; Inoue, Hirofumi; Yasukawa, Masaki

    2013-01-01

    Background and Purpose Although gene-modification of T cells to express tumor-related antigen-specific T-cell receptor (TCR) or chimeric antigen receptor (CAR) has clinically proved promise, there still remains room to improve the clinical efficacy of re-directed T-cell based antitumor adoptive therapy. In order to achieve more objective clinical responses using ex vivo-expanded tumor-responsive T cells, the infused T cells need to show adequate localized infiltration into the tumor. Methodology/Principal Findings Human lung cancer cells variously express a tumor antigen, Wilms' Tumor gene product 1 (WT1), and an inflammatory chemokine, CCL2. However, CCR2, the relevant receptor for CCL2, is rarely expressed on activated T-lymphocytes. A HLA-A2402+ human lung cancer cell line, LK79, which expresses high amounts of both CCL2 and WT1 mRNA, was employed as a target. Normal CD8+ T cells were retrovirally gene-modified to express both CCR2 and HLA-A*2402-restricted and WT1235–243 nonapeptide-specific TCR as an effector. Anti-tumor functionality mediated by these effector cells against LK79 cells was assessed both in vitro and in vivo. Finally the impact of CCL2 on WT1 epitope-responsive TCR signaling mediated by the effector cells was studied. Introduced CCR2 was functionally validated using gene-modified Jurkat cells and human CD3+ T cells both in vitro and in vivo. Double gene-modified CD3+ T cells successfully demonstrated both CCL2-tropic tumor trafficking and cytocidal reactivity against LK79 cells in vitro and in vivo. CCL2 augmented the WT1 epitope-responsive TCR signaling shown by relevant luciferase production in double gene-modified Jurkat/MA cells to express luciferase and WT1-specific TCR, and CCL2 also dose-dependently augmented WT1 epitope-responsive IFN-γ production and CD107a expression mediated by these double gene-modifiedCD3+ T cells. Conclusion/Significance Introduction of the CCL2/CCR2 axis successfully potentiated in vivo anti-lung cancer

  9. Co-introduced functional CCR2 potentiates in vivo anti-lung cancer functionality mediated by T cells double gene-modified to express WT1-specific T-cell receptor.

    Directory of Open Access Journals (Sweden)

    Hiroaki Asai

    Full Text Available BACKGROUND AND PURPOSE: Although gene-modification of T cells to express tumor-related antigen-specific T-cell receptor (TCR or chimeric antigen receptor (CAR has clinically proved promise, there still remains room to improve the clinical efficacy of re-directed T-cell based antitumor adoptive therapy. In order to achieve more objective clinical responses using ex vivo-expanded tumor-responsive T cells, the infused T cells need to show adequate localized infiltration into the tumor. METHODOLOGY/PRINCIPAL FINDINGS: Human lung cancer cells variously express a tumor antigen, Wilms' Tumor gene product 1 (WT1, and an inflammatory chemokine, CCL2. However, CCR2, the relevant receptor for CCL2, is rarely expressed on activated T-lymphocytes. A HLA-A2402(+ human lung cancer cell line, LK79, which expresses high amounts of both CCL2 and WT1 mRNA, was employed as a target. Normal CD8(+ T cells were retrovirally gene-modified to express both CCR2 and HLA-A*2402-restricted and WT1(235-243 nonapeptide-specific TCR as an effector. Anti-tumor functionality mediated by these effector cells against LK79 cells was assessed both in vitro and in vivo. Finally the impact of CCL2 on WT1 epitope-responsive TCR signaling mediated by the effector cells was studied. Introduced CCR2 was functionally validated using gene-modified Jurkat cells and human CD3(+ T cells both in vitro and in vivo. Double gene-modified CD3(+ T cells successfully demonstrated both CCL2-tropic tumor trafficking and cytocidal reactivity against LK79 cells in vitro and in vivo. CCL2 augmented the WT1 epitope-responsive TCR signaling shown by relevant luciferase production in double gene-modified Jurkat/MA cells to express luciferase and WT1-specific TCR, and CCL2 also dose-dependently augmented WT1 epitope-responsive IFN-γ production and CD107a expression mediated by these double gene-modified CD3(+ T cells. CONCLUSION/SIGNIFICANCE: Introduction of the CCL2/CCR2 axis successfully potentiated in

  10. A colitogenic memory CD4+ T cell population mediates gastrointestinal graft-versus-host disease

    Science.gov (United States)

    Zhou, Vivian; Agle, Kimberle; Chen, Xiao; Beres, Amy; Komorowski, Richard; Belle, Ludovic; Taylor, Carolyn; Zhu, Fenlu; Haribhai, Dipica; Williams, Calvin B.; Verbsky, James; Blumenschein, Wendy; Sadekova, Svetlana; Bowman, Eddie; Ballantyne, Christie; Weaver, Casey; Serody, David A.; Vincent, Benjamin; Serody, Jonathan; Cua, Daniel J.; Drobyski, William R.

    2016-01-01

    Damage to the gastrointestinal tract is a major cause of morbidity and mortality in graft-versus-host disease (GVHD) and is attributable to T cell–mediated inflammation. In this work, we identified a unique CD4+ T cell population that constitutively expresses the β2 integrin CD11c and displays a biased central memory phenotype and memory T cell transcriptional profile, innate-like properties, and increased expression of the gut-homing molecules α4β7 and CCR9. Using several complementary murine GVHD models, we determined that adoptive transfer and early accumulation of β2 integrin–expressing CD4+ T cells in the gastrointestinal tract initiated Th1-mediated proinflammatory cytokine production, augmented pathological damage in the colon, and increased mortality. The pathogenic effect of this CD4+ T cell population critically depended on coexpression of the IL-23 receptor, which was required for maximal inflammatory effects. Non–Foxp3-expressing CD4+ T cells produced IL-10, which regulated colonic inflammation and attenuated lethality in the absence of functional CD4+Foxp3+ T cells. Thus, the coordinate expression of CD11c and the IL-23 receptor defines an IL-10–regulated, colitogenic memory CD4+ T cell subset that is poised to initiate inflammation when there is loss of tolerance and breakdown of mucosal barriers. PMID:27500496

  11. Role of very late antigen-1 in T-cell-mediated immunity to systemic viral infection

    DEFF Research Database (Denmark)

    Ørding Kauffmann, Susanne; Thomsen, Allan Randrup; Christensen, Jan Pravsgaard

    2006-01-01

    or their distribution between lymphoid and nonlymphoid organs. Regarding a functional role of VLA-1, we found that intracerebral infection of both VLA-1(-/-) and wild-type (wt) mice resulted in lethal T-cell-mediated meningitis, and quantitative and qualitative analyses of the cellular exudate did not reveal any...... significant differences between the two strains. Expression of VLA-1 was also found to be redundant regarding the ability of effector T cells to eliminate virus from internal organs of i.v. infected mice. Using delayed-type hypersensitivity (DTH) assays to evaluate subdermal CD8(+) T......, the current findings indicate that the expression of VLA-1 is not pivotal for T-cell-mediated antiviral immunity to a systemic infection....

  12. Functional cooperation between HIF-1α and c-Jun in mediating primary and acquired resistance to gefitinib in NSCLC cells with activating mutation of EGFR.

    Science.gov (United States)

    Meng, Shuyan; Wang, Guorui; Lu, Yang; Fan, Zhen

    2018-07-01

    Hypoxia-inducible factor 1 (HIF-1) and activator protein 1 (AP-1) are important transcription factors regulating expression of genes involved in cell survival. HIF-1α and c-Jun are key components of HIF-1 and AP-1, respectively, and are regulated by epidermal growth factor receptor (EGFR)-mediated cell signaling and tumor microenvironmental cues. The roles of HIF-1α and c-Jun in development of resistance to EGFR tyrosine kinase inhibitor (TKI) in non-small cell lung cancer (NSCLC) with activating mutation of EGFR have not been explored. In this study, we investigated the roles of HIF-1α and c-Jun in mediating primary and acquired resistance to gefitinib in NSCLC cells with activating mutation of EGFR. Changes in HIF-1α protein and in total and phosphorylated c-Jun levels in relation to changes in total and phosphorylated EGFR levels before and after gefitinib treatment were measured using Western blot analysis in NSCLC cells sensitive or resistant to gefitinib. The impact of overexpression of a constitutively expressed HIF-1α (HIF-1α/ΔODD) or a constitutively active c-Jun upstream regulator (SEK1 S220E/T224D mutant) on cell response to gefitinib was also examined. The effect of pharmacological inhibition of SEK1-JNK-c-Jun pathway on cell response to gefitinib was evaluated. Downregulation of HIF-1α and total and phosphorylated c-Jun levels correlated with cell inhibitory response to gefitinib better than decrease in phosphorylated EGFR did in NSCLC cells with intrinsic or acquired resistance to gefitinib. Overexpression of HIF-1α/ΔODD or SEK1 S220E/T224D mutant conferred resistance to gefitinib. There exists a positive feed-forward regulation loop between HIF-1 and c-Jun. The JNK inhibitor SP600125 sensitized gefitinib-resistant NSCLC cells to gefitinib. HIF-1α and c-Jun functionally cooperate in development of resistance to gefitinib in NSCLC cells. The translational value of inhibiting HIF-1α/c-Jun cooperation in overcoming resistance to EGFR TKI

  13. A robust and scalable TCR-based reporter cell assay to measure HIV-1 Nef-mediated T cell immune evasion.

    Science.gov (United States)

    Anmole, Gursev; Kuang, Xiaomei T; Toyoda, Mako; Martin, Eric; Shahid, Aniqa; Le, Anh Q; Markle, Tristan; Baraki, Bemuluyigza; Jones, R Brad; Ostrowski, Mario A; Ueno, Takamasa; Brumme, Zabrina L; Brockman, Mark A

    2015-11-01

    HIV-1 evades cytotoxic T cell responses through Nef-mediated downregulation of HLA class I molecules from the infected cell surface. Methods to quantify the impact of Nef on T cell recognition typically employ patient-derived T cell clones; however, these assays are limited by the cost and effort required to isolate and maintain primary cell lines. The variable activity of different T cell clones and the limited number of cells generated by re-stimulation can also hinder assay reproducibility and scalability. Here, we describe a heterologous T cell receptor reporter assay and use it to study immune evasion by Nef. Induction of NFAT-driven luciferase following co-culture with peptide-pulsed or virus-infected target cells serves as a rapid, quantitative and antigen-specific measure of T cell recognition of its cognate peptide/HLA complex. We demonstrate that Nef-mediated downregulation of HLA on target cells correlates inversely with T cell receptor-dependent luminescent signal generated by effector cells. This method provides a robust, flexible and scalable platform that is suitable for studies to measure Nef function in the context of different viral peptide/HLA antigens, to assess the function of patient-derived Nef alleles, or to screen small molecule libraries to identify novel Nef inhibitors. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. IP-10-mediated T cell homing promotes cerebral inflammation over splenic immunity to malaria infection.

    Directory of Open Access Journals (Sweden)

    Catherine Q Nie

    2009-04-01

    Full Text Available Plasmodium falciparum malaria causes 660 million clinical cases with over 2 million deaths each year. Acquired host immunity limits the clinical impact of malaria infection and provides protection against parasite replication. Experimental evidence indicates that cell-mediated immune responses also result in detrimental inflammation and contribute to severe disease induction. In both humans and mice, the spleen is a crucial organ involved in blood stage malaria clearance, while organ-specific disease appears to be associated with sequestration of parasitized erythrocytes in vascular beds and subsequent recruitment of inflammatory leukocytes. Using a rodent model of cerebral malaria, we have previously found that the majority of T lymphocytes in intravascular infiltrates of cerebral malaria-affected mice express the chemokine receptor CXCR3. Here we investigated the effect of IP-10 blockade in the development of experimental cerebral malaria and the induction of splenic anti-parasite immunity. We found that specific neutralization of IP-10 over the course of infection and genetic deletion of this chemokine in knockout mice reduces cerebral intravascular inflammation and is sufficient to protect P. berghei ANKA-infected mice from fatality. Furthermore, our results demonstrate that lack of IP-10 during infection significantly reduces peripheral parasitemia. The increased resistance to infection observed in the absence of IP-10-mediated cell trafficking was associated with retention and subsequent expansion of parasite-specific T cells in spleens of infected animals, which appears to be advantageous for the control of parasite burden. Thus, our results demonstrate that modulating homing of cellular immune responses to malaria is critical for reaching a balance between protective immunity and immunopathogenesis.

  15. Interference with Intraepithelial TNF-α Signaling Inhibits CD8+ T-Cell-Mediated Lung Injury in Influenza Infection

    OpenAIRE

    Srikiatkhachorn, Anon; Chintapalli, Jyothi; Liu, Jun; Jamaluddin, Mohammad; Harrod, Kevin S.; Whitsett, Jeffrey A.; Enelow, Richard I.; Ramana, Chilakamarti V.

    2010-01-01

    CD8+ T-cell-mediated pulmonary immunopathology in respiratory virus infection is mediated in large part by antigen-specific TNF-α expression by antiviral effector T cells, which results in epithelial chemokine expression and inflammatory infiltration of the lung. To further define the signaling events leading to lung epithelial chemokine production in response to CD8+ T-cell antigen recognition, we expressed the adenoviral 14.7K protein, a putative inhibitor of TNF-α signaling, in the distal ...

  16. Antigen-Specificity of T Cell Infiltrates in Biopsies With T Cell-Mediated Rejection and BK Polyomavirus Viremia: Analysis by Next Generation Sequencing.

    Science.gov (United States)

    Zeng, G; Huang, Y; Huang, Y; Lyu, Z; Lesniak, D; Randhawa, P

    2016-11-01

    This study interrogates the antigen-specificity of inflammatory infiltrates in renal biopsies with BK polyomavirus (BKPyV) viremia (BKPyVM) with or without allograft nephropathy (BKPyVN). Peripheral blood mononuclear cells (PBMC) from five healthy HLA-A0101 subjects were stimulated by peptides derived from the BKPYV proteome or polymorphic regions of HLA. Next generation sequencing of the T cell-receptor complementary DNA was performed on peptide-stimulated PBMC and 23 biopsies with T cell-mediated rejection (TCMR) or BKPyVN. Biopsies from patients with BKPyVM or BKVPyVN contained 7.7732 times more alloreactive than virus-reactive clones. Biopsies with TCMR also contained BKPyV-specific clones, presumably a manifestation of heterologous immunity. The mean cumulative T cell clonal frequency was 0.1378 for alloreactive clones and 0.0375 for BKPyV-reactive clones. Samples with BKPyVN and TCMR clustered separately in dendrograms of V-family and J-gene utilization patterns. Dendrograms also revealed that V-gene, J-gene, and D-gene usage patterns were a function of HLA type. In conclusion, biopsies with BKPyVN contain abundant allospecific clones that exceed the number of virus-reactive clones. The T cell component of tissue injury in viral nephropathy appears to be mediated primarily by an "innocent bystander" mechanism in which the principal element is secondary T cell influx triggered by both antiviral and anti-HLA immunity. © Copyright 2016 The American Society of Transplantation and the American Society of Transplant Surgeons.

  17. CD4 T cells mediate both positive and negative regulation of the immune response to HIV infection: complex role of T follicular helper cells and Regulatory T cells in pathogenesis

    Directory of Open Access Journals (Sweden)

    Chansavath ePhetsouphanh

    2015-01-01

    Full Text Available HIV-1 infection results in chronic activation of cells in lymphoid tissue, including T cells, B cells and myeloid lineage cells. The resulting characteristic hyperplasia is an amalgam of proliferating host immune cells in the adaptive response, increased concentrations of innate response mediators due to viral and bacterial products, and homeostatic responses to inflammation. While it is generally thought that CD4 T cells are greatly depleted, in fact, two types of CD4 T cells appear to be increased, namely regulatory T cells (Tregs and T follicular helper cells (Tfh. These cells have opposing roles, but may both be important in the pathogenic process. Whether Tregs are failing in their role to limit lymphocyte activation is unclear, but there is no doubt now that Tfh are associated with B cell hyperplasia and increased germinal centre activity. Antiretroviral therapy (ART may reduce the lymphocyte activation, but not completely, and therefore there is a need for interventions that selectively enhance normal CD4 function without exacerbating Tfh, B cell or Treg dysfunction.

  18. A new sensitive and quantitative HTLV-I-mediated cell fusion assay in T cells

    International Nuclear Information System (INIS)

    Pare, Marie-Eve; Gauthier, Sonia; Landry, Sebastien; Sun Jiangfeng; Legault, Eric; Leclerc, Denis; Tanaka, Yuetsu; Marriott, Susan J.; Tremblay, Michel J.; Barbeau, Benoit

    2005-01-01

    Similar to several other viruses, human T cell leukemia virus type I (HTLV-I) induces the formation of multinucleated giant cells (also known as syncytium) when amplified in tissue culture. These syncytia result from the fusion of infected cells with uninfected cells. Due to the intrinsic difficulty of infecting cells with cell-free HTLV-I virions, syncytium formation has become an important tool in the study of HTLV-I infection and transmission. Since most HTLV-I-based cell fusion assays rely on the use of non-T cells, the aim of this study was to optimize a new HTLV-I-induced cell fusion assay in which HTLV-I-infected T cell lines are co-cultured with T cells that have been transfected with an HTLV-I long terminal repeat (LTR) luciferase reporter construct. We demonstrate that co-culture of various HTLV-I-infected T cells with different transfected T cell lines resulted in induction of luciferase activity. Cell-to-cell contact and expression of the viral gp46 envelope protein was crucial for this induction while other cell surface proteins (including HSC70) did not have a significant effect. This quantitative assay was shown to be very sensitive. In this assay, the cell fusion-mediated activation of NF-κB and the HTLV-I LTR occurred through previously described Tax-dependent signaling pathways. This assay also showed that cell fusion could activate Tax-inducible cellular promoters. These results thus demonstrate that this new quantitative HTLV-I-dependent cell fusion assay is versatile, highly sensitive, and can provide an important tool to investigate cellular promoter activation and intrinsic signaling cascades that modulate cellular gene expression

  19. Microenvironmental cues enhance mesenchymal stem cell-mediated immunomodulation and regulatory T-cell expansion.

    Science.gov (United States)

    Kadle, Rohini L; Abdou, Salma A; Villarreal-Ponce, Alvaro P; Soares, Marc A; Sultan, Darren L; David, Joshua A; Massie, Jonathan; Rifkin, William J; Rabbani, Piul; Ceradini, Daniel J

    2018-01-01

    Mesenchymal stem cells (MSCs) are known to both have powerful immunosuppressive properties and promote allograft tolerance. Determining the environmental oxygen tension and inflammatory conditions under which MSCs are optimally primed for this immunosuppressive function is essential to their utilization in promoting graft tolerance. Of particular interest is the mechanisms governing the interaction between MSCs and regulatory T cells (Tregs), which is relatively unknown. We performed our experiments utilizing rat bone marrow derived MSCs. We observed that priming MSCs in hypoxia promotes maintenance of stem-like characteristics, with greater expression of typical MSC cell-surface markers, increased proliferation, and maintenance of differentiation potential. Addition of autologous MSCs to CD4+/allogeneic endothelial cell (EC) co-culture increases regulatory T cell (Treg) proliferation, which is further enhanced when MSCs are primed in hypoxia. Furthermore, MSC-mediated Treg expansion does not require direct cell-cell contact. The expression of indolamine 2,3-dioxygenase, a mediator of MSC immunomodulation, increases when MSCs are primed in hypoxia, and inhibition of IDO significantly decreases the expansion of Tregs. Priming with inflammatory cytokines IFNγ and TNFα increases also expression of markers associated with MSC immunomodulatory function, but decreases MSC proliferation. The expression of IDO also increases when MSCs are primed with inflammatory cytokines. However, there is no increase in Treg expansion when MSCs are primed with IFNγ, suggesting an alternate mechanism for inflammatory-stimulated MSC immunomodulation. Overall, these results suggest that MSCs primed in hypoxia or inflammatory conditions are optimally primed for immunosuppressive function. These results provide a clearer picture of how to enhance MSC immunomodulation for clinical use.

  20. The role of acquired immunity and periodontal disease progression.

    Science.gov (United States)

    Teng, Yen-Tung A

    2003-01-01

    Our understanding of the pathogenesis in human periodontal diseases is limited by the lack of specific and sensitive tools or models to study the complex microbial challenges and their interactions with the host's immune system. Recent advances in cellular and molecular biology research have demonstrated the importance of the acquired immune system not only in fighting the virulent periodontal pathogens but also in protecting the host from developing further devastating conditions in periodontal infections. The use of genetic knockout and immunodeficient mouse strains has shown that the acquired immune response-in particular, CD4+ T-cells-plays a pivotal role in controlling the ongoing infection, the immune/inflammatory responses, and the subsequent host's tissue destruction. In particular, studies of the pathogen-specific CD4+ T-cell-mediated immunity have clarified the roles of: (i) the relative diverse immune repertoire involved in periodontal pathogenesis, (ii) the contribution of pathogen-associated Th1-Th2 cytokine expressions in periodontal disease progression, and (iii) micro-organism-triggered periodontal CD4+ T-cell-mediated osteoclastogenic factor, 'RANK-L', which is linked to the induction of alveolar bone destruction in situ. The present review will focus on some recent advances in the acquired immune responses involving B-cells, CD8+ T-cells, and CD4+ T-cells in the context of periodontal disease progression. New approaches will further facilitate our understanding of their underlying molecular mechanisms that may lead to the development of new treatment modalities for periodontal diseases and their associated complications.

  1. TNFα and IFNγ but not perforin are critical for CD8 T cell-mediated protection against pulmonary Yersinia pestis infection.

    Science.gov (United States)

    Szaba, Frank M; Kummer, Lawrence W; Duso, Debra K; Koroleva, Ekaterina P; Tumanov, Alexei V; Cooper, Andrea M; Bliska, James B; Smiley, Stephen T; Lin, Jr-Shiuan

    2014-05-01

    Septic pneumonias resulting from bacterial infections of the lung are a leading cause of human death worldwide. Little is known about the capacity of CD8 T cell-mediated immunity to combat these infections and the types of effector functions that may be most effective. Pneumonic plague is an acutely lethal septic pneumonia caused by the Gram-negative bacterium Yersinia pestis. We recently identified a dominant and protective Y. pestis antigen, YopE69-77, recognized by CD8 T cells in C57BL/6 mice. Here, we use gene-deficient mice, Ab-mediated depletion, cell transfers, and bone marrow chimeric mice to investigate the effector functions of YopE69-77-specific CD8 T cells and their relative contributions during pulmonary Y. pestis infection. We demonstrate that YopE69-77-specific CD8 T cells exhibit perforin-dependent cytotoxicity in vivo; however, perforin is dispensable for YopE69-77-mediated protection. In contrast, YopE69-77-mediated protection is severely impaired when production of TNFα and IFNγ by CD8 T cells is simultaneously ablated. Interestingly, TNFα is absolutely required at the time of challenge infection and can be provided by either T cells or non-T cells, whereas IFNγ provided by T cells prior to challenge appears to facilitate the differentiation of optimally protective CD8 T cells. We conclude that cytokine production, not cytotoxicity, is essential for CD8 T cell-mediated control of pulmonary Y. pestis infection and we suggest that assays detecting Ag-specific TNFα production in addition to antibody titers may be useful correlates of vaccine efficacy against plague and other acutely lethal septic bacterial pneumonias.

  2. Endogenous n-3 polyunsaturated fatty acids attenuate T cell-mediated hepatitis via autophagy activation

    Directory of Open Access Journals (Sweden)

    Yanli Li

    2016-09-01

    Full Text Available Omega-3 polyunsaturated fatty acids (n-3 PUFAs exert anti-inflammatory effects in several liver disorders, including cirrhosis, acute liver failure, and fatty liver disease. To date, little is known about their role in immune-mediated liver diseases. In this study, we used fat-1 transgenic mice rich in endogenous n-3 PUFAs to examine the role of n-3 PUFAs in immune-mediated liver injury. Concanavalin A (Con A was administered intravenously to wild-type (WT and fat-1 transgenic mice to induce T cell-mediated hepatitis. Reduced liver damage was shown in Con A-administrated fat-1 transgenic mice, as evidenced by decreased mortality, attenuated hepatic necrosis, lessened serum alanine aminotransferase (ALT activity, and inhibited production of pro-inflammatory cytokines (e.g. TNF-α, IL-6, IL-17A and IFN-γ. In vivo and in vitro studies demonstrated that n-3 PUFAs significantly inhibited the activation of hepatic T cells and the differentiation of Th1 cells after Con A challenge. Further studies showed that n-3 PUFAs markedly increased autophagy level in Con A-treated fat-1 T cells compared with the WT counterparts. Blocking hepatic autophagy activity with chloroquine diminished the differences in T cell activation and liver injury between Con A-injected WT and fat-1 transgenic mice. We conclude that n-3 PUFAs limit Con A-induced hepatitis via an autophagy-dependent mechanism, and could be exploited as a new therapeutic approach for autoimmune hepatitis.

  3. IFN-Gamma-Dependent and Independent Mechanisms of CD4+ Memory T Cell-Mediated Protection from Listeria Infection

    Directory of Open Access Journals (Sweden)

    Stephanie M. Meek

    2018-02-01

    Full Text Available While CD8+ memory T cells can promote long-lived protection from secondary exposure to intracellular pathogens, less is known regarding the direct protective mechanisms of CD4+ T cells. We utilized a prime/boost model in which mice are initially exposed to an acutely infecting strain of lymphocytic choriomeningitis virus (LCMV, followed by a heterologous rechallenge with Listeria monocytogenes recombinantly expressing the MHC Class II-restricted LCMV epitope, GP61–80 (Lm-gp61. We found that heterologous Lm-gp61 rechallenge resulted in robust activation of CD4+ memory T cells and that they were required for rapid bacterial clearance. We further assessed the relative roles of TNF and IFNγ in the direct anti-bacterial function of CD4+ memory T cells. We found that disruption of TNF resulted in a complete loss of protection mediated by CD4+ memory T cells, whereas disruption of IFNγ signaling to macrophages results in only a partial loss of protection. The protective effect mediated by CD4+ T cells corresponded to the rapid accumulation of pro-inflammatory macrophages in the spleen and an altered inflammatory environment in vivo. Overall, we conclude that protection mediated by CD4+ memory T cells from heterologous Listeria challenge is most directly dependent on TNF, whereas IFNγ only plays a minor role.

  4. Two separate defects affecting true naive or virtual memory T cell precursors combine to reduce naive T cell responses with aging.

    Science.gov (United States)

    Renkema, Kristin R; Li, Gang; Wu, Angela; Smithey, Megan J; Nikolich-Žugich, Janko

    2014-01-01

    Naive T cell responses are eroded with aging. We and others have recently shown that unimmunized old mice lose ≥ 70% of Ag-specific CD8 T cell precursors and that many of the remaining precursors acquire a virtual (central) memory (VM; CD44(hi)CD62L(hi)) phenotype. In this study, we demonstrate that unimmunized TCR transgenic (TCRTg) mice also undergo massive VM conversion with age, exhibiting rapid effector function upon both TCR and cytokine triggering. Age-related VM conversion in TCRTg mice directly depended on replacement of the original TCRTg specificity by endogenous TCRα rearrangements, indicating that TCR signals must be critical in VM conversion. Importantly, we found that VM conversion had adverse functional effects in both old wild-type and old TCRTg mice; that is, old VM, but not old true naive, T cells exhibited blunted TCR-mediated, but not IL-15-mediated, proliferation. This selective proliferative senescence correlated with increased apoptosis in old VM cells in response to peptide, but decreased apoptosis in response to homeostatic cytokines IL-7 and IL-15. Our results identify TCR as the key factor in differential maintenance and function of Ag-specific precursors in unimmunized mice with aging, and they demonstrate that two separate age-related defects--drastic reduction in true naive T cell precursors and impaired proliferative capacity of their VM cousins--combine to reduce naive T cell responses with aging.

  5. Generation of TCR-Expressing Innate Lymphoid-like Helper Cells that Induce Cytotoxic T Cell-Mediated Anti-leukemic Cell Response.

    Science.gov (United States)

    Ueda, Norihiro; Uemura, Yasushi; Zhang, Rong; Kitayama, Shuichi; Iriguchi, Shoichi; Kawai, Yohei; Yasui, Yutaka; Tatsumi, Minako; Ueda, Tatsuki; Liu, Tian-Yi; Mizoro, Yasutaka; Okada, Chihiro; Watanabe, Akira; Nakanishi, Mahito; Senju, Satoru; Nishimura, Yasuharu; Kuzushima, Kiyotaka; Kiyoi, Hitoshi; Naoe, Tomoki; Kaneko, Shin

    2018-06-05

    CD4 + T helper (Th) cell activation is essential for inducing cytotoxic T lymphocyte (CTL) responses against malignancy. We reprogrammed a Th clone specific for chronic myelogenous leukemia (CML)-derived b3a2 peptide to pluripotency and re-differentiated the cells into original TCR-expressing T-lineage cells (iPS-T cells) with gene expression patterns resembling those of group 1 innate lymphoid cells. CD4 gene transduction into iPS-T cells enhanced b3a2 peptide-specific responses via b3a2 peptide-specific TCR. iPS-T cells upregulated CD40 ligand (CD40L) expression in response to interleukin-2 and interleukin-15. In the presence of Wilms tumor 1 (WT1) peptide, antigen-specific dendritic cells (DCs) conditioned by CD4-modified CD40L high iPS-T cells stimulated WT1-specific CTL priming, which eliminated WT1 peptide-expressing CML cells in vitro and in vivo. Thus, CD4 modification of CD40L high iPS-T cells generates innate lymphoid helper-like cells inducing bcr-abl-specific TCR signaling that mediates effectiveanti-leukemic CTL responses via DC maturation, showing potential for adjuvant immunotherapy against leukemia. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  6. Pharmacologic suppression of target cell recognition by engineered T cells expressing chimeric T-cell receptors.

    Science.gov (United States)

    Alvarez-Vallina, L; Yañez, R; Blanco, B; Gil, M; Russell, S J

    2000-04-01

    Adoptive therapy with autologous T cells expressing chimeric T-cell receptors (chTCRs) is of potential interest for the treatment of malignancy. To limit possible T-cell-mediated damage to normal tissues that weakly express the targeted tumor antigen (Ag), we have tested a strategy for the suppression of target cell recognition by engineered T cells. Jurkat T cells were transduced with an anti-hapten chTCR tinder the control of a tetracycline-suppressible promoter and were shown to respond to Ag-positive (hapten-coated) but not to Ag-negative target cells. The engineered T cells were then reacted with hapten-coated target cells at different effector to target cell ratios before and after exposure to tetracycline. When the engineered T cells were treated with tetracycline, expression of the chTCR was greatly decreased and recognition of the hapten-coated target cells was completely suppressed. Tetracycline-mediated suppression of target cell recognition by engineered T cells may be a useful strategy to limit the toxicity of the approach to cancer gene therapy.

  7. Strategy for eliciting antigen-specific CD8+ T cell-mediated immune response against a cryptic CTL epitope of merkel cell polyomavirus large T antigen

    Directory of Open Access Journals (Sweden)

    Gomez Bianca P

    2012-10-01

    Full Text Available Abstract Background Merkel cell carcinoma (MCC is a relatively new addition to the expanding category of oncovirus-induced cancers. Although still comparably rare, the number of cases has risen dramatically in recent years. Further complicating this trend is that MCC is an extremely aggressive neoplasm with poor patient prognosis and limited treatment options for advanced disease. The causative agent of MCC has been identified as the merkel cell polyomavirus (MCPyV. The MCPyV-encoded large T (LT antigen is an oncoprotein that is theorized to be essential for virus-mediated tumorigenesis and is therefore, an excellent MCC antigen for the generation of antitumor immune responses. As a foreign antigen, the LT oncoprotein avoids the obstacle of immune tolerance, which normally impedes the development of antitumor immunity. Ergo, it is an excellent target for anti-MCC immunotherapy. Since tumor-specific CD8+ T cells lead to better prognosis for MCC and numerous other cancers, we have generated a DNA vaccine that is capable of eliciting LT-specific CD8+ T cells. The DNA vaccine (pcDNA3-CRT/LT encodes the LT antigen linked to a damage-associated molecular pattern, calreticulin (CRT, as it has been demonstrated that the linkage of CRT to antigens promotes the induction of antigen-specific CD8+ T cells. Results The present study shows that DNA vaccine-induced generation of LT-specific CD8+ T cells is augmented by linking CRT to the LT antigen. This is relevant since the therapeutic effects of the pcDNA3-CRT/LT DNA vaccine is mediated by LT-specific CD8+ T cells. Mice vaccinated with the DNA vaccine produced demonstrably more LT-specific CD8+ T cells. The DNA vaccine was also able to confer LT-specific CD8+ T cell-mediated protective and therapeutic effects to prolong the survival of mice with LT-expressing tumors. In the interest of determining the LT epitope which most MCC-specific CD8+ T cells recognize, we identified the amino acid sequence of the

  8. PRMT5 Is Upregulated in HTLV-1-Mediated T-Cell Transformation and Selective Inhibition Alters Viral Gene Expression and Infected Cell Survival

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    Amanda R. Panfil

    2015-12-01

    Full Text Available Human T-cell leukemia virus type-1 (HTLV-1 is a tumorigenic retrovirus responsible for development of adult T-cell leukemia/lymphoma (ATLL. This disease manifests after a long clinical latency period of up to 2–3 decades. Two viral gene products, Tax and HBZ, have transforming properties and play a role in the pathogenic process. Genetic and epigenetic cellular changes also occur in HTLV-1-infected cells, which contribute to transformation and disease development. However, the role of cellular factors in transformation is not completely understood. Herein, we examined the role of protein arginine methyltransferase 5 (PRMT5 on HTLV-1-mediated cellular transformation and viral gene expression. We found PRMT5 expression was upregulated during HTLV-1-mediated T-cell transformation, as well as in established lymphocytic leukemia/lymphoma cell lines and ATLL patient PBMCs. shRNA-mediated reduction in PRMT5 protein levels or its inhibition by a small molecule inhibitor (PRMT5i in HTLV-1-infected lymphocytes resulted in increased viral gene expression and decreased cellular proliferation. PRMT5i also had selective toxicity in HTLV-1-transformed T-cells. Finally, we demonstrated that PRMT5 and the HTLV-1 p30 protein had an additive inhibitory effect on HTLV-1 gene expression. Our study provides evidence for PRMT5 as a host cell factor important in HTLV-1-mediated T-cell transformation, and a potential target for ATLL treatment.

  9. Intrathymic laminin-mediated interactions: role in T cell migration and development

    Directory of Open Access Journals (Sweden)

    Wilson eSavino

    2015-11-01

    Full Text Available Intrathymic T cell differentiation is a key process for the development and maintenance of cell-mediated immunity, and occurs concomitantly to highly regulated migratory events. We have proposed a multivectorial model for describing intrathymic thymocyte migration. One of the individual vectors comprises interactions mediated by laminins, a heterotrimeric protein family of the extracellular matrix. Several laminins are expressed in the thymus, being produced by microenvironmental cells, particularly thymic epithelial cells. Also, thymocytes and epithelial cells express integrin-type laminin receptors. Functionally, it has been reported that the dy/dy mutant mouse (lacking the laminin isoform 211 exhibits defective thymocyte differentiation. Several data show haptotactic effects of laminins upon thymocytes, as well as their adhesion on thymic epithelial cells; both effects being prevented by anti-laminin or anti-laminin receptor antibodies. Interestingly, laminin synergizes with chemokines to enhance thymocyte migration, whereas classe-3 semaphorins and B ephrins, which exhibit chemorepulsive effects in the thymus, downregulate laminin-mediated migratory responses of thymocytes. More recently, we showed that knocking down the ITGA6 gene (which encodes the α6 integrin chain of laminin receptors in human thymic epithelial cells, modulates a large number of cell-migration related genes, and results in changes of adhesion pattern of thymocytes onto the thymic epithelium. Overall, laminin-mediated interactions can be placed at the cross-road of the multivectorial process of thymocyte migration, with a direct influence per se, as well as by modulating other molecular interactions associated with the intrathymic trafficking events.

  10. Downregulation of IL-12 and a novel negative feedback system mediated by CD25+CD4+ T cells

    International Nuclear Information System (INIS)

    Sato, Kojiro; Tateishi, Shoko; Kubo, Kanae; Mimura, Toshihide; Yamamoto, Kazuhiko; Kanda, Hiroko

    2005-01-01

    CD25 + CD4 + regulatory T cells suppress immune responses and are believed to play roles in preventing autoimmune diseases. However, the mechanism(s) underlying the suppression and the regulation of their homeostasis remain to be elucidated. Here we show that these regulatory T cells downregulated CD25 - CD4 + T-cell-mediated production of IL-12 from antigen-presenting cells, which can act as a growth factor for CD25 - CD4 + T cells. We further found that CD25 + CD4 + T cells, despite their well-documented 'anergic' nature, proliferate significantly in vitro only when CD25 - CD4 + T cells are present. Notably, this proliferation was strongly dependent on IL-2 and relatively independent of IL-12. Thus, CD25 + CD4 + T cells suppress CD25 - CD4 + T-cell responses, at least in part, by inhibiting IL-12 production while they themselves can undergo proliferation with the mediation of CD25 - CD4 + T cells in vitro. These results offer a novel negative feedback system involving a tripartite interaction among CD25 + CD4 + and CD25 - CD4 + T cells, and APCs that may contribute to the termination of immune responses

  11. CD301b⁺ dermal dendritic cells drive T helper 2 cell-mediated immunity.

    Science.gov (United States)

    Kumamoto, Yosuke; Linehan, Melissa; Weinstein, Jason S; Laidlaw, Brian J; Craft, Joseph E; Iwasaki, Akiko

    2013-10-17

    Unlike other types of T helper (Th) responses, whether the development of Th2 cells requires instruction from particular subset of dendritic cells (DCs) remains unclear. By using an in vivo depletion approach, we have shown that DCs expressing CD301b were required for the generation of Th2 cells after subcutaneous immunization with ovalbumin (OVA) along with papain or alum. CD301b⁺ DCs are distinct from epidermal or CD207⁺ dermal DCs (DDCs) and were responsible for transporting antigen injected subcutaneously with Th2-type adjuvants. Transient depletion of CD301b⁺ DCs resulted in less effective accumulation and decreased expression of CD69 by polyclonal CD4⁺ T cells in the lymph node. Moreover, despite intact cell division and interferon-γ production, CD301b⁺ DC depletion led to blunted interleukin-4 production by OVA-specific OT-II transgenic CD4⁺ T cells and significantly impaired Th2 cell development upon infection with Nippostrongylus brasiliensis. These results reveal CD301b⁺ DDCs as the key mediators of Th2 immunity. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. An Acquired HER2T798I Gatekeeper Mutation Induces Resistance to Neratinib in a Patient with HER2 Mutant-Driven Breast Cancer.

    Science.gov (United States)

    Hanker, Ariella B; Brewer, Monica Red; Sheehan, Jonathan H; Koch, James P; Sliwoski, Gregory R; Nagy, Rebecca; Lanman, Richard; Berger, Michael F; Hyman, David M; Solit, David B; He, Jie; Miller, Vincent; Cutler, Richard E; Lalani, Alshad S; Cross, Darren; Lovly, Christine M; Meiler, Jens; Arteaga, Carlos L

    2017-06-01

    We report a HER2 T798I gatekeeper mutation in a patient with HER2 L869R -mutant breast cancer with acquired resistance to neratinib. Laboratory studies suggested that HER2 L869R is a neratinib-sensitive, gain-of-function mutation that upon dimerization with mutant HER3 E928G , also present in the breast cancer, amplifies HER2 signaling. The patient was treated with neratinib and exhibited a sustained partial response. Upon clinical progression, HER2 T798I was detected in plasma tumor cell-free DNA. Structural modeling of this acquired mutation suggested that the increased bulk of isoleucine in HER2 T798I reduces neratinib binding. Neratinib blocked HER2-mediated signaling and growth in cells expressing HER2 L869R but not HER2 L869R/T798I In contrast, afatinib and the osimertinib metabolite AZ5104 strongly suppressed HER2 L869R/T798I -induced signaling and cell growth. Acquisition of HER2 T798I upon development of resistance to neratinib in a breast cancer with an initial activating HER2 mutation suggests HER2 L869R is a driver mutation. HER2 T798I -mediated neratinib resistance may be overcome by other irreversible HER2 inhibitors like afatinib. Significance: We found an acquired HER2 gatekeeper mutation in a patient with HER2 -mutant breast cancer upon clinical progression on neratinib. We speculate that HER2 T798I may arise as a secondary mutation following response to effective HER2 tyrosine kinase inhibitors (TKI) in other cancers with HER2 -activating mutations. This resistance may be overcome by other irreversible HER2 TKIs, such as afatinib. Cancer Discov; 7(6); 575-85. ©2017 AACR. This article is highlighted in the In This Issue feature, p. 539 . ©2017 American Association for Cancer Research.

  13. Endogenous Tim-1 (Kim-1) promotes T-cell responses and cell-mediated injury in experimental crescentic glomerulonephritis.

    Science.gov (United States)

    Nozaki, Yuji; Nikolic-Paterson, David J; Snelgrove, Sarah L; Akiba, Hisaya; Yagita, Hideo; Holdsworth, Stephen R; Kitching, A Richard

    2012-05-01

    The T-cell immunoglobulin mucin 1 (Tim-1) modulates CD4(+) T-cell responses and is also expressed by damaged proximal tubules in the kidney where it is known as kidney injury molecule-1 (Kim-1). We sought to define the role of endogenous Tim-1 in experimental T-cell-mediated glomerulonephritis induced by sheep anti-mouse glomerular basement membrane globulin acting as a planted foreign antigen. Tim-1 is expressed by infiltrating activated CD4(+) cells in this model, and we studied the effects of an inhibitory anti-Tim-1 antibody (RMT1-10) on immune responses and glomerular disease. Crescentic glomerulonephritis, proliferative injury, and leukocyte accumulation were attenuated following treatment with anti-Tim-1 antibodies, but interstitial foxp3(+) cell accumulation and interleukin-10 mRNA were increased. T-cell proliferation and apoptosis decreased in the immune system along with a selective reduction in Th1 and Th17 cellular responses both in the immune system and within the kidney. The urinary excretion and renal expression of Kim-1 was reduced by anti-Tim-1 antibodies reflecting diminished interstitial injury. The effects of anti-Tim-1 antibodies were not apparent in the early phase of renal injury, when the immune response to sheep globulin was developing. Thus, endogenous Tim-1 promotes Th1 and Th17 nephritogenic immune responses and its neutralization reduces renal injury while limiting inflammation in cell-mediated glomerulonephritis.

  14. CD83 Antibody Inhibits Human B Cell Responses to Antigen as well as Dendritic Cell-Mediated CD4 T Cell Responses.

    Science.gov (United States)

    Wong, Kuan Y; Baron, Rebecca; Seldon, Therese A; Jones, Martina L; Rice, Alison M; Munster, David J

    2018-05-15

    Anti-CD83 Ab capable of Ab-dependent cellular cytotoxicity can deplete activated CD83 + human dendritic cells, thereby inhibiting CD4 T cell-mediated acute graft-versus-host disease. As CD83 is also expressed on the surface of activated B lymphocytes, we hypothesized that anti-CD83 would also inhibit B cell responses to stimulation. We found that anti-CD83 inhibited total IgM and IgG production in vitro by allostimulated human PBMC. Also, Ag-specific Ab responses to immunization of SCID mice xenografted with human PBMC were inhibited by anti-CD83 treatment. This inhibition occurred without depletion of all human B cells because anti-CD83 lysed activated CD83 + B cells by Ab-dependent cellular cytotoxicity and spared resting (CD83 - ) B cells. In cultured human PBMC, anti-CD83 inhibited tetanus toxoid-stimulated B cell proliferation and concomitant dendritic cell-mediated CD4 T cell proliferation and expression of IFN-γ and IL-17A, with minimal losses of B cells (80% of B cells but had no effect on CD4 T cell proliferation and cytokine expression. By virtue of the ability of anti-CD83 to selectively deplete activated, but not resting, B cells and dendritic cells, with the latter reducing CD4 T cell responses, anti-CD83 may be clinically useful in autoimmunity and transplantation. Advantages might include inhibited expansion of autoantigen- or alloantigen-specific B cells and CD4 T cells, thus preventing further production of pathogenic Abs and inflammatory cytokines while preserving protective memory and regulatory cells. Copyright © 2018 by The American Association of Immunologists, Inc.

  15. Neuron-mediated generation of regulatory T cells from encephalitogenic T cells suppresses EAE

    DEFF Research Database (Denmark)

    Liu, Yawei; Teige, Ingrid; Birnir, Bryndis

    2006-01-01

    Neurons have been neglected as cells with a major immune-regulatory function because they do not express major histocompatibility complex class II. Our data show that neurons are highly immune regulatory, having a crucial role in governing T-cell response and central nervous system (CNS) inflamma......Neurons have been neglected as cells with a major immune-regulatory function because they do not express major histocompatibility complex class II. Our data show that neurons are highly immune regulatory, having a crucial role in governing T-cell response and central nervous system (CNS......) inflammation. Neurons induce the proliferation of activated CD4+ T cells through B7-CD28 and transforming growth factor (TGF)-beta1-TGF-beta receptor signaling pathways, resulting in amplification of T-cell receptor signaling through phosphorylated ZAP-70, interleukin (IL)-2 and IL-9. The interaction between...... neurons and T cells results in the conversion of encephalitogenic T cells to CD25+ TGF-beta1+ CTLA-4+ FoxP3+ T regulatory (Treg) cells that suppress encephalitogenic T cells and inhibit experimental autoimmune encephalomyelitis. Suppression is dependent on cytotoxic T lymphocyte antigen (CTLA)-4...

  16. The inhibition of human T cell proliferation by the caspase inhibitor z-VAD-FMK is mediated through oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Rajah, T.; Chow, S.C., E-mail: chow.sek.chuen@monash.edu

    2014-07-15

    The caspase inhibitor benzyloxycarbony (Cbz)-L-Val-Ala-Asp (OMe)-fluoromethylketone (z-VAD-FMK) has recently been shown to inhibit T cell proliferation without blocking caspase-8 and caspase-3 activation in primary T cells. We showed in this study that z-VAD-FMK treatment leads to a decrease in intracellular glutathione (GSH) with a concomitant increase in reactive oxygen species (ROS) levels in activated T cells. The inhibition of anti-CD3-mediated T cell proliferation induced by z-VAD-FMK was abolished by the presence of low molecular weight thiols such as GSH, N-acetylcysteine (NAC) and L-cysteine, whereas D-cysteine which cannot be metabolised to GSH has no effect. These results suggest that the depletion of intracellular GSH is the underlying cause of z-VAD-FMK-mediated inhibition of T cell activation and proliferation. The presence of exogenous GSH also attenuated the inhibition of anti-CD3-induced CD25 and CD69 expression mediated by z-VAD-FMK. However, none of the low molecular weight thiols were able to restore the caspase-inhibitory properties of z-VAD-FMK in activated T cells where caspase-8 and caspase-3 remain activated and processed into their respective subunits in the presence of the caspase inhibitor. This suggests that the inhibition of T cell proliferation can be uncoupled from the caspase-inhibitory properties of z-VAD-FMK. Taken together, the immunosuppressive effects in primary T cells mediated by z-VAD-FMK are due to oxidative stress via the depletion of GSH.

  17. The inhibition of human T cell proliferation by the caspase inhibitor z-VAD-FMK is mediated through oxidative stress

    International Nuclear Information System (INIS)

    Rajah, T.; Chow, S.C.

    2014-01-01

    The caspase inhibitor benzyloxycarbony (Cbz)-L-Val-Ala-Asp (OMe)-fluoromethylketone (z-VAD-FMK) has recently been shown to inhibit T cell proliferation without blocking caspase-8 and caspase-3 activation in primary T cells. We showed in this study that z-VAD-FMK treatment leads to a decrease in intracellular glutathione (GSH) with a concomitant increase in reactive oxygen species (ROS) levels in activated T cells. The inhibition of anti-CD3-mediated T cell proliferation induced by z-VAD-FMK was abolished by the presence of low molecular weight thiols such as GSH, N-acetylcysteine (NAC) and L-cysteine, whereas D-cysteine which cannot be metabolised to GSH has no effect. These results suggest that the depletion of intracellular GSH is the underlying cause of z-VAD-FMK-mediated inhibition of T cell activation and proliferation. The presence of exogenous GSH also attenuated the inhibition of anti-CD3-induced CD25 and CD69 expression mediated by z-VAD-FMK. However, none of the low molecular weight thiols were able to restore the caspase-inhibitory properties of z-VAD-FMK in activated T cells where caspase-8 and caspase-3 remain activated and processed into their respective subunits in the presence of the caspase inhibitor. This suggests that the inhibition of T cell proliferation can be uncoupled from the caspase-inhibitory properties of z-VAD-FMK. Taken together, the immunosuppressive effects in primary T cells mediated by z-VAD-FMK are due to oxidative stress via the depletion of GSH

  18. Exacerbation of spontaneous autoimmune nephritis following regulatory T cell depletion in B cell lymphoma 2-interacting mediator knock-out mice.

    Science.gov (United States)

    Wang, Y M; Zhang, G Y; Wang, Y; Hu, M; Zhou, J J; Sawyer, A; Cao, Q; Wang, Y; Zheng, G; Lee, V W S; Harris, D C H; Alexander, S I

    2017-05-01

    Regulatory T cells (T regs ) have been recognized as central mediators for maintaining peripheral tolerance and limiting autoimmune diseases. The loss of T regs or their function has been associated with exacerbation of autoimmune disease. However, the temporary loss of T regs in the chronic spontaneous disease model has not been investigated. In this study, we evaluated the role of T regs in a novel chronic spontaneous glomerulonephritis model of B cell lymphoma 2-interacting mediator (Bim) knock-out mice by transient depleting T regs . Bim is a pro-apoptotic member of the B cell lymphoma 2 (Bcl-2) family. Bim knock-out (Bim -/- ) mice fail to delete autoreactive T cells in thymus, leading to chronic spontaneous autoimmune kidney disease. We found that T reg depletion in Bim -/- mice exacerbated the kidney injury with increased proteinuria, impaired kidney function, weight loss and greater histological injury compared with wild-type mice. There was a significant increase in interstitial infiltrate of inflammatory cells, antibody deposition and tubular damage. Furthermore, the serum levels of cytokines interleukin (IL)-2, IL-4, IL-6, IL-10, IL-17α, interferon (IFN)-γ and tumour necrosis factor (TNF)-α were increased significantly after T reg depletion in Bim -/- mice. This study demonstrates that transient depletion of T regs leads to enhanced self-reactive T effector cell function followed by exacerbation of kidney disease in the chronic spontaneous kidney disease model of Bim-deficient mice. © 2017 British Society for Immunology.

  19. Dendritic cell-mediated T cell polarization

    NARCIS (Netherlands)

    de Jong, Esther C.; Smits, Hermelijn H.; Kapsenberg, Martien L.

    2005-01-01

    Effective defense against diverse types of micro-organisms that invade our body requires specialized classes of antigen-specific immune responses initiated and maintained by distinct subsets of effector CD4(+) T helper (Th) cells. Excessive or detrimental (e.g., autoimmune) responses by effector T

  20. Cutting Edge: 2B4-Mediated Coinhibition of CD4+ T Cells Underlies Mortality in Experimental Sepsis.

    Science.gov (United States)

    Chen, Ching-Wen; Mittal, Rohit; Klingensmith, Nathan J; Burd, Eileen M; Terhorst, Cox; Martin, Greg S; Coopersmith, Craig M; Ford, Mandy L

    2017-09-15

    Sepsis is a leading cause of death in the United States, but the mechanisms underlying sepsis-induced immune dysregulation remain poorly understood. 2B4 (CD244, SLAM4) is a cosignaling molecule expressed predominantly on NK cells and memory CD8 + T cells that has been shown to regulate T cell function in models of viral infection and autoimmunity. In this article, we show that 2B4 signaling mediates sepsis lymphocyte dysfunction and mortality. 2B4 expression is increased on CD4 + T cells in septic animals and human patients at early time points. Importantly, genetic loss or pharmacologic inhibition of 2B4 significantly increased survival in a murine cecal ligation and puncture model. Further, CD4-specific conditional knockouts showed that 2B4 functions on CD4 + T cell populations in a cell-intrinsic manner and modulates adaptive and innate immune responses during sepsis. Our results illuminate a novel role for 2B4 coinhibitory signaling on CD4 + T cells in mediating immune dysregulation. Copyright © 2017 by The American Association of Immunologists, Inc.

  1. The role of CD4+ T cells in cell-mediated immunity to LCMV: studies in MHC class I and class II deficient mice

    DEFF Research Database (Denmark)

    Christensen, Jan Pravsgaard; Marker, O; Thomsen, Allan Randrup

    1994-01-01

    Parameters of the virus-specific T-cell response were analysed in order to dissect the contribution of CD4+ and CD8+ T cells to cell-mediated immunity to lymphocytic choriomeningitis virus. In MHC class II deficient mice, initial T-cell responsiveness was not impaired, but virus clearance...... was delayed, and virus-specific Td activity declined more rapidly. Furthermore, class I restricted Tc memory appeared to be impaired in these mice. To directly evaluate the role of CD4+ cells in virus clearance and T-cell mediated inflammation, MHC class I deficient mice were also studied. No virus...... exudate. This low-grade response was associated with some degree of virus control as organ titres were lower in these animals than in matched T-cell deficient nu/nu mice or class I deficient mice treated with anti-CD4 monoclonal antibody. This confirms that CD4+ cells are not needed to induce a virus...

  2. Memory CD8 T cells mediate severe immunopathology following respiratory syncytial virus infection.

    Directory of Open Access Journals (Sweden)

    Megan E Schmidt

    2018-01-01

    Full Text Available Memory CD8 T cells can provide protection from re-infection by respiratory viruses such as influenza and SARS. However, the relative contribution of memory CD8 T cells in providing protection against respiratory syncytial virus (RSV infection is currently unclear. To address this knowledge gap, we utilized a prime-boost immunization approach to induce robust memory CD8 T cell responses in the absence of RSV-specific CD4 T cells and antibodies. Unexpectedly, RSV infection of mice with pre-existing CD8 T cell memory led to exacerbated weight loss, pulmonary disease, and lethal immunopathology. The exacerbated disease in immunized mice was not epitope-dependent and occurred despite a significant reduction in RSV viral titers. In addition, the lethal immunopathology was unique to the context of an RSV infection as mice were protected from a normally lethal challenge with a recombinant influenza virus expressing an RSV epitope. Memory CD8 T cells rapidly produced IFN-γ following RSV infection resulting in elevated protein levels in the lung and periphery. Neutralization of IFN-γ in the respiratory tract reduced morbidity and prevented mortality. These results demonstrate that in contrast to other respiratory viruses, RSV-specific memory CD8 T cells can induce lethal immunopathology despite mediating enhanced viral clearance.

  3. The role of receptor-mediated T-cells activation disorders in pulmonary tuberculosis

    Directory of Open Access Journals (Sweden)

    Irina E. Esimova

    2017-01-01

    Full Text Available Aim. To analyze the peculiarities and mechanisms of receptor-mediated T-lymphocytes disorders in different clinical forms of pulmonary tuberculosis.Materials and мethods. The study involved 116 patients with first diagnosed infiltrative and disseminated drug-sensitive and drug-resistant pulmonary tuberculosis. The key stages in receptor-mediated activation of T-lymphocytes, isolated from blood, after their CD3/CD28-induction in vitro with addition of intracellular transport blocker were analyzed. Their immunotyping was carried out with the method of two- and threecolor flow cytofluorometry. The obtained results were statistically analyzed.Results. The breach of extracellular and intracellular stages of T-lymphocytes activation, shown by reduction in total number of CD3- and CD28-positive cells, and CD3+CD28+IL2+, CD3+CD28+IL2–, CD3+NF-kB+, CD3+NFAT2+ lymphocytes, and increase in number of CD3+CTLA4+ cells, was identified with most of their manifestations in disseminated drug-resistant pulmonary tuberculosis. It was shown that the content of CD3+AP-1+ lymphocytes is variable in drug-resistant pulmonary tuberculosis: it increases in the infiltrative form and decreases in the disseminated form.Conclusion. The results showed different mechanisms leading to a deficiency of IL-2-positive lymphocytes and T-lymphocytopenia: from “functional reserve” exhaustion of T-cells in drug-sensitive pulmonary tuberculosis to immunosuppression under the influence of suppressive cytokines (in case of the infiltrative form and inhibitory protein CTLA4 (in case of the disseminated form in drug-resistant pulmonary tuberculosis. 

  4. Regulatory T cells and B cells: implication on autoimmune diseases

    OpenAIRE

    Wang, Ping; Zheng, Song Guo

    2013-01-01

    The regulatory T (Treg) cells play an important role in the maintenance of homeostasis and the prevention of autoimmune diseases. Although most studies are focusing on the role of Treg cells in T cells and T cells-mediated diseases, these cells also directly affect B cells and other non-T cells. This manuscript updates the role of Treg cells on the B cells and B cell-mediated diseases. In addition, the mechanisms whereby Treg cells suppress B cell responses have been discussed.

  5. Immune responses of dendritic cells after acquiring antigen from apoptotic hepatocholangioma cells caused by γ-ray

    International Nuclear Information System (INIS)

    Wu Gang; Gu Hongguang; Han Benli; Pei Xuetao

    2002-01-01

    Objective: To investigate the induction of cytotoxic T lymphocytes (CTLs) in antitumor responsiveness and therapeutic effects after dendritic cells (DCs) acquired antigen from apoptotic hepatocholangioma cells. Methods: DCs from blood mononuclear cells that maintain the characteristics of immaturity-anti-gen-capturing and-processing capacity were established in vitro by using granulocyte/macrophage colony-stimulating factor (GM-CSF) and interleukin-4. Then, apoptosis in hepatocholangioma cells was induced with γ-radiation. The experimental groups included (1) co-culture of DCs, and apoptotic cancer cells and T cells; (2) co-culture of DCs necrotic cancer cells and T cells; (3) co-culture of DCs-cultured cancer cell and T cells. These cells were co-cultured for 7 days. DCs and T cell were enriched separately. Finally, antitumor response test was carried out. Results: These cells had typical dendritic morphology, expressed high levels of CD1a, B7 and acquired antigen from apoptotic cells caused by γ-rays and induced an increased T cell-stimulatory capacity in MLR. Conclusions: DCs obtained from blood mononuclear cells using GM-CSF and IL-4 and DCs can efficiently present antigen driven from apoptotic cells caused by γ-rays and induce T cells increasing obviously. It can probably become an effective approach of DC transduction with antigen

  6. DNA fragmentation and cell death mediated by T cell antigen receptor/CD3 complex on a leukemia T cell line.

    Science.gov (United States)

    Takahashi, S; Maecker, H T; Levy, R

    1989-10-01

    An anti-T cell receptor (TcR) monoclonal antibody (mAb), LC4, directed against a human leukemic T cell line, SUP-T13, caused DNA fragmentation ("apoptosis") and cell death upon binding to this cell line. Cross-linking of receptor molecules was necessary for this effect since F(ab')2, but not Fab', fragments of LC4 could induce cell death. Five anti-CD3 mAb tested also caused apoptosis, but only when they were presented on a solid phase. Interestingly, soluble anti-CD3 mAb induced calcium flux and had an additive effect on the calcium flux and interleukin 2 receptor expression induced by LC4, but these anti-CD3 mAb reversed the growth inhibition and apoptosis caused by LC4. The calcium ionophore A23187, but not the protein kinase C activator phorbol 12-myristate 13-acetate (PMA), also induced apoptosis, suggesting that protein kinase C activation alone does not cause apoptosis, although PMA is growth inhibitory. These results suggest that two distinct biological phenomena can accompany stimulation of the TcR/CD3 complex. In both cases, calcium flux and interleukin 2 receptor expression is induced, but only in one case is apoptosis and cell death seen. The signal initiating apoptosis can be selectively prevented by binding CD3 portion of the receptor in this cell line. This difference in signals mediated by the TcR/CD3 complex may be important in explaining the process of thymic selection, as well as in choosing anti-TcR mAb for therapeutic use.

  7. Functional dichotomy between NKG2D and CD28-mediated co-stimulation in human CD8+ T cells.

    Directory of Open Access Journals (Sweden)

    Kamalakannan Rajasekaran

    2010-09-01

    Full Text Available Both CD28 and NKG2D can function as co-stimulatory receptors in human CD8+ T cells. However, their independent functional contributions in distinct CD8+ T cell subsets are not well understood. In this study, CD8+ T cells in human peripheral blood- and lung-derived lymphocytes were analyzed for CD28 and NKG2D expression and function. We found a higher level of CD28 expression in PBMC-derived naïve (CD45RA+CD27+ and memory (CD45RA-CD27+ CD8+ T cells (CD28Hi, while its expression was significantly lower in effector (CD45RA+CD27- CD8+ T cells (CD28Lo. Irrespective of the differences in the CD28 levels, NKG2D expression was comparable in all three CD8+ T cell subsets. CD28 and NKG2D expressions followed similar patterns in human lung-resident GILGFVFTL/HLA-A2-pentamer positive CD8+ T cells. Co-stimulation of CD28Lo effector T cells via NKG2D significantly increased IFN-γ and TNF-α levels. On the contrary, irrespective of its comparable levels, NKG2D-mediated co-stimulation failed to augment IFN-γ and TNF-α production in CD28Hi naïve/memory T cells. Additionally, CD28-mediated co-stimulation was obligatory for IL-2 generation and thereby its production was limited only to the CD28Hi naïve/memory subsets. MICA, a ligand for NKG2D was abundantly expressed in the tracheal epithelial cells, validating the use of NKG2D as the major co-stimulatory receptor by tissue-resident CD8+ effector T cells. Based on these findings, we conclude that NKG2D may provide an expanded level of co-stimulation to tissue-residing effector CD8+ T cells. Thus, incorporation of co-stimulation via NKG2D in addition to CD28 is essential to activate tumor or tissue-infiltrating effector CD8+ T cells. However, boosting a recall immune response via memory CD8+ T cells or vaccination to stimulate naïve CD8+ T cells would require CD28-mediated co-stimulation.

  8. IFN-Gamma-Dependent and Independent Mechanisms of CD4⁺ Memory T Cell-Mediated Protection from Listeria Infection.

    Science.gov (United States)

    Meek, Stephanie M; Williams, Matthew A

    2018-02-13

    While CD8⁺ memory T cells can promote long-lived protection from secondary exposure to intracellular pathogens, less is known regarding the direct protective mechanisms of CD4⁺ T cells. We utilized a prime/boost model in which mice are initially exposed to an acutely infecting strain of lymphocytic choriomeningitis virus (LCMV), followed by a heterologous rechallenge with Listeria monocytogenes recombinantly expressing the MHC Class II-restricted LCMV epitope, GP 61-80 (Lm-gp61). We found that heterologous Lm-gp61 rechallenge resulted in robust activation of CD4⁺ memory T cells and that they were required for rapid bacterial clearance. We further assessed the relative roles of TNF and IFNγ in the direct anti-bacterial function of CD4⁺ memory T cells. We found that disruption of TNF resulted in a complete loss of protection mediated by CD4⁺ memory T cells, whereas disruption of IFNγ signaling to macrophages results in only a partial loss of protection. The protective effect mediated by CD4⁺ T cells corresponded to the rapid accumulation of pro-inflammatory macrophages in the spleen and an altered inflammatory environment in vivo. Overall, we conclude that protection mediated by CD4⁺ memory T cells from heterologous Listeria challenge is most directly dependent on TNF, whereas IFNγ only plays a minor role.

  9. TIM-1 glycoprotein binds the adhesion receptor P-selectin and mediates T cell trafficking during inflammation and autoimmunity

    Science.gov (United States)

    Angiari, Stefano; Donnarumma, Tiziano; Rossi, Barbara; Dusi, Silvia; Pietronigro, Enrica; Zenaro, Elena; Della Bianca, Vittorina; Toffali, Lara; Piacentino, Gennj; Budui, Simona; Rennert, Paul; Xiao, Sheng; Laudanna, Carlo; Casasnovas, Jose M.; Kuchroo, Vijay K.; Constantin, Gabriela

    2014-01-01

    SUMMARY Selectins play a central role in leukocyte trafficking by mediating tethering and rolling on vascular surfaces. Here we have reported that T cell immunoglobulin and mucin domain 1 (TIM-1) is a P-selectin ligand. We have shown that human and murine TIM-1 binds to P-selectin, and that TIM-1 mediates tethering and rolling of T helper-1 (Th1) and Th17, but not Th2 and regulatory T cells on P-selectin. Th1 and Th17 cells lacking the TIM-1 mucin domain showed reduced rolling in thrombin-activated mesenteric venules and inflamed brain microcirculation. Inhibition of TIM-1 had no effect on naive T cell homing, but reduced T cell recruitment in a skin hypersensitivity model and blocked experimental autoimmune encephalomyelitis. Uniquely, the TIM-1 IgV domain was also required for P-selectin binding. Our data demonstrate that TIM-1 is a major P-selectin ligand with a specialized role in T cell trafficking during inflammatory responses and the induction of autoimmune disease. PMID:24703780

  10. Anti-inflammatory activity of chloroquine and amodiaquine through p21-mediated suppression of T cell proliferation and Th1 cell differentiation

    International Nuclear Information System (INIS)

    Oh, Sera; Shin, Ji Hyun; Jang, Eun Jung; Won, Hee Yeon; Kim, Hyo Kyeong; Jeong, Mi- Gyeong; Kim, Kwang Soo; Hwang, Eun Sook

    2016-01-01

    Chloroquine (CQ) and amodiaquine (AQ) have been used for treating or preventing malaria for decades, and their application has expanded into treating inflammatory disease in humans. CQ and AQ are applicable for controlling rheumatoid arthritis, but their molecular mechanisms of anti-inflammatory activity remain to be elucidated. In this study, we examined the effects of CQ and AQ on T cell activation and T cell-mediated immune response. CQ had no significant effect on T cell numbers, but decreased the population of T cells with a high division rate. However, AQ treatment significantly increased the number of cells with low division rates and eliminated cells with high division rates, resulting in the inhibition of T cell proliferation triggered by T cell receptor stimulation, of which inhibition occurred in developing effector T helper and regulatory T cells, regardless of the different exogenous cytokines. Interestingly, the cyclin-dependent kinase inhibitor p21 was significantly and dose-dependently increased by CQ, and more potently by AQ, while other cell cycle regulators were unchanged. Both CQ and AQ elevated the transcription level of p21 though the activation of p53, but also blocked p21 protein degradation in the presence of cycloheximide, causing p21 protein accumulation mainly in the nucleus. Sustained treatment of developing T cells with either CQ or AQ suppressed IFN-γ production in a dose dependent manner and potently inhibited the differentiation of IFN-γ-producing Th1 cells. These results demonstrate that CQ and AQ increase the expression level of p21 and inhibit T cell proliferation and the development of IFN-γ-producing Th1 cells, thereby revealing beneficial roles in treating a wide range of chronic inflammatory diseases mediated by inflammatory T cells. -- Highlights: •T cell division rates are suppressed by chloroquine and amodiaquine treatment. •Chloroquine and amodiaquine potently increased the p21 expression. •The p21 induction is

  11. Anti-inflammatory activity of chloroquine and amodiaquine through p21-mediated suppression of T cell proliferation and Th1 cell differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Sera; Shin, Ji Hyun; Jang, Eun Jung; Won, Hee Yeon; Kim, Hyo Kyeong; Jeong, Mi- Gyeong [College of Pharmacy and Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Kim, Kwang Soo [Molecular Neurobiology Laboratory, Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA 02478 (United States); Hwang, Eun Sook, E-mail: eshwang@ewha.ac.kr [College of Pharmacy and Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 120-750 (Korea, Republic of)

    2016-05-27

    Chloroquine (CQ) and amodiaquine (AQ) have been used for treating or preventing malaria for decades, and their application has expanded into treating inflammatory disease in humans. CQ and AQ are applicable for controlling rheumatoid arthritis, but their molecular mechanisms of anti-inflammatory activity remain to be elucidated. In this study, we examined the effects of CQ and AQ on T cell activation and T cell-mediated immune response. CQ had no significant effect on T cell numbers, but decreased the population of T cells with a high division rate. However, AQ treatment significantly increased the number of cells with low division rates and eliminated cells with high division rates, resulting in the inhibition of T cell proliferation triggered by T cell receptor stimulation, of which inhibition occurred in developing effector T helper and regulatory T cells, regardless of the different exogenous cytokines. Interestingly, the cyclin-dependent kinase inhibitor p21 was significantly and dose-dependently increased by CQ, and more potently by AQ, while other cell cycle regulators were unchanged. Both CQ and AQ elevated the transcription level of p21 though the activation of p53, but also blocked p21 protein degradation in the presence of cycloheximide, causing p21 protein accumulation mainly in the nucleus. Sustained treatment of developing T cells with either CQ or AQ suppressed IFN-γ production in a dose dependent manner and potently inhibited the differentiation of IFN-γ-producing Th1 cells. These results demonstrate that CQ and AQ increase the expression level of p21 and inhibit T cell proliferation and the development of IFN-γ-producing Th1 cells, thereby revealing beneficial roles in treating a wide range of chronic inflammatory diseases mediated by inflammatory T cells. -- Highlights: •T cell division rates are suppressed by chloroquine and amodiaquine treatment. •Chloroquine and amodiaquine potently increased the p21 expression. •The p21 induction is

  12. Meningeal mast cell-T cell crosstalk regulates T cell encephalitogenicity.

    Science.gov (United States)

    Russi, Abigail E; Walker-Caulfield, Margaret E; Guo, Yong; Lucchinetti, Claudia F; Brown, Melissa A

    2016-09-01

    GM-CSF is a cytokine produced by T helper (Th) cells that plays an essential role in orchestrating neuroinflammation in experimental autoimmune encephalomyelitis, a rodent model of multiple sclerosis. Yet where and how Th cells acquire GM-CSF expression is unknown. In this study we identify mast cells in the meninges, tripartite tissues surrounding the brain and spinal cord, as important contributors to antigen-specific Th cell accumulation and GM-CSF expression. In the absence of mast cells, Th cells do not accumulate in the meninges nor produce GM-CSF. Mast cell-T cell co-culture experiments and selective mast cell reconstitution of the meninges of mast cell-deficient mice reveal that resident meningeal mast cells are an early source of caspase-1-dependent IL-1β that licenses Th cells to produce GM-CSF and become encephalitogenic. We also provide evidence of mast cell-T cell co-localization in the meninges and CNS of recently diagnosed acute MS patients indicating similar interactions may occur in human demyelinating disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Suppression of Human T Cell Proliferation Mediated by the Cathepsin B Inhibitor, z-FA-FMK Is Due to Oxidative Stress.

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    Tanuja Rajah

    Full Text Available The cathepsin B inhibitor, benzyloxycarbonyl-phenylalanine-alanine-fluoromethyl ketone (z-FA-FMK readily inhibits anti-CD3-induced human T cell proliferation, whereas the analogue benzyloxycarbonyl-phenylalanine-alanine-diazomethyl ketone (z-FA-DMK had no effect. In contrast, benzyloxycarbonyl-phenylalanine-alanine-chloromethyl ketone (z-FA-CMK was toxic. The inhibition of T cell proliferation mediated by z-FA-FMK requires not only the FMK moiety, but also the benzyloxycarbonyl group at the N-terminal, suggesting some degree of specificity in z-FA-FMK-induced inhibition of primary T cell proliferation. We showed that z-FA-FMK treatment leads to a decrease in intracellular glutathione (GSH with a concomitant increase in reactive oxygen species (ROS levels in activated T cells. The inhibition of anti-CD3-induced T cell proliferation mediated by z-FA-FMK was abolished by the presence of low molecular weight thiols such as GSH, N-acetylcysteine (NAC and L-cysteine, whereas D-cysteine which cannot be metabolised to GSH has no effect. The inhibition of anti-CD3-induced up-regulation of CD25 and CD69 expression mediated by z-FA-FMK was also attenuated in the presence of exogenous GSH. Similar to cell proliferation, GSH, NAC and L-cysteine but not D-cysteine, completely restored the processing of caspase-8 and caspase-3 to their respective subunits in z-FA-FMK-treated activated T cells. Our collective results demonstrated that the inhibition of T cell activation and proliferation mediated by z-FA-FMK is due to oxidative stress via the depletion of GSH.

  14. Protection against Mycobacterium tuberculosis infection by adoptive immunotherapy. Requirement for T cell-deficient recipients

    International Nuclear Information System (INIS)

    Orme, I.M.; Collins, F.M.

    1983-01-01

    The results of this study demonstrate that spleen cells taken from mice at the height of the primary immune response to intravenous infection with Mycobacterium tuberculosis possess the capacity to transfer adoptive protection to M. tuberculosis-infected recipients, but only if these recipients are first rendered T cell-deficient, either by thymectomy and gamma irradiation, or by sublethal irradiation. A similar requirement was necessary to demonstrate the adoptive protection of the lungs after exposure to an acute aerosol-delivered M. tuberculosis infection. In both infectious models successful adoptive immunotherapy was shown to be mediated by T lymphocytes, which were acquired in the donor animals in response to the immunizing infection. It is proposed that the results of this study may serve as a basic model for the subsequent analysis of the nature of the T cell-mediated immune response to both systemic and aerogenic infections with M. tuberculosis

  15. Aberrant TAL1 activation is mediated by an interchromosomal interaction in human T-cell acute lymphoblastic leukemia.

    Science.gov (United States)

    Patel, B; Kang, Y; Cui, K; Litt, M; Riberio, M S J; Deng, C; Salz, T; Casada, S; Fu, X; Qiu, Y; Zhao, K; Huang, S

    2014-02-01

    Long-range chromatin interactions control metazoan gene transcription. However, the involvement of intra- and interchromosomal interactions in development and oncogenesis remains unclear. TAL1/SCL is a critical transcription factor required for the development of all hematopoietic lineages; yet, aberrant TAL1 transcription often occurs in T-cell acute lymphoblastic leukemia (T-ALL). Here, we report that oncogenic TAL1 expression is regulated by different intra- and interchromosomal loops in normal hematopoietic and leukemic cells, respectively. These intra- and interchromosomal loops alter the cell-type-specific enhancers that interact with the TAL1 promoter. We show that human SET1 (hSET1)-mediated H3K4 methylations promote a long-range chromatin loop, which brings the +51 enhancer in close proximity to TAL1 promoter 1 in erythroid cells. The CCCTC-binding factor (CTCF) facilitates this long-range enhancer/promoter interaction of the TAL1 locus in erythroid cells while blocking the same enhancer/promoter interaction of the TAL1 locus in human T-cell leukemia. In human T-ALL, a T-cell-specific transcription factor c-Maf-mediated interchromosomal interaction brings the TAL1 promoter into close proximity with a T-cell-specific regulatory element located on chromosome 16, activating aberrant TAL1 oncogene expression. Thus, our study reveals a novel molecular mechanism involving changes in three-dimensional chromatin interactions that activate the TAL1 oncogene in human T-cell leukemia.

  16. CD4+ T cell-mediated rejection of MHC class II-positive tumor cells is dependent on antigen secretion and indirect presentation on host APCs.

    Science.gov (United States)

    Haabeth, Ole Audun Werner; Fauskanger, Marte; Manzke, Melanie; Lundin, Katrin U; Corthay, Alexandre; Bogen, Bjarne; Tveita, Anders Aune

    2018-05-11

    Tumor-specific CD4+ T cells have been shown to mediate efficient anti-tumor immune responses against cancer. Such responses can occur through direct binding to MHC class II (MHC II)-expressing tumor cells or indirectly via activation of professional antigen-presenting cells (APC) that take up and present the tumor antigen. We have previously shown that CD4+ T cells reactive against an epitope within the Ig light chain variable region of a murine B cell lymphoma can reject established tumors. Given the presence of MHC II molecules at the surface of lymphoma cells, we investigated whether MHC II-restricted antigen presentation on tumor cells alone was required for rejection. Variants of the A20 B lymphoma cell line that either secreted or intracellularly retained different versions of the tumor-specific antigen revealed that antigen secretion by the MHC II-expressing tumor cells was essential both for the priming and effector phase of CD4+ T cell-driven anti-tumor immune responses. Consistent with this, genetic ablation of MHC II in tumor cells, both in the case of B lymphoma and B16 melanoma, did not preclude rejection of tumors by tumor antigen-specific CD4+ T cells in vivo. These findings demonstrate that MHC class II expression on tumor cells themselves is not required for CD4+ T cell-mediated rejection, and that indirect display on host APC is sufficient for effective tumor elimination. These results support the importance of tumor-infiltrating APC as mediators of tumor cell killing by CD4+ T cells. Copyright ©2018, American Association for Cancer Research.

  17. Contribution of T cell-mediated immunity to the resistance to staphlococcal infection

    International Nuclear Information System (INIS)

    Tsuda, S.; Sasai, Y.; Minami, K.; Nomoto, K.

    1978-01-01

    Abscess formation in nude mice after subcutaneous inoculation of Staphylococcus aureus (S. aureus) was more extensive and prolonged as compared with that in phenotypically normal littermates. Abscess formation in nude mice was augmented markedly by whole-body irradiation. Not only T cell-mediated immunity but also radiosensitive, nonimmune phagocytosis appear to contribute to the resistance against staphylococcal infection

  18. Broad T-cell receptor repertoire in T-lymphocytes derived from human induced pluripotent stem cells.

    Directory of Open Access Journals (Sweden)

    Chia-Wei Chang

    Full Text Available Human induced pluripotent stem cells (hiPSCs have enormous potential for the treatment of inherited and acquired disorders. Recently, antigen-specific T lymphocytes derived from hiPSCs have been reported. However, T lymphocyte populations with broad T cell receptor (TCR diversity have not been generated. We report that hiPSCs derived from skin biopsy are capable of producing T lymphocyte populations with a broad TCR repertoire. In vitro T cell differentiation follows a similar developmental program as observed in vivo, indicated by sequential expression of CD7, intracellular CD3 and surface CD3. The γδ TCR locus is rearranged first and is followed by rearrangement of the αβ locus. Both γδ and αβ T cells display a diverse TCR repertoire. Upon activation, the cells express CD25, CD69, cytokines (TNF-α, IFN-γ, IL-2 and cytolytic proteins (Perforin and Granzyme-B. These results suggest that most, if not all, mechanisms required to generate functional T cells with a broad TCR repertoire are intact in our in vitro differentiation protocol. These data provide a foundation for production of patient-specific T cells for the treatment of acquired or inherited immune disorders and for cancer immunotherapy.

  19. Systemic immunological tolerance to ocular antigens is mediated by TNF-related apoptosis-inducing ligand (TRAIL)-expressing CD8+ T cells*

    Science.gov (United States)

    Griffith, Thomas S.; Brincks, Erik L.; Gurung, Prajwal; Kucaba, Tamara A.; Ferguson, Thomas A.

    2010-01-01

    Systemic immunological tolerance to Ag encountered in the eye restricts the formation of potentially damaging immune responses that would otherwise be initiated at other anatomical locations. We previously demonstrated that tolerance to Ag administered via the anterior chamber (AC) of the eye required FasL-mediated apoptotic death of inflammatory cells that enter the eye in response to the antigenic challenge. Moreover, the systemic tolerance induced after AC injection of Ag was mediated by CD8+ regulatory T cells. The present study examined the mechanism by which these CD8+ regulatory T cells mediate tolerance after AC injection of Ag. AC injection of Ag did not prime CD4+ T cells, and led to increased TRAIL expression by splenic CD8+ T cells. Unlike wildtype mice, Trail−/− or Dr5−/− mice did not develop tolerance to Ag injected into the eye, even though responding lymphocytes underwent apoptosis in the AC of the eyes of these mice. CD8+ T cells from Trail−/− mice that were first injected AC with Ag were unable to transfer tolerance to naïve recipient wildtype mice, but CD8+ T cells from AC-injected wildtype or Dr5−/− mice could transfer tolerance. Importantly, the transferred wildtype (Trail+/+) CD8+ T cells were also able to decrease the number of infiltrating inflammatory cells into the eye; however, Trail−/− CD8+ T cells were unable to limit the inflammatory cell ingress. Together, our data suggest that “helpless” CD8+ regulatory T cells generated after AC injection of Ag enforce systemic tolerance in a TRAIL-dependent manner to inhibit inflammation in the eye. PMID:21169546

  20. Immune-mediated bone marrow failure syndromes of progenitor and stem cells: molecular analysis of cytotoxic T cell clones.

    Directory of Open Access Journals (Sweden)

    Ramon Tiu

    2007-03-01

    Full Text Available The unique structure of the T cell receptor (TCR enables molecular identification of individual T cell clones and provides an unique opportunity for the design of molecular diagnostic tests based on the structure of the rearranged TCR chain e.g., using the TCR CDR3 region. Initially, clonal T cell malignancies, including T cell large granular lymphocyte leukemia (T-LGL, mucosis fungoides and peripheral T cell lymphoma were targets for the TCR-based analytic assays such as detection of clonality by T-gamma rearrangement using y-chain-specific PCR or Southern Blotting. Study of these disorders facilitated further analytic concepts and application of rational methods of TCR analysis to investigations of polyclonal T cell-mediated diseases. In hematology, such conditions include graft versus host disease (GvHD and immune-mediated bone marrow failure syndromes. In aplastic anemia (AA, myelodysplastic syndrome (MDS or paroxysmal nocturnal hemoglobinuria (PNH, cytotoxic T cell responses may be directed against certain antigens located on stem or more lineage-restricted progenitor cells in single lineage cytopenias. The nature of the antigenic targets driving polyclonal CTL responses remains unclear. Novel methods of TCR repertoire analysis, include VB flow cytometry, peptide-specific tetramer staining, in vitro stimulation assays and TCR CDR3-specific PCR. Such PCR assay can be either VB family-specific or multiplexed for all VB families. Amplified products can be characterized and quantitated to facilitate detection of the most immunodominant clonotypes. Such clonotypes may serve as markers for the global polyclonal T cell response. Identification of these clonotypes can be performed in blood and tissue biopsy material by various methods. Once immunodominant clonotypes corresponding to pathogenic CTL clones are identified they can serve as surrogate markers for the activity of the pathophysiologic process or even indicate the presence of specific

  1. B7h-expressing dendritic cells and plasma B cells mediate distinct outcomes of ICOS costimulation in T cell-dependent antibody responses

    Directory of Open Access Journals (Sweden)

    Larimore Kevin

    2012-06-01

    Full Text Available Abstract Background The ICOS-B7h costimulatory receptor-ligand pair is required for germinal center formation, the production of isotype-switched antibodies, and antibody affinity maturation in response to T cell-dependent antigens. However, the potentially distinct roles of regulated B7h expression on B cells and dendritic cells in T cell-dependent antibody responses have not been defined. Results We generated transgenic mice with lineage-restricted B7h expression to assess the cell-type specific roles of B7h expression on B cells and dendritic cells in regulating T cell-dependent antibody responses. Our results show that endogenous B7h expression is reduced on B cells after activation in vitro and is also reduced in vivo on antibody-secreting plasma B cells in comparison to both naïve and germinal center B cells from which they are derived. Increasing the level of B7h expression on activated and plasma B cells in B-B7hTg mice led to an increase in the number of antibody-secreting plasma cells generated after immunization and a corresponding increase in the concentration of antigen-specific high affinity serum IgG antibodies of all isotypes, without affecting the number of responding germinal center B cells. In contrast, ICOS costimulation mediated by dendritic cells in DC-B7hTg mice contributed to germinal center formation and selectively increased IgG2a production without affecting the overall magnitude of antibody responses. Conclusions Using transgenic mice with lineage-restricted B7h expression, we have revealed distinct roles of ICOS costimulation mediated by dendritic cells and B cells in the regulation of T cell-dependent antibody responses.

  2. Characterizing T Cells in SCID Patients Presenting with Reactive or Residual T Lymphocytes

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    Atar Lev

    2012-01-01

    Full Text Available Introduction. Patients with severe combined immunodeficiency (SCID may present with residual circulating T cells. While all cells are functionally deficient, resulting in high susceptibility to infections, only some of these cells are causing autoimmune symptoms. Methods. Here we compared T-cell functions including the number of circulating CD3+ T cells, in vitro responses to mitogens, T-cell receptor (TCR repertoire, TCR excision circles (TREC levels, and regulatory T cells (Tregs enumeration in several immunodeficinecy subtypes, clinically presenting with nonreactive residual cells (MHC-II deficiency or reactive cells. The latter includes patients with autoreactive clonal expanded T cell and patients with alloreactive transplacentally maternal T cells. Results. MHC-II deficient patients had slightly reduced T-cell function, normal TRECs, TCR repertoires, and normal Tregs enumeration. In contrast, patients with reactive T cells exhibited poor T-cell differentiation and activity. While the autoreactive cells displayed significantly reduced Tregs numbers, the alloreactive transplacentally acquired maternal lymphocytes had high functional Tregs. Conclusion. SCID patients presenting with circulating T cells show different patterns of T-cell activity and regulatory T cells enumeration that dictates the immunodeficient and autoimmune manifestations. We suggest that a high-tolerance capacity of the alloreactive transplacentally acquired maternal lymphocytes represents a toleration advantage, yet still associated with severe immunodeficiency.

  3. Is a Human CD8 T-Cell Vaccine Possible, and if So, What Would It Take? CD8 T-Cell Vaccines: To B or Not to B?

    Science.gov (United States)

    Beura, Lalit K; Jameson, Stephen C; Masopust, David

    2017-12-18

    Although CD8 T-cell vaccines do not have the record of success of humoral-mediated vaccines, they do not receive the same degree of effort. Many diseases, including malaria, tuberculosis, and acquired immune deficiency syndrome (AIDS) have not yielded to vaccines, and intrinsic barriers may impede approaches limited solely to generating antibodies. Moreover, population growth and modernization are driving an increased pace of new emerging global health threats (human immunodeficiency virus [HIV] is a recent example), which will create unpredictable challenges for vaccinologists. Vaccine-elicited CD8 T cells may contribute to protective modalities, although their development will require a more thorough understanding of CD8 T-cell biology, practices for manufacturing and delivering CD8 T-cell-eliciting vectors that have acceptable safety profiles, and, ultimately, the political will and faith of those that make vaccine research funding decisions. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

  4. Pulmonary stromal cells induce the generation of regulatory DC attenuating T-cell-mediated lung inflammation.

    Science.gov (United States)

    Li, Qian; Guo, Zhenhong; Xu, Xiongfei; Xia, Sheng; Cao, Xuetao

    2008-10-01

    The tissue microenvironment may affect the development and function of immune cells such as DC. Whether and how the pulmonary stromal microenvironment can affect the development and function of lung DC need to be investigated. Regulatory DC (DCreg) can regulate T-cell response. We wondered whether such regulatory DC exist in the lung and what is the effect of the pulmonary stromal microenvironment on the generation of DCreg. Here we demonstrate that murine pulmonary stromal cells can drive immature DC, which are regarded as being widely distributed in the lung, to proliferate and differentiate into a distinct subset of DCreg, which express high levels of CD11b but low levels of MHC class II (I-A), CD11c, secrete high amounts of IL-10, NO and prostaglandin E2 (PGE2) and suppress T-cell proliferation. The natural counterpart of DCreg in the lung with similar phenotype and regulatory function has been identified. Pulmonary stroma-derived TGF-beta is responsible for the differentiation of immature DC to DCreg, and DCreg-derived PGE2 contributes to their suppression of T-cell proliferation. Moreover, DCreg can induce the generation of CD4+CD25+Foxp3+ Treg. Importantly, infusion with DCreg attenuates T-cell-mediated eosinophilic airway inflammation in vivo. Therefore, the pulmonary microenvironment may drive the generation of DCreg, thus contributing to the maintenance of immune homoeostasis and the control of inflammation in the lung.

  5. The majority of lamina propria CD4(+) T-cells from scid mice with colitis undergo Fas-mediated apoptosis in vivo

    DEFF Research Database (Denmark)

    Bregenholt, S; Petersen, T R; Claesson, Mogens Helweg

    2001-01-01

    We have previously shown that adoptively transferred CD4(+) T-cells mediate an chronic colitis in severe combined immune deficient (scid) mice. Colitis is accompanied by activation and apoptosis of Fas ligand and TNF-alpha expressing CD4(+) T-cells in the diseased colonic lamina propria (Eur. J....... Immunol. 28:3655 (1998)). Here we investigate the apoptosis-inducing mechanism in these lamina propria infiltrating CD4(+) T-cells. We observe that freshly isolated lamina propria CD4(+) T-cells can kill Fas transfected P815 mastocytoma cells in a TCR/CD3 redirected chromium-release assay, but do...... not express TNF-alpha mediated cytotoxicity. Pre-incubation of the isolated lamina propria CD4(+) T-cells with an anti-FasL antiserum partially blocked killing of the Fas transfected target cells, indicating a role for the Fas-FasL system in the killing process. Treatment of scid mice with colitis with anti-Fas...

  6. NLRP10 Enhances CD4+ T-Cell-Mediated IFNγ Response via Regulation of Dendritic Cell-Derived IL-12 Release

    Directory of Open Access Journals (Sweden)

    Maurizio Vacca

    2017-11-01

    Full Text Available NLRP10 is a nucleotide-binding oligomerization domain-like receptor that functions as an intracellular pattern recognition receptor for microbial products. Here, we generated a Nlrp10−/− mouse to delineate the role of NLRP10 in the host immune response and found that Nlrp10−/− dendritic cells (DCs elicited sub-optimal IFNγ production by antigen-specific CD4+ T cells compared to wild-type (WT DCs. In response to T-cell encounter, CD40 ligation or Toll-like receptor 9 stimulation, Nlrp10−/− DCs produced low levels of IL-12, due to a substantial decrease in NF-κB activation. Defective IL-12 production was also evident in vivo and affected IFNγ production by CD4+ T cells. Upon Mycobacterium tuberculosis (Mtb infection, Nlrp10−/− mice displayed diminished T helper 1-cell responses and increased bacterial growth compared to WT mice. These data indicate that NLRP10-mediated IL-12 production by DCs is critical for IFNγ induction in T cells and contributes to promote the host defense against Mtb.

  7. Scaffold protein JLP mediates TCR-initiated CD4+T cell activation and CD154 expression.

    Science.gov (United States)

    Yan, Qi; Yang, Cheng; Fu, Qiang; Chen, Zhaowei; Liu, Shan; Fu, Dou; Rahman, Rahmat N; Nakazato, Ryota; Yoshioka, Katsuji; Kung, Sam K P; Ding, Guohua; Wang, Huiming

    2017-07-01

    CD4 + T-cell activation and its subsequent induction of CD154 (CD40 ligand, CD40L) expression are pivotal in shaping both the humoral and cellular immune responses. Scaffold protein JLP regulates signal transduction pathways and molecular trafficking inside cells, thus represents a critical component in maintaining cellular functions. Its role in regulating CD4 + T-cell activation and CD154 expression, however, is unclear. Here, we demonstrated expression of JLP in mouse tissues of lymph nodes, thymus, spleen, and also CD4 + T cells. Using CD4+ T cells from jlp-deficient and jlp-wild-type mice, we demonstrated that JLP-deficiency impaired T-cell proliferation, IL-2 production, and CD154 induction upon TCR stimulations, but had no impacts on the expression of other surface molecules such as CD25, CD69, and TCR. These observed impaired T-cell functions in the jlp-/- CD4 + T cells were associated with defective NF-AT activation and Ca 2 + influx, but not the MAPK, NF-κB, as well as AP-1 signaling pathways. Our findings indicated that, for the first time, JLP plays a critical role in regulating CD4 + T cells response to TCR stimulation partly by mediating the activation of TCR-initiated Ca 2+ /NF-AT. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. ArtinM Mediates Murine T Cell Activation and Induces Cell Death in Jurkat Human Leukemic T Cells

    Science.gov (United States)

    Oliveira-Brito, Patrícia Kellen Martins; Gonçalves, Thiago Eleutério; Vendruscolo, Patrícia Edivânia; Roque-Barreira, Maria Cristina

    2017-01-01

    The recognition of cell surface glycans by lectins may be critical for the innate and adaptive immune responses. ArtinM, a d-mannose-binding lectin from Artocarpus heterophyllus, activates antigen-presenting cells by recognizing TLR2 N-glycans and induces Th1 immunity. We recently demonstrated that ArtinM stimulated CD4+ T cells to produce proinflammatory cytokines. Here, we further studied the effects of ArtinM on adaptive immune cells. We showed that ArtinM activates murine CD4+ and CD8+ T cells, augmenting their positivity for CD25, CD69, and CD95 and showed higher interleukin (IL)-2 and interferon (IFN)-γ production. The CD4+ T cells exhibited increased T-bet expression in response to ArtinM, and IL-2 production by CD4+ and CD8+ T cells depended on the recognition of CD3εγ-chain glycans by ArtinM. The ArtinM effect on aberrantly-glycosylated neoplastic lymphocytes was studied in Jurkat T cells, in which ArtinM induced IL-2, IFN-γ, and IL-1β production, but decreased cell viability and growth. A higher frequency of AnnexinV- and propidium iodide-stained cells demonstrated the induction of Jurkat T cells apoptosis by ArtinM, and this apoptotic response was reduced by caspases and protein tyrosine kinase inhibitors. The ArtinM effects on murine T cells corroborated with the immunomodulatory property of lectin, whereas the promotion of Jurkat T cells apoptosis may reflect a potential applicability of ArtinM in novel strategies for treating lymphocytic leukemia. PMID:28665310

  9. A retinoic acid-dependent checkpoint in the development of CD4+ T cell-mediated immunity.

    Science.gov (United States)

    Pino-Lagos, Karina; Guo, Yanxia; Brown, Chrysothemis; Alexander, Matthew P; Elgueta, Raúl; Bennett, Kathryn A; De Vries, Victor; Nowak, Elizabeth; Blomhoff, Rune; Sockanathan, Shanthini; Chandraratna, Roshantha A; Dmitrovsky, Ethan; Noelle, Randolph J

    2011-08-29

    It is known that vitamin A and its metabolite, retinoic acid (RA), are essential for host defense. However, the mechanisms for how RA controls inflammation are incompletely understood. The findings presented in this study show that RA signaling occurs concurrent with the development of inflammation. In models of vaccination and allogeneic graft rejection, whole body imaging reveals that RA signaling is temporally and spatially restricted to the site of inflammation. Conditional ablation of RA signaling in T cells significantly interferes with CD4(+) T cell effector function, migration, and polarity. These findings provide a new perspective of the role of RA as a mediator directly controlling CD4(+) T cell differentiation and immunity. © 2011 Pino-Lagos et al.

  10. β-Arrestin-2-Dependent Signaling Promotes CCR4-mediated Chemotaxis of Murine T-Helper Type 2 Cells.

    Science.gov (United States)

    Lin, Rui; Choi, Yeon Ho; Zidar, David A; Walker, Julia K L

    2018-06-01

    Allergic asthma is a complex inflammatory disease that leads to significant healthcare costs and reduction in quality of life. Although many cell types are implicated in the pathogenesis of asthma, CD4 + T-helper cell type 2 (Th2) cells are centrally involved. We previously reported that the asthma phenotype is virtually absent in ovalbumin-sensitized and -challenged mice that lack global expression of β-arrestin (β-arr)-2 and that CD4 + T cells from these mice displayed significantly reduced CCL22-mediated chemotaxis. Because CCL22-mediated activation of CCR4 plays a role in Th2 cell regulation in asthmatic inflammation, we hypothesized that CCR4-mediated migration of CD4 + Th2 cells to the lung in asthma may use β-arr-dependent signaling. To test this hypothesis, we assessed the effect of various signaling inhibitors on CCL22-induced chemotaxis using in vitro-polarized primary CD4 + Th2 cells from β-arr2-knockout and wild-type mice. Our results show, for the first time, that CCL22-induced, CCR4-mediated Th2 cell chemotaxis is dependent, in part, on a β-arr2-dependent signaling pathway. In addition, we show that this chemotactic signaling mechanism involves activation of P-p38 and Rho-associated protein kinase. These findings point to a proinflammatory role for β-arr2-dependent signaling and support β-arr2 as a novel therapeutic target in asthma.

  11. LKB1 mediates the development of conventional and innate T cells via AMP-dependent kinase autonomous pathways.

    Directory of Open Access Journals (Sweden)

    Marouan Zarrouk

    Full Text Available The present study has examined the role of the serine/threonine kinase LKB1 in the survival and differentiation of CD4/8 double positive thymocytes. LKB1-null DPs can respond to signals from the mature α/β T-cell-antigen receptor and initiate positive selection. However, in the absence of LKB1, thymocytes fail to mature to conventional single positive cells causing severe lymphopenia in the peripheral lymphoid tissues. LKB1 thus appears to be dispensable for positive selection but important for the maturation of positively selected thymocytes. LKB1 also strikingly prevented the development of invariant Vα14 NKT cells and innate TCR αβ gut lymphocytes. Previous studies with gain of function mutants have suggested that the role of LKB1 in T cell development is mediated by its substrate the AMP-activated protein kinase (AMPK. The present study now analyses the impact of AMPK deletion in DP thymocytes and shows that the role of LKB1 during the development of both conventional and innate T cells is mediated by AMPK-independent pathways.

  12. Anti-allergic activity of 2,4,6-trihydroxy-3-geranylacetophenone (tHGA) via attenuation of IgE-mediated mast cell activation and inhibition of passive systemic anaphylaxis

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Ji Wei; Israf, Daud Ahmad; Harith, Hanis Hazeera; Md Hashim, Nur Fariesha [Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400 (Malaysia); Ng, Chean Hui; Shaari, Khozirah [Faculty of Science, Universiti Putra Malaysia, Serdang 43300 (Malaysia); Tham, Chau Ling, E-mail: chauling@upm.edu.my [Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400 (Malaysia)

    2017-03-15

    tHGA, a geranyl acetophenone compound originally isolated from a local shrub called Melicope ptelefolia, has been previously reported to prevent ovalbumin-induced allergic airway inflammation in a murine model of allergic asthma by targeting cysteinyl leukotriene synthesis. Mast cells are immune effector cells involved in the pathogenesis of allergic diseases including asthma by releasing cysteinyl leukotrienes. The anti-asthmatic properties of tHGA could be attributed to its inhibitory effect on mast cell degranulation. As mast cell degranulation is an important event in allergic responses, this study aimed to investigate the anti-allergic effects of tHGA in cellular and animal models of IgE-mediated mast cell degranulation. For in vitro model of IgE-mediated mast cell degranulation, DNP-IgE-sensitized RBL-2H3 cells were pre-treated with tHGA before challenged with DNP-BSA to induce degranulation. For IgE-mediated passive systemic anaphylaxis, Sprague Dawley rats were sensitized by intraperitoneal injection of DNP-IgE before challenged with DNP-BSA. Both in vitro and in vivo models showed that tHGA significantly inhibited the release of preformed mediators (β-hexosaminidase and histamine) as well as de novo mediators (interleukin-4, tumour necrosis factor-α, prostaglandin D{sub 2} and leukotriene C{sub 4}). Pre-treatment of tHGA also prevented IgE-challenged RBL-2H3 cells and peritoneal mast cells from undergoing morphological changes associated with mast cell degranulation. These findings indicate that tHGA possesses potent anti-allergic activity via attenuation of IgE-mediated mast cell degranulation and inhibition of IgE-mediated passive systemic anaphylaxis. Thus, tHGA may have the potential to be developed as a mast cell stabilizer for the treatment of allergic diseases in the future. - Highlights: • The in vitro and in vivo mast cell stabilizing effects of tHGA were examined. • tHGA counteracts the plasma membrane deformation in degranulating mast

  13. Anti-allergic activity of 2,4,6-trihydroxy-3-geranylacetophenone (tHGA) via attenuation of IgE-mediated mast cell activation and inhibition of passive systemic anaphylaxis

    International Nuclear Information System (INIS)

    Tan, Ji Wei; Israf, Daud Ahmad; Harith, Hanis Hazeera; Md Hashim, Nur Fariesha; Ng, Chean Hui; Shaari, Khozirah; Tham, Chau Ling

    2017-01-01

    tHGA, a geranyl acetophenone compound originally isolated from a local shrub called Melicope ptelefolia, has been previously reported to prevent ovalbumin-induced allergic airway inflammation in a murine model of allergic asthma by targeting cysteinyl leukotriene synthesis. Mast cells are immune effector cells involved in the pathogenesis of allergic diseases including asthma by releasing cysteinyl leukotrienes. The anti-asthmatic properties of tHGA could be attributed to its inhibitory effect on mast cell degranulation. As mast cell degranulation is an important event in allergic responses, this study aimed to investigate the anti-allergic effects of tHGA in cellular and animal models of IgE-mediated mast cell degranulation. For in vitro model of IgE-mediated mast cell degranulation, DNP-IgE-sensitized RBL-2H3 cells were pre-treated with tHGA before challenged with DNP-BSA to induce degranulation. For IgE-mediated passive systemic anaphylaxis, Sprague Dawley rats were sensitized by intraperitoneal injection of DNP-IgE before challenged with DNP-BSA. Both in vitro and in vivo models showed that tHGA significantly inhibited the release of preformed mediators (β-hexosaminidase and histamine) as well as de novo mediators (interleukin-4, tumour necrosis factor-α, prostaglandin D 2 and leukotriene C 4 ). Pre-treatment of tHGA also prevented IgE-challenged RBL-2H3 cells and peritoneal mast cells from undergoing morphological changes associated with mast cell degranulation. These findings indicate that tHGA possesses potent anti-allergic activity via attenuation of IgE-mediated mast cell degranulation and inhibition of IgE-mediated passive systemic anaphylaxis. Thus, tHGA may have the potential to be developed as a mast cell stabilizer for the treatment of allergic diseases in the future. - Highlights: • The in vitro and in vivo mast cell stabilizing effects of tHGA were examined. • tHGA counteracts the plasma membrane deformation in degranulating mast cells. • t

  14. Exposure to apoptotic activated CD4+ T cells induces maturation and APOBEC3G-mediated inhibition of HIV-1 infection in dendritic cells.

    Directory of Open Access Journals (Sweden)

    Venkatramanan Mohanram

    Full Text Available Dendritic cells (DCs are activated by signaling via pathogen-specific receptors or exposure to inflammatory mediators. Here we show that co-culturing DCs with apoptotic HIV-infected activated CD4(+ T cells (ApoInf or apoptotic uninfected activated CD4(+ T cells (ApoAct induced expression of co-stimulatory molecules and cytokine release. In addition, we measured a reduced HIV infection rate in DCs after co-culture with ApoAct. A prerequisite for reduced HIV infection in DCs was activation of CD4(+ T cells before apoptosis induction. DCs exposed to ApoAct or ApoInf secreted MIP-1α, MIP-1β, MCP-1, and TNF-α; this effect was retained in the presence of exogenous HIV. The ApoAct-mediated induction of co-stimulatory CD86 molecules and reduction of HIV infection in DCs were partially abrogated after blocking TNF-α using monoclonal antibodies. APOBEC3G expression in DCs was increased in co-cultures of DCs and ApoAct but not by apoptotic resting CD4(+ T cells (ApoRest. Silencing of APOBEC3G in DC abrogated the HIV inhibitory effect mediated by ApoAct. Sequence analyses of an env region revealed significant induction of G-to-A hypermutations in the context of GG or GA dinucleotides in DNA isolated from DCs exposed to HIV and ApoAct. Thus, ApoAct-mediated DC maturation resulted in induction of APOBEC3G that was important for inhibition of HIV-infection in DCs. These findings underscore the complexity of differential DC responses evoked upon interaction with resting as compared with activated dying cells during HIV infection.

  15. Revisiting the phenotypic and genetic profiling of anergic T cells mediating long-term transplant tolerance.

    Science.gov (United States)

    You, Sylvaine; Chatenoud, Lucienne

    2018-02-01

    Herein our focus will be to revisit peripheral tolerance mechanisms and in particular 'active' or 'dominant' tolerance as originally defined and mediated by regulatory CD4FoxP3 T lymphocytes (Treg) and also T-cell anergy that appears as a major mainstay to support long-term allograft survival. It is at the same time interesting and rewarding that the tool that recently guided our efforts along this path is the in-vivo use of CD3 antibody, the first monoclonal introduced in the clinic (Orthoclone OKT3) about 35 years ago to treat and prevent rejection of renal allografts. Beyond their immunosuppressive activity, whenever administered judiciously, CD3 antibodies promote robust allograft tolerance through selective purging of alloreactive effectors, resetting Treg-mediated active tolerance and promoting a unique subset of anergic CD8 T cells. The new findings discussed open up new perspectives from both a fundamental and a clinical point of view. In basic research, concrete molecular signaling paths are now spotted to finely dissect the conditions that lead to the establishment and maintenance of robust T-lymphocyte anergy mediating allograft tolerance. In the clinic, this may rapidly translate into novel biomarkers to be used in parallel to the ones already available, to better adapt posttransplant immunotherapy and monitor for long-term allograft acceptance.

  16. T-cell epitopes from viral and tumor associated antigens: induction and analysis of antigen-specific T cells

    OpenAIRE

    Nastke, Maria-Dorothea

    2005-01-01

    T cells are important effectors in the defense of human pathogens entering the organism. CD8+ T cells recognize peptides which are presented by MHC class I molecules and lyse cells which are infected by virus or intracellular pathogens. Moreover, they are able to destroy cancer cells. CD4+ T cells recognize peptides from exogenous proteins acquired by endocytosis or from internalized plasma membrane proteins which are presented on MHC class II. CD4+ T cells play an important role in the defen...

  17. Dopamine Receptor D3 Signaling on CD4+ T Cells Favors Th1- and Th17-Mediated Immunity.

    Science.gov (United States)

    Contreras, Francisco; Prado, Carolina; González, Hugo; Franz, Dafne; Osorio-Barrios, Francisco; Osorio, Fabiola; Ugalde, Valentina; Lopez, Ernesto; Elgueta, Daniela; Figueroa, Alicia; Lladser, Alvaro; Pacheco, Rodrigo

    2016-05-15

    Dopamine receptor D3 (DRD3) expressed on CD4(+) T cells is required to promote neuroinflammation in a murine model of Parkinson's disease. However, how DRD3 signaling affects T cell-mediated immunity remains unknown. In this study, we report that TCR stimulation on mouse CD4(+) T cells induces DRD3 expression, regardless of the lineage specification. Importantly, functional analyses performed in vivo using adoptive transfer of OVA-specific OT-II cells into wild-type recipients show that DRD3 deficiency in CD4(+) T cells results in attenuated differentiation of naive CD4(+) T cells toward the Th1 phenotype, exacerbated generation of Th2 cells, and unaltered Th17 differentiation. The reciprocal regulatory effect of DRD3 signaling in CD4(+) T cells favoring Th1 generation and impairing the acquisition of Th2 phenotype was also reproduced using in vitro approaches. Mechanistic analysis indicates that DRD3 signaling evokes suppressor of cytokine signaling 5 expression, a negative regulator of Th2 development, which indirectly favors acquisition of Th1 phenotype. Accordingly, DRD3 deficiency results in exacerbated eosinophil infiltration into the airways of mice undergoing house dust mite-induced allergic response. Interestingly, our results show that, upon chronic inflammatory colitis induced by transfer of naive CD4(+) T cells into lymphopenic recipients, DRD3 deficiency not only affects Th1 response, but also the frequency of Th17 cells, suggesting that DRD3 signaling also contributes to Th17 expansion under chronic inflammatory conditions. In conclusion, our findings indicate that DRD3-mediated signaling in CD4(+) T cells plays a crucial role in the balance of effector lineages, favoring the inflammatory potential of CD4(+) T cells. Copyright © 2016 by The American Association of Immunologists, Inc.

  18. Mixed Signals: Co-Stimulation in Invariant Natural Killer T Cell-Mediated Cancer Immunotherapy

    Directory of Open Access Journals (Sweden)

    Susannah C. Shissler

    2017-11-01

    Full Text Available Invariant natural killer T (iNKT cells are an integral component of the immune system and play an important role in antitumor immunity. Upon activation, iNKT cells can directly kill malignant cells as well as rapidly produce cytokines that stimulate other immune cells, making them a front line defense against tumorigenesis. Unfortunately, iNKT cell number and activity are reduced in multiple cancer types. This anergy is often associated with upregulation of co-inhibitory markers such as programmed death-1. Similar to conventional T cells, iNKT cells are influenced by the conditions of their activation. Conventional T cells receive signals through the following three types of receptors: (1 T cell receptor (TCR, (2 co-stimulation molecules, and (3 cytokine receptors. Unlike conventional T cells, which recognize peptide antigen presented by MHC class I or II, the TCRs of iNKT cells recognize lipid antigen in the context of the antigen presentation molecule CD1d (Signal 1. Co-stimulatory molecules can positively and negatively influence iNKT cell activation and function and skew the immune response (Signal 2. This study will review the background of iNKT cells and their co-stimulatory requirements for general function and in antitumor immunity. We will explore the impact of monoclonal antibody administration for both blocking inhibitory pathways and engaging stimulatory pathways on iNKT cell-mediated antitumor immunity. This review will highlight the incorporation of co-stimulatory molecules in antitumor dendritic cell vaccine strategies. The use of co-stimulatory intracellular signaling domains in chimeric antigen receptor-iNKT therapy will be assessed. Finally, we will explore the influence of innate-like receptors and modification of immunosuppressive cytokines (Signal 3 on cancer immunotherapy.

  19. T Cell-Mediated Immunity towards Yellow Fever Virus and Useful Animal Models.

    Science.gov (United States)

    Watson, Alan M; Klimstra, William B

    2017-04-11

    The 17D line of yellow fever virus vaccines is among the most effective vaccines ever created. The humoral and cellular immunity elicited by 17D has been well characterized in humans. Neutralizing antibodies have long been known to provide protection against challenge with a wild-type virus. However, a well characterized T cell immune response that is robust, long-lived and polyfunctional is also elicited by 17D. It remains unclear whether this arm of immunity is protective following challenge with a wild-type virus. Here we introduce the 17D line of yellow fever virus vaccines, describe the current state of knowledge regarding the immunity directed towards the vaccines in humans and conclude with a discussion of animal models that are useful for evaluating T cell-mediated immune protection to yellow fever virus.

  20. Measuring T cell-mediated cytotoxicity using fluorogenic caspase substrates.

    Science.gov (United States)

    Chahroudi, A; Silvestri, G; Feinberg, M B

    2003-10-01

    Cytotoxic T lymphocytes (CTLs) play a major role in the immune response against viruses and other intracellular pathogens. In addition, CTLs are implicated in the control of tumor cells in certain settings. Accurate measures of CTL function are of critical importance to study the pathogenesis of infectious diseases and to evaluate the efficacy of new vaccines and immunotherapies. To this end, we have recently developed a flow cytometry-based CTL (FCC) assay that measures the CTL-induced caspase activation within target cells using cell permeable fluorogenic caspase substrates. This novel assay reliably detects, by flow cytometry or fluorescence/confocal microscopy, antigen-specific CTLs in a wide variety of human and murine systems, and is safer and more informative than the standard 51Cr-release assay. In addition, the flow cytometric CTL (FCC) assay provides an alternative method that is often more sensitive and physiologically informative when compared to previously described FCC assays, as it measures a biological indicator of apoptosis within the target cell. The FCC assay may thus represent a useful tool to further understand the molecular and cellular mechanisms that underlie CTL-mediated killing during tumorigenesis or following infection with viruses or other intracellular pathogens.

  1. Malaria drives T cells to exhaustion

    Directory of Open Access Journals (Sweden)

    Michelle N Wykes

    2014-05-01

    Full Text Available Malaria is a significant global burden but after >30 years of effort there is no vaccine on the market. While the complex life cycle of the parasite presents several challenges, many years of research have also identified several mechanisms of immune evasion by Plasmodium spp.. Recent research on malaria, has investigated the Programmed cell death-1 (PD-1 pathway which mediates exhaustion of T cells, characterized by poor effector functions and recall responses and in some cases loss of the cells by apoptosis. Such studies have shown exhaustion of CD4+ T cells and an unappreciated role for CD8+ T cells in promoting sterile immunity against blood stage malaria. This is because PD-1 mediates up to a 95% reduction in numbers and functional capacity of parasite-specific CD8+ T cells, thus masking their role in protection. The role of T cell exhaustion during malaria provides an explanation for the absence of sterile immunity following the clearance of acute disease which will be relevant to future malaria-vaccine design and suggests the need for novel therapeutic solutions. This review will thus examine the role of PD-1-mediated T cell exhaustion in preventing lasting immunity against malaria.

  2. Coxsackievirus-mediated hyperglycemia is enhanced by reinfection and this occurs independent of T cells

    International Nuclear Information System (INIS)

    Horwitz, Marc S.; Ilic, Alex; Fine, Cody; Rodriguez, Enrique; Sarvetnick, Nora

    2003-01-01

    The induction of autoimmunity by viruses has been hypothesized to occur by a number of mechanisms. Coxsackievirus B4 (CB4) induces hyperglycemia in SJL mice resembling diabetes in humans. While virus is effectively cleared within 2 weeks, hyperglycemia does not appear until about 8-12 weeks postinfection at a time when replicative virus is no longer detectable. In SJL mice, reinfection with CB4 enhanced the development of hyperglycemia. As predicted, the immune system responded more rapidly to the second infection and virus was cleared more swiftly. However, while infiltrating T cells were found within the pancreas, depletion of the CD4 T cell population prior to secondary infection or use of CD8 knock-out mice had no effect on the development of virus-mediated hyperglycemia. In conclusion, enhanced hyperglycemia induced by CB4 occurs independent of the T cell response

  3. Regulation of DC development and DC-mediated T-cell immunity via CISH

    OpenAIRE

    Miah, Mohammad Alam; Bae, Yong-Soo

    2013-01-01

    Cytokine inducible SH2-containing protein (CISH) plays a crucial role in type 1 dendritic cell (DC) development as well as in the DC-mediated activation of cytotoxic T lymphocytes (CTLs). CISH expression at late DC developmental stages shuts down the proliferation of DC progenitors by negatively regulating signal transducer and activator of transcription 5 (STAT5) and facilitates the differentiation of DCs into potent stimulators of CTLs.

  4. Regulation of DC development and DC-mediated T-cell immunity via CISH.

    Science.gov (United States)

    Miah, Mohammad Alam; Bae, Yong-Soo

    2013-03-01

    Cytokine inducible SH2-containing protein (CISH) plays a crucial role in type 1 dendritic cell (DC) development as well as in the DC-mediated activation of cytotoxic T lymphocytes (CTLs). CISH expression at late DC developmental stages shuts down the proliferation of DC progenitors by negatively regulating signal transducer and activator of transcription 5 (STAT5) and facilitates the differentiation of DCs into potent stimulators of CTLs.

  5. Feline glycoprotein A repetitions predominant anchors transforming growth factor beta on the surface of activated CD4(+)CD25(+) regulatory T cells and mediates AIDS lentivirus-induced T cell immunodeficiency.

    Science.gov (United States)

    Miller, Michelle M; Fogle, Jonathan E; Ross, Peter; Tompkins, Mary B

    2013-04-01

    Using the feline immunodeficiency virus (FIV) model for AIDS-lentivirus infection, our laboratory has previously demonstrated that T regulatory (Treg) cell-mediated immune T and B cell dysfunction contributes to lentivirus persistence and chronic disease through membrane bound transforming growth factor beta (mTGFb). Studying Treg cells in the context of infection has been problematic as no inducible marker for activated Treg cells had been identified. However, recent reports in human Treg studies have described a novel protein, glycoprotein A repetitions predominant (GARP), as a unique marker of activated human Treg cells that anchors mTGFb. Herein we extend these studies to the feline Treg system, identifying feline GARP and demonstrating that human and feline GARP proteins are homologous in structure, expression pattern, and ability to form a complex with TGFb. We further demonstrate that GARP and TGFb form a complex on the surface of activated Treg cells and that these GARP(+)TGFb(+) Treg cells are highly efficient suppressor cells. Analysis of expression of this Treg activation marker in the FIV-AIDS model reveals an up-regulation of GARP expressing Treg cells during chronic FIV infection. We demonstrate that the GARP(+) Treg cells from FIV-infected cats suppress T helper cells in vivo and that blocking GARP or TGFb eliminates this suppression. These data suggest that GARP is expressed in complex with TGFb on the surface of activated Treg cells and plays an important role in TGFb(+) Treg-mediated T cell immune suppression during lentivirus infection.

  6. CD4+ T Cells Mediate Aspergillosis Vaccine Protection.

    Science.gov (United States)

    Diaz-Arevalo, Diana; Kalkum, Markus

    2017-01-01

    Adaptive effector CD4 + T cells play essential roles in the defense against fungal infections, especially against invasive aspergillosis (IA). Such protective CD4 + T cells can be generated through immunization with specialized antifungal vaccines, as has been demonstrated for pulmonary Aspergillus fumigatus infections in mouse experiments. Adaptive transfer of fungal antigen-specific CD4 + T cells conferred protection onto non-immunized naive mice, an experimental approach that could potentially become a future treatment option for immunosuppressed IA patients, focusing on the ultimate goal to improve their otherwise dim chances for survival. Here, we describe the different techniques to analyze CD4 + T cell immune responses after immunization with a recombinant fungal protein. We present three major methods that are used to analyze the role of CD4 + T cells in protection against A. fumigatus challenge. They include (1) transplantation of CD4 + T cells from vaccinated mice into immunosuppressed naive mice, observing increasing protection of the cell recipients, (2) depletion of CD4 + T cells from vaccinated mice, which abolishes vaccine protection, and (3) T cell proliferation studies following stimulation with overlapping synthetic peptides or an intact protein vaccine. The latter can be used to validate immunization status and to identify protective T cell epitopes in vaccine antigens. In the methods detailed here, we used versions of the well-studied Asp f3 protein expressed in a bacterial host, either as the intact full length protein or its N-terminally truncated version, comprised of residues 15-168. However, these methods are generally applicable and can well be adapted to study other protein-based subunit vaccines.

  7. Mathematical modeling on T-cell mediated adaptive immunity in primary dengue infections.

    Science.gov (United States)

    Sasmal, Sourav Kumar; Dong, Yueping; Takeuchi, Yasuhiro

    2017-09-21

    At present, dengue is the most common mosquito-borne viral disease in the world, and the global dengue incidence is increasing day by day due to climate changing. Here, we present a mathematical model of dengue viruses (DENVs) dynamics in micro-environment (cellular level) consisting of healthy cells, infected cells, virus particles and T-cell mediated adaptive immunity. We have considered the explicit role of cytokines and antibody in our model. We find that the virus load goes down to zero within 6 days as it is common for DENV infection. From our analysis, we have identified the important model parameters and done the numerical simulation with respect to such important parameters. We have shown that the cytokine mediated virus clearance plays a very important role in dengue dynamics. It can change the dynamical behavior of the system and causes essential extinction of the virus. Finally, we have incorporated the antiviral treatment for dengue in our model and shown that the basic reproduction number is directly proportional to the antiviral treatment effects. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Opposing effects of CXCR3 and CCR5 deficiency on CD8+ T cell-mediated inflammation in the central nervous system of virus-infected mice

    DEFF Research Database (Denmark)

    de Lemos, Carina; Christensen, Jeanette Erbo; Nansen, Anneline

    2005-01-01

    and therefore protect mice against the otherwise fatal CD8+ T cell-mediated immune attack. Contrary to expectations, the accumulation of mononuclear cells in cerebrospinal fluid was only slightly delayed compared with mice with normal expression of both receptors. Even more surprising, CXCR3/CCR5 double-deficient......T cells play a key role in the control of viral infection in the CNS but may also contribute to immune-mediated cell damage. To study the redundancy of the chemokine receptors CXCR3 and CCR5 in regulating virus-induced CD8+ T cell-mediated inflammation in the brain, CXCR3/CCR5 double-deficient mice...... mice were more susceptible to intracerebral infection than CXCR3-deficient mice. Analysis of effector T cell generation revealed an accelerated antiviral CD8+ T cell response in CXCR3/CCR5 double-deficient mice. Furthermore, while the accumulation of CD8+ T cells in the neural parenchyma...

  9. Nonmalignant T cells stimulate growth of T-cell lymphoma cells in the presence of bacterial toxins

    DEFF Research Database (Denmark)

    Woetmann, Anders; Lovato, Paola; Eriksen, Karsten W

    2007-01-01

    Bacterial toxins including staphylococcal enterotoxins (SEs) have been implicated in the pathogenesis of cutaneous T-cell lymphomas (CTCLs). Here, we investigate SE-mediated interactions between nonmalignant T cells and malignant T-cell lines established from skin and blood of CTCL patients....... The malignant CTCL cells express MHC class II molecules that are high-affinity receptors for SE. Although treatment with SE has no direct effect on the growth of the malignant CTCL cells, the SE-treated CTCL cells induce vigorous proliferation of the SE-responsive nonmalignant T cells. In turn, the nonmalignant...... T cells enhance proliferation of the malignant cells in an SE- and MHC class II-dependent manner. Furthermore, SE and, in addition, alloantigen presentation by malignant CTCL cells to irradiated nonmalignant CD4(+) T-cell lines also enhance proliferation of the malignant cells. The growth...

  10. Memory CD8+ T Cells: Orchestrators and Key Players of Innate Immunity?

    Directory of Open Access Journals (Sweden)

    Grégoire Lauvau

    2016-09-01

    Full Text Available Over the past decades, the dichotomy between innate and adaptive immune responses has largely dominated our understanding of immunology. Upon primary encounter with microbial pathogens, differentiation of adaptive immune cells into functional effectors usually takes several days or even longer, making them contribute to host protection only late during primary infection. However, once generated, antigen-experienced T lymphocytes can persist in the organism and constitute a pool of memory cells that mediate fast and effective protection to a recall infection with the same microbial pathogen. Herein, we challenge this classical paradigm by highlighting the "innate nature" of memory CD8+ T cells. First, within the thymus or in the periphery, naïve CD8+ T cells may acquire phenotypic and functional characteristics of memory CD8+ T cells independently of challenge with foreign antigens. Second, both the "unconventional" and the "conventional" memory cells can rapidly express protective effector functions in response to sets of inflammatory cytokines and chemokines signals, independent of cognate antigen triggering. Third, memory CD8+ T cells can act by orchestrating the recruitment, activation, and licensing of innate cells, leading to broad antimicrobial states. Thus, collectively, memory CD8+ T cells may represent important actors of innate immune defenses.

  11. T-cell mediated immunity in Wegener's granulomatosis

    NARCIS (Netherlands)

    Abdulahad, Wayel Habib

    2008-01-01

    Although the pathogenetic mechanisms involved in Wegener’s granulomatosis (WG) are not completely understood, considerable evidence support the concepts that activated T-cells play an important role in disease expression. It is, however, not clear which subsets of T-cells are involved in the

  12. Immune-mediated neuropathy with Epstein-Barr virus-positive T-cell lymphoproliferative disease.

    Science.gov (United States)

    Hattori, Takaaki; Arai, Ayako; Yokota, Takanori; Imadome, Ken-Ichi; Tomimitsu, Hiroyuki; Miura, Osamu; Mizusawa, Hidehiro

    2015-01-01

    A 47-year-old man with Epstein-Barr virus (EBV)-positive T/NK- cell lymphoproliferative disease (EBV-T/NK-LPD) developed acute-onset weakness. A nerve conduction study showed a conduction block in both the proximal and most distal segments. Although the patient's neuropathy transiently responded to intravenous immunoglobulin, it was progressive for at least 25 days until the start of prednisolone (PSL) administration, after which it remarkably improved. The neuropathy further improved after allogeneic bone marrow transplantation (BMT). The present patient's clinical course is not consistent with that of typical Guillain-Barré syndrome. This case suggests that EBV-T/NK-LPD can cause progressive immune-mediated neuropathy as a result of chronic EBV antigen presentation and can be treated with PSL and BMT.

  13. T Cell-Mediated Immunity towards Yellow Fever Virus and Useful Animal Models

    Science.gov (United States)

    Watson, Alan M.; Klimstra, William B.

    2017-01-01

    The 17D line of yellow fever virus vaccines is among the most effective vaccines ever created. The humoral and cellular immunity elicited by 17D has been well characterized in humans. Neutralizing antibodies have long been known to provide protection against challenge with a wild-type virus. However, a well characterized T cell immune response that is robust, long-lived and polyfunctional is also elicited by 17D. It remains unclear whether this arm of immunity is protective following challenge with a wild-type virus. Here we introduce the 17D line of yellow fever virus vaccines, describe the current state of knowledge regarding the immunity directed towards the vaccines in humans and conclude with a discussion of animal models that are useful for evaluating T cell-mediated immune protection to yellow fever virus. PMID:28398253

  14. Differentiation, distribution and gammadelta T cell-driven regulation of IL-22-producing T cells in tuberculosis.

    Directory of Open Access Journals (Sweden)

    Shuyu Yao

    2010-02-01

    Full Text Available Differentiation, distribution and immune regulation of human IL-22-producing T cells in infections remain unknown. Here, we demonstrated in a nonhuman primate model that M. tuberculosis infection resulted in apparent increases in numbers of T cells capable of producing IL-22 de novo without in vitro Ag stimulation, and drove distribution of these cells more dramatically in lungs than in blood and lymphoid tissues. Consistently, IL-22-producing T cells were visualized in situ in lung tuberculosis (TB granulomas by confocal microscopy and immunohistochemistry, indicating that mature IL-22-producing T cells were present in TB granuloma. Surprisingly, phosphoantigen HMBPP activation of Vgamma2Vdelta2 T cells down-regulated the capability of T cells to produce IL-22 de novo in lymphocytes from blood, lung/BAL fluid, spleen and lymph node. Up-regulation of IFNgamma-producing Vgamma2Vdelta2 T effector cells after HMBPP stimulation coincided with the down-regulated capacity of these T cells to produce IL-22 de novo. Importantly, anti-IFNgamma neutralizing Ab treatment reversed the HMBPP-mediated down-regulation effect on IL-22-producing T cells, suggesting that Vgamma2Vdelta2 T-cell-driven IFNgamma-networking function was the mechanism underlying the HMBPP-mediated down-regulation of the capability of T cells to produce IL-22. These novel findings raise the possibility to ultimately investigate the function of IL-22 producing T cells and to target Vgamma2Vdelta2 T cells for balancing potentially hyper-activating IL-22-producing T cells in severe TB.

  15. Sporothrix schenckii Immunization, but Not Infection, Induces Protective Th17 Responses Mediated by Circulating Memory CD4+ T Cells

    Directory of Open Access Journals (Sweden)

    Alberto García-Lozano

    2018-06-01

    Full Text Available Sporotrichosis is a chronic subcutaneous mycosis caused by the Sporothrix schenckii species complex and it is considered an emerging opportunistic infection in countries with tropical and subtropical climates. The host’s immune response has a main role in the development of this disease. However, it is unknown the features of the memory cellular immune response that could protect against the infection. Our results show that i.d. immunization in the ears of mice with inactivated S. schenckii conidia (iC combined with the cholera toxin (CT induces a cellular immune response mediated by circulating memory CD4+ T cells, which mainly produce interleukin 17 (IL-17. These cells mediate a strong delayed-type hypersensitivity (DTH reaction. Systemic and local protection against S. schenckii was mediated by circulating CD4+ T cells. In contrast, the infection induces a potent immune response in the skin mediated by CD4+ T cells, which have an effector phenotype that preferentially produce interferon gamma (IFN-γ and mediate a transitory DTH reaction. Our findings prove the potential value of the CT as a potent skin adjuvant when combined with fungal antigens, and they also have important implications for our better understanding of the differences between the memory immune response induced by the skin immunization and those induced by the infection; this knowledge enhances our understanding of how a protective immune response against a S. schenckii infection is developed.

  16. The interleukin-15 system suppresses T cell-mediated autoimmunity by regulating negative selection and nT(H)17 cell homeostasis in the thymus.

    Science.gov (United States)

    Hou, Mau-Sheng; Huang, Shih-Ting; Tsai, Ming-Han; Yen, Ching-Cheng; Lai, Yein-Gei; Liou, Yae-Huei; Lin, Chih-Kung; Liao, Nan-Shih

    2015-01-01

    The interleukin-15 (IL-15) system is important for regulating both innate and adaptive immune responses, however, its role in autoimmune disease remained unclear. Here we found that Il15(-/-) and Il15ra(-/-) mice spontaneously developed late-onset autoimmune phenotypes. CD4(+) T cells of the knockout mice showed elevated autoreactivity as demonstrated by the induction of lymphocyte infiltration in the lacrimal and salivary glands when transferred into nude mice. The antigen-presenting cells in the thymic medullary regions expressed IL-15 and IL-15Rα, whose deficiency resulted in insufficient negative selection and elevated number of natural IL-17A-producing CD4(+) thymocytes. These findings reveal previously unknown functions of the IL-15 system in thymocyte development, and thus a new layer of regulation in T cell-mediated autoimmunity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Ornamental comb colour predicts T-cell-mediated immunity in male red grouse Lagopus lagopus scoticus

    Science.gov (United States)

    Mougeot, Francois

    2008-02-01

    Sexual ornaments might reliably indicate the ability to cope with parasites and diseases, and a better ability to mount a primary inflammatory response to a novel challenge. Carotenoid-based ornaments are amongst the commonest sexual signals of birds and often influence mate choice. Because carotenoids are immuno-stimulants, signallers may trade-off allocating these to ornamental colouration or using them for immune responses, so carotenoid-based ornaments might be particularly useful as honest indicators of immuno-compentence. Tetraonid birds, such as the red grouse Lagopus lagopus scoticus, exhibit supra-orbital yellow red combs, a conspicuous ornament which functions in intra- and inter-sexual selection. The colour of combs is due to epidermal pigmentation by carotenoids, while their size is testosterone-dependent. In this study, I investigated whether comb characteristics, and in particular, comb colour, indicated immuno-competence in free-living male red grouse. I assessed T-cell-mediated immunity using a standardised challenge with phytohaemagglutinin. Red grouse combs reflect in the red and in the ultraviolet spectrum of light, which is not visible to humans but that grouse most likely see, so I measured comb colour across the whole bird visible spectrum (300 700 nm) using a reflectance spectrometer. I found that males with bigger and redder combs, but with less ultraviolet reflectance, had greater T-cell-mediated immune response. Comb colour predicted T-cell-mediated immune response better than comb size, indicating that the carotenoid-based colouration of this ornament might reliably signal this aspect of male quality.

  18. Chimeric Antigen Receptor T Cell (Car T Cell Therapy In Hematology

    Directory of Open Access Journals (Sweden)

    Pinar Ataca

    2015-12-01

    Full Text Available It is well demonstrated that immune system can control and eliminate cancer cells. Immune-mediated elimination of tumor cells has been discovered and is the basis of both cancer vaccines and cellular therapies including hematopoietic stem cell transplantation (HSCT. Adoptive T cell transfer has been improved to be more specific and potent and cause less off-target toxicities. Currently, there are two forms of engineered T cells being tested in clinical trials: T cell receptor (TCR and chimeric antigen receptor (CAR modified T cells. On July 1, 2014, the United States Food and Drug Administration granted ‘breakthrough therapy’ designation to anti-CD19 CAR T cell therapy. Many studies were conducted to evaluate the beneficiaries of this exciting and potent new treatment modality. This review summarizes the history of adoptive immunotherapy, adoptive immunotherapy using CARs, the CAR manufacturing process, preclinical-clinical studies, effectiveness and drawbacks of this strategy.

  19. Metabolic Adaptation of Human CD4+ and CD8+ T-Cells to T-Cell Receptor-Mediated Stimulation

    Directory of Open Access Journals (Sweden)

    Nicholas Jones

    2017-11-01

    Full Text Available Linking immunometabolic adaptation to T-cell function provides insight for the development of new therapeutic approaches in multiple disease settings. T-cell activation and downstream effector functions of CD4+ and CD8+ T-cells are controlled by the strength of interaction between the T-cell receptor (TCR and peptides presented by human leukocyte antigens (pHLA. The role of TCR–pHLA interactions in modulating T-cell metabolism is unknown. Here, for the first time, we explore the relative contributions of the main metabolic pathways to functional responses in human CD4+ and CD8+ T-cells. Increased expression of hexokinase II accompanied by higher basal glycolysis is demonstrated in CD4+ T-cells; cytokine production in CD8+ T-cells is more reliant on oxidative phosphorylation. Using antigen-specific CD4+ and CD8+ T-cell clones and altered peptide ligands, we demonstrate that binding affinity tunes the underlying metabolic shift. Overall, this study provides important new insight into how metabolic pathways are controlled during antigen-specific activation of human T-cells.

  20. Clonal expansion of renal cell carcinoma-infiltrating T lymphocytes

    DEFF Research Database (Denmark)

    Sittig, Simone; Køllgaard, Tania; Grønbæk, Kirsten

    2013-01-01

    T lymphocytes can mediate the destruction of cancer cells by virtue of their ability to recognize tumor-derived antigenic peptides that are presented on the cell surface in complex with HLA molecules and expand. Thus, the presence of clonally expanded T cells within neoplastic lesions is an indic......T lymphocytes can mediate the destruction of cancer cells by virtue of their ability to recognize tumor-derived antigenic peptides that are presented on the cell surface in complex with HLA molecules and expand. Thus, the presence of clonally expanded T cells within neoplastic lesions...... is an indication of ongoing HLA-restricted T cell-mediated immune responses. Multiple tumors, including renal cell carcinomas (RCCs), are often infiltrated by significant amounts of T cells, the so-called tumor-infiltrating lymphocytes (TILs). In the present study, we analyzed RCC lesions (n = 13) for the presence...... of expanded T-cell clonotypes using T-cell receptor clonotype mapping. Surprisingly, we found that RCCs comprise relatively low numbers of distinct expanded T-cell clonotypes as compared with melanoma lesions. The numbers of different T-cell clonotypes detected among RCC-infiltrating lymphocytes were...

  1. T-cell help permits memory CD8(+) T-cell inflation during cytomegalovirus latency.

    Science.gov (United States)

    Walton, Senta M; Torti, Nicole; Mandaric, Sanja; Oxenius, Annette

    2011-08-01

    CD4(+) T cells are implied to sustain CD8(+) T-cell responses during persistent infections. As CD4(+) T cells are often themselves antiviral effectors, they might shape CD8(+) T-cell responses via help or via controlling antigen load. We used persistent murine CMV (MCMV) infection to dissect the impact of CD4(+) T cells on virus-specific CD8(+) T cells, distinguishing between increased viral load in the absence of CD4(+) T cells and CD4(+) T-cell-mediated helper mechanisms. Absence of T-helper cells was associated with sustained lytic MCMV replication and led to a slow and gradual reduction of the size and function of the MCMV-specific CD8(+) T-cell pool. However, when virus replication was controlled in the absence of CD4(+) T cells, CD8(+) T-cell function was comparably impaired, but in addition CD8(+) T-cell inflation, a hallmark of CMV infection, was completely abolished. Thus, CD8(+) T-cell inflation during latent CMV infection is strongly dependent on CD4(+) T-cell helper functions, which can partially be compensated by ongoing lytic viral replication in the absence of CD4(+) T cells. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. CD8+ T Cell-Mediated Immunity during Trypanosoma cruzi Infection: A Path for Vaccine Development?

    Directory of Open Access Journals (Sweden)

    Fernando dos Santos Virgilio

    2014-01-01

    Full Text Available MHC-restricted CD8+ T cells are important during infection with the intracellular protozoan parasite Trypanosoma cruzi, the causative agent of Chagas disease. Experimental studies performed in the past 25 years have elucidated a number of features related to the immune response mediated by these T cells, which are important for establishing the parasite/host equilibrium leading to chronic infection. CD8+ T cells are specific for highly immunodominant antigens expressed by members of the trans-sialidase family. After infection, their activation is delayed, and the cells display a high proliferative activity associated with high apoptotic rates. Although they participate in parasite control and elimination, they are unable to clear the infection due to their low fitness, allowing the parasite to establish the chronic phase when these cells then play an active role in the induction of heart immunopathology. Vaccination with a number of subunit recombinant vaccines aimed at eliciting specific CD8+ T cells can reverse this path, thereby generating a productive immune response that will lead to the control of infection, reduction of symptoms, and reduction of disease transmission. Due to these attributes, activation of CD8+ T lymphocytes may constitute a path for the development of a veterinarian or human vaccine.

  3. Regulatory T-cells and autoimmunity.

    LENUS (Irish Health Repository)

    Ni Choileain, Niamh

    2012-02-03

    Approximately 20% of the population is affected by autoimmune or inflammatory diseases mediated by an abnormal immune response. A characteristic feature of autoimmune disease is the selective targeting of a single cell type, organ or tissue by certain populations of autoreactive T-cells. Examples of such diseases include rheumatoid arthritis, insulin-dependent diabetes mellitus, and systemic lupus erythematosus (SLE), all of which are characterized by chronic inflammation, tissue destruction and target organ malfunction. Although strong evidence links most autoimmune diseases to specific genes, considerable controversy prevails regarding the role of regulatory T-cell populations in the disease process. These cells are now also believed to play a key role in mediating transplantation tolerance and inhibiting the induction of tumor immunity. Though the concept of therapeutic immune regulation aimed at treating autoimmune pathology has been validated in many animal models, the development of strategies for the treatment of human autoimmune disorders remains in its infancy. The main obstacles to this include the conflicting findings of different model systems, as well as the contrasting functions of regulatory T-cells and cytokines involved in the development of such disorders. This review examines the role of regulatory T-cells in the pathogenesis of autoimmunity and describes the therapeutic potential of these cells for the prevention of immune-mediated pathologies in the future. Although much remains to be learned about such pathologies, a clearer understanding of the mechanisms by which regulatory T-cells function will undoubtedly lead to exciting new possibilities for immunotherapeutics.

  4. Mechanisms of Acquired Resistance to Trastuzumab Emtansine in Breast Cancer Cells.

    Science.gov (United States)

    Li, Guangmin; Guo, Jun; Shen, Ben-Quan; Bumbaca Yadav, Daniela; Sliwkowski, Mark X; Crocker, Lisa M; Lacap, Jennifer A; Lewis Phillips, Gail D

    2018-04-25

    The receptor tyrosine kinase HER2 is overexpressed in approximately 20% of breast cancer, and its amplification is associated with reduced survival. Trastuzumab emtansine (Kadcyla®, T-DM1), an antibody-drug conjugate that is comprised of trastuzumab covalently linked to the anti-mitotic agent DM1 through a stable linker, was designed to selectively deliver DM1 to HER2-overexpressing tumor cells. T-DM1 is approved for the treatment of patients with HER2-positive metastatic breast cancer following progression on trastuzumab and a taxane. Despite the improvement in clinical outcome, many patients who initially respond to T-DM1 treatment eventually develop progressive disease. The mechanisms that contribute to T-DM1 resistance are not fully understood. To this end, we developed T-DM1-resistant in vitro models to examine the mechanisms of acquired T-DM1 resistance. We demonstrate that decreased HER2 and up-regulation of MDR1 contribute to T-DM1 resistance in KPL-4 T-DM1 resistant cells. In contrast, both loss of SLC46A3 and PTEN deficiency play a role in conferring resistance in BT-474M1 T-DM1 resistant cells. Our data suggest that these two cell lines acquire resistance through distinct mechanisms. Furthermore, we show that the KPL-4 T-DM1 resistance can be overcome by treatment with an inhibitor of MDR1, whereas a PI3K inhibitor can rescue PTEN loss-induced resistance in T-DM1-resistant BT-474M1 cells. Our results provide a rationale for developing therapeutic strategies to enhance T-DM1 clinical efficacy by combining T-DM1 and other inhibitors that target signaling transduction or resistance pathways. Copyright ©2018, American Association for Cancer Research.

  5. Surfactant protein D delays Fas- and TRAIL-mediated extrinsic pathway of apoptosis in T cells.

    Science.gov (United States)

    Djiadeu, Pascal; Kotra, Lakshmi P; Sweezey, Neil; Palaniyar, Nades

    2017-05-01

    Only a few extracellular soluble proteins are known to modulate apoptosis. We considered that surfactant-associated protein D (SP-D), an innate immune collectin present on many mucosal surfaces, could regulate apoptosis. Although SP-D is known to be important for immune cell homeostasis, whether SP-D affects apoptosis is unknown. In this study we aimed to determine the effects of SP-D on Jurkat T cells and human T cells dying by apoptosis. Here we show that SP-D binds to Jurkat T cells and delays the progression of Fas (CD95)-Fas ligand and TRAIL-TRAIL receptor induced, but not TNF-TNF receptor-mediated apoptosis. SP-D exerts its effects by reducing the activation of initiator caspase-8 and executioner caspase-3. SP-D also delays the surface exposure of phosphatidylserine. The effect of SP-D was ablated by the presence of caspase-8 inhibitor, but not by intrinsic pathway inhibitors. The binding ability of SP-D to dying cells decreases during the early stages of apoptosis, suggesting the release of apoptotic cell surface targets during apoptosis. SP-D also delays FasL-induced death of primary human T cells. SP-D delaying the progression of the extrinsic pathway of apoptosis could have important implications in regulating immune cell homeostasis at mucosal surfaces.

  6. Calpain 4 is not necessary for LFA-1-mediated function in CD4+ T cells.

    Directory of Open Access Journals (Sweden)

    Sarah A Wernimont

    2010-05-01

    Full Text Available T cell activation and immune synapse formation require the appropriate activation and clustering of the integrin, LFA-1. Previous work has reported that the calpain family of calcium-dependent proteases are important regulators of integrin activation and modulate T cell adhesion and migration. However, these studies have been limited by the use of calpain inhibitors, which have known off-target effects.Here, we used a LoxP/CRE system to specifically deplete calpain 4, a small regulatory calpain subunit required for expression and activity of ubiquitously expressed calpains 1 and 2, in CD4+ T cells. CD4+ and CD8+ T cells developed normally in Capn4(F/F:CD4-CRE mice and had severely diminished expression of Calpain 1 and 2, diminished talin proteolysis and impaired casein degradation. Calpain 4-deficient T cells showed no difference in adhesion or migration on the LFA-1 ligand ICAM-1 compared to control T cells. Moreover, there was no impairment in conjugation between Capn4(F/F:CD4-CRE T cells and antigen presenting cells, and the conjugates were still capable of polarizing LFA-1, PKC-theta and actin to the immune synapse. Furthermore, T cells from Capn4(F/F:CD4-CRE mice showed normal proliferation in response to either anti-CD3/CD28 coated beads or cognate antigen-loaded splenocytes. Finally, there were no differences in the rates of apoptosis following extrinsic and intrinsic apoptotic stimuli.Our findings demonstrate that calpain 4 is not necessary for LFA-1-mediated adhesion, conjugation or migration. These results challenge previous reports that implicate a central role for calpains in the regulation of T cell LFA-1 function.

  7. Unique ζ-chain motifs mediate a direct TCR-actin linkage critical for immunological synapse formation and T-cell activation.

    Science.gov (United States)

    Klieger, Yair; Almogi-Hazan, Osnat; Ish-Shalom, Eliran; Pato, Aviad; Pauker, Maor H; Barda-Saad, Mira; Wang, Lynn; Baniyash, Michal

    2014-01-01

    TCR-mediated activation induces receptor microclusters that evolve to a defined immune synapse (IS). Many studies showed that actin polymerization and remodeling, which create a scaffold critical to IS formation and stabilization, are TCR mediated. However, the mechanisms controlling simultaneous TCR and actin dynamic rearrangement in the IS are yet not fully understood. Herein, we identify two novel TCR ζ-chain motifs, mediating the TCR's direct interaction with actin and inducing actin bundling. While T cells expressing the ζ-chain mutated in these motifs lack cytoskeleton (actin) associated (cska)-TCRs, they express normal levels of non-cska and surface TCRs as cells expressing wild-type ζ-chain. However, such mutant cells are unable to display activation-dependent TCR clustering, IS formation, expression of CD25/CD69 activation markers, or produce/secrete cytokine, effects also seen in the corresponding APCs. We are the first to show a direct TCR-actin linkage, providing the missing gap linking between TCR-mediated Ag recognition, specific cytoskeleton orientation toward the T-cell-APC interacting pole and long-lived IS maintenance. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Plasmodium falciparum-mediated induction of human CD25Foxp3 CD4 T cells is independent of direct TCR stimulation and requires IL-2, IL-10 and TGFbeta.

    Directory of Open Access Journals (Sweden)

    Anja Scholzen

    2009-08-01

    Full Text Available CD4(+CD25(+Foxp3(+ regulatory T cells (Tregs regulate disease-associated immunity and excessive inflammatory responses, and numbers of CD4(+CD25(+Foxp3(+ Tregs are increased during malaria infection. The mechanisms governing their generation, however, remain to be elucidated. In this study we investigated the role of commonly accepted factors for Foxp3 induction, TCR stimulation and cytokines such as IL-2, TGFbeta and IL-10, in the generation of human CD4(+CD25(+Foxp3(+ T cells by the malaria parasite Plasmodium falciparum. Using a co-culture system of malaria-infected red blood cells (iRBCs and peripheral blood mononuclear cells from healthy individuals, we found that two populations of Foxp3(hi and Foxp3(int CD4(+CD25(hi T cells with a typical Treg phenotype (CTLA-4(+, CD127(low, CD39(+, ICOS(+, TNFRII(+ were induced. Pro-inflammatory cytokine production was confined to the Foxp3(int subset (IFNgamma, IL-4 and IL-17 and inversely correlated with high relative levels of Foxp3(hi cells, consistent with Foxp3(hi CD4 T cell-mediated inhibition of parasite-induced effector cytokine T cell responses. Both Foxp3(hi and Foxp3(int cells were derived primarily from proliferating CD4(+CD25(- T cells with a further significant contribution from CD25(+Foxp3(+ natural Treg cells to the generation of the Foxp3(hi subset. Generation of Foxp3(hi, but not Foxp3(int, cells specifically required TGFbeta1 and IL-10. Add-back experiments showed that monocytes expressing increased levels of co-stimulatory molecules were sufficient for iRBC-mediated induction of Foxp3 in CD4 T cells. Foxp3 induction was driven by IL-2 from CD4 T cells stimulated in an MHC class II-dependent manner. However, transwell separation experiments showed that direct contact of monocytes with the cells that acquire Foxp3 expression was not required. This novel TCR-independent and therefore antigen-non specific mechanism for by-stander CD4(+CD25(hiFoxp3(+ cell induction is likely to reflect a

  9. Direct and Indirect Effects of Cytomegalovirus-induced gamma-delta T Cells after Kidney Transplantation

    Directory of Open Access Journals (Sweden)

    Lionel eCouzi

    2015-01-01

    Full Text Available Despite effective anti-viral therapies, cytomegalovirus (CMV is still associated with direct (CMV disease and indirect effects (rejection and poor graft survival in kidney transplant recipients. Recently, an unconventional T cell population (collectively designated as Vδ2neg γδ T cells has been characterized during the anti-CMV immune response in all solid-organ and bone-marrow transplant recipients, neonates, and healthy people. These CMV-induced γδ T cells undergo a dramatic and stable expansion after CMV infection, in a conventional ‘adaptive’ manner. Similarly as CMV-specific CD8+ αβ T cells, they exhibit an effector/memory TEMRA phenotype and cytotoxic effector functions. Activation of Vd2neg gd T cells by CMV-infected cells involves the TCR and still ill-defined co-stimulatory molecules such LFA-1. A multiple of Vd2neg gd TCR ligands are apparently recognized on CMV-infected cells, the first one identified being the MHC-related molecule endothelial protein C receptor (EPCR. A singularity of CMV-induced Vd2neg gd T cells is to acquire CD16 expression and to exert an antibody-dependent cell-mediated inhibition on CMV replication, which is controlled by a specific cytokine microenvironment. Beyond the well-demonstrated direct anti-CMV effect of Vδ2neg γδ T cells, unexpected indirect effects of these cells have been also observed in the context of kidney transplantation. CMV-induced Vδ2neg γδ T cells have been involved in surveillance of malignancy subsequent to long term immunosuppression. Moreover, CMV-induced CD16+ γδ T cells are cell effectors of antibody-mediated rejection of kidney transplants, and represent a new physiopathological contribution to the well-known association between CMV infection and poor graft survival. All these basic and clinical studies paved the road to the development of a future γδ T cell-based immunotherapy. In the meantime, γδ T cell monitoring should prove a valuable immunological

  10. T cell receptor (TCR-transgenic CD8 lymphocytes rendered insensitive to transforming growth factor beta (TGFβ signaling mediate superior tumor regression in an animal model of adoptive cell therapy

    Directory of Open Access Journals (Sweden)

    Quatromoni Jon G

    2012-06-01

    Full Text Available Abstract Tumor antigen-reactive T cells must enter into an immunosuppressive tumor microenvironment, continue to produce cytokine and deliver apoptotic death signals to affect tumor regression. Many tumors produce transforming growth factor beta (TGFβ, which inhibits T cell activation, proliferation and cytotoxicity. In a murine model of adoptive cell therapy, we demonstrate that transgenic Pmel-1 CD8 T cells, rendered insensitive to TGFβ by transduction with a TGFβ dominant negative receptor II (DN, were more effective in mediating regression of established B16 melanoma. Smaller numbers of DN Pmel-1 T cells effectively mediated tumor regression and retained the ability to produce interferon-γ in the tumor microenvironment. These results support efforts to incorporate this DN receptor in clinical trials of adoptive cell therapy for cancer.

  11. CD147 and CD98 complex-mediated homotypic aggregation attenuates the CypA-induced chemotactic effect on Jurkat T cells.

    Science.gov (United States)

    Guo, Na; Zhang, Kui; Lv, Minghua; Miao, Jinlin; Chen, Zhinan; Zhu, Ping

    2015-02-01

    Homotypic cell aggregation plays important roles in physiological and pathological processes, including embryogenesis, immune responses, angiogenesis, tumor cell invasion and metastasis. CD147 has been implicated in most of these phenomena, and it was identified as a T cell activation-associated antigen due to its obvious up-regulation in activated T cells. However, the explicit function and mechanism of CD147 in T cells have not been fully elucidated. In this study, large and compact aggregates were observed in Jurkat T cells after treatment with the specific CD147 monoclonal antibody HAb18 or after the expression of CD147 was silenced by RNA interference, which indicated an inhibitory effect of CD147 in T cell homotypic aggregation. Knocking down CD147 expression resulted in a significant decrease in CD98, along with prominent cell aggregation, similar to that treated by CD98 and CD147 monoclonal antibodies. Furthermore, decreased cell chemotactic activity was observed following CD147- and CD98-mediated cell aggregation, and increased aggregation was correlated with a decrease in the chemotactic ability of the Jurkat T cells, suggesting that CD147- and CD98-mediated homotypic cell aggregation plays a negative role in T cell chemotaxis. Our data also showed that p-ERK, p-ZAP70, p-CD3ζ and p-LCK were significantly decreased in the CD147- and CD98-knocked down Jurkat T cells, which suggested that decreased CD147- and/or CD98-induced homotypic T cell aggregation and aggregation-inhibited chemotaxis might be associated with these signaling pathways. A role for CD147 in cell aggregation and chemotaxis was further indicated in primary CD4(+) T cells. Similarly, low expression of CD147 in primary T cells induced prominent cell aggregation and this aggregation attenuated primary T cell chemotactic ability in response to CypA. Our results have demonstrated the correlation between homotypic cell aggregation and the chemotactic response of T cells to CypA, and these data

  12. The role of monocytes and T cells in 1,25-dihydroxyvitamin D3 mediated inhibition of B cell function in vitro

    DEFF Research Database (Denmark)

    Müller, K; Heilmann, C; Poulsen, L K

    1991-01-01

    1,25-Dihydroxyvitamin D3 (1,25-(OH)2D3) inhibits immunoglobulin production by human mononuclear cells (MNC) in vitro. The present study was undertaken to evaluate the role of T cells and monocytes in 1,25-(OH)2D3 induced suppression of B cell functions. The synthetic vitamin D3 analogue MC 903...... was examined in parallel. 1,25-(OH)2D3 and MC 903 showed a dose-related inhibition of IgM, IgG and IgA plaque-forming cells in poke-weed mitogen (PWM) activated cultures of MNC. This effect was most likely mediated through impairment of T cell and monocyte functions. First, the inhibitory effect was seen after...

  13. Low doses of cholera toxin and its mediator cAMP induce CTLA-2 secretion by dendritic cells to enhance regulatory T cell conversion.

    Directory of Open Access Journals (Sweden)

    Cinthia Silva-Vilches

    Full Text Available Immature or semi-mature dendritic cells (DCs represent tolerogenic maturation stages that can convert naive T cells into Foxp3+ induced regulatory T cells (iTreg. Here we found that murine bone marrow-derived DCs (BM-DCs treated with cholera toxin (CT matured by up-regulating MHC-II and costimulatory molecules using either high or low doses of CT (CThi, CTlo or with cAMP, a known mediator CT signals. However, all three conditions also induced mRNA of both isoforms of the tolerogenic molecule cytotoxic T lymphocyte antigen 2 (CTLA-2α and CTLA-2β. Only DCs matured under CThi conditions secreted IL-1β, IL-6 and IL-23 leading to the instruction of Th17 cell polarization. In contrast, CTlo- or cAMP-DCs resembled semi-mature DCs and enhanced TGF-β-dependent Foxp3+ iTreg conversion. iTreg conversion could be reduced using siRNA blocking of CTLA-2 and reversely, addition of recombinant CTLA-2α increased iTreg conversion in vitro. Injection of CTlo- or cAMP-DCs exerted MOG peptide-specific protective effects in experimental autoimmune encephalomyelitis (EAE by inducing Foxp3+ Tregs and reducing Th17 responses. Together, we identified CTLA-2 production by DCs as a novel tolerogenic mediator of TGF-β-mediated iTreg induction in vitro and in vivo. The CT-induced and cAMP-mediated up-regulation of CTLA-2 also may point to a novel immune evasion mechanism of Vibrio cholerae.

  14. The phosphorylation state of CD3gamma influences T cell responsiveness and controls T cell receptor cycling

    DEFF Research Database (Denmark)

    Dietrich, J; Bäckström, T; Lauritsen, J P

    1998-01-01

    The T cell receptor (TCR) is internalized following activation of protein kinase C (PKC) via a leucine (Leu)-based motif in CD3gamma. Some studies have indicated that the TCR is recycled back to the cell surface following PKC-mediated internalization. The functional state of recycled TCR and the ......The T cell receptor (TCR) is internalized following activation of protein kinase C (PKC) via a leucine (Leu)-based motif in CD3gamma. Some studies have indicated that the TCR is recycled back to the cell surface following PKC-mediated internalization. The functional state of recycled TCR...... the phosphorylation state of CD3gamma and T cell responsiveness. Based on these observations a physiological role of CD3gamma and TCR cycling is proposed....

  15. Apoptosis and T cell depletion during feline infectious peritonitis

    OpenAIRE

    Horzinek, M.C.; Haagmans, B.L.; Egberink, H.F.

    1996-01-01

    Cats that have succumbed to feline infectious peritonitis, an immune- mediated disease caused by variants of feline coronaviruses, show apoptosis and T-cell depletion in their lymphoid organs. The ascitic fluid that develops in the course of the condition causes apoptosis in vitro but only in activated T cells. Since feline infectious peritonitis virus does not infect T cells, and viral proteins did not inhibit T-cell proliferation, we postulate that soluble mediators released during the infe...

  16. Antigen-specific cytotoxic T cell and antigen-specific proliferating T cell clones can be induced to cytolytic activity by monoclonal antibodies against T3

    NARCIS (Netherlands)

    Spits, H.; Yssel, H.; Leeuwenberg, J.; de Vries, J. E.

    1985-01-01

    T3 is a human differentiation antigen expressed exclusively on mature T cells. In this study it is shown that anti-T3 monoclonal antibodies, in addition to their capacity to induce T cells to proliferate, are able to induce antigen-specific cytotoxic T lymphocyte clones to mediate antigen

  17. Severe Malaria Infections Impair Germinal Center Responses by Inhibiting T Follicular Helper Cell Differentiation

    Directory of Open Access Journals (Sweden)

    Victoria Ryg-Cornejo

    2016-01-01

    Full Text Available Naturally acquired immunity to malaria develops only after years of repeated exposure to Plasmodium parasites. Despite the key role antibodies play in protection, the cellular processes underlying the slow acquisition of immunity remain unknown. Using mouse models, we show that severe malaria infection inhibits the establishment of germinal centers (GCs in the spleen. We demonstrate that infection induces high frequencies of T follicular helper (Tfh cell precursors but results in impaired Tfh cell differentiation. Despite high expression of Bcl-6 and IL-21, precursor Tfh cells induced during infection displayed low levels of PD-1 and CXCR5 and co-expressed Th1-associated molecules such as T-bet and CXCR3. Blockade of the inflammatory cytokines TNF and IFN-γ or T-bet deletion restored Tfh cell differentiation and GC responses to infection. Thus, this study demonstrates that the same pro-inflammatory mediators that drive severe malaria pathology have detrimental effects on the induction of protective B cell responses.

  18. Caspase-dependant activation of chymotrypsin-like proteases mediates nuclear events during Jurkat T cell apoptosis

    International Nuclear Information System (INIS)

    O'Connell, A.R.; Lee, B.W.; Stenson-Cox, C.

    2006-01-01

    Apoptosis involves a cascade of biochemical and morphological changes resulting in the systematic disintegration of the cell. Caspases are central mediators of this process. Supporting and primary roles for serine proteases as pro-apoptotic mediators have also been highlighted. Evidence for such roles comes largely from the use of pharmacological inhibitors; as a consequence information regarding their apoptotic function and biochemical properties has been limited. Here, we circumvented limitations associated with traditional serine protease inhibitors through use of a fluorescently labelled inhibitor of serine proteases (FLISP) that allowed for analysis of the specificity, regulation and positioning of apoptotic serine proteases within a classical apoptotic cascade. We demonstrate that staurosporine triggers a caspase-dependant induction of chymotrypsin-like activity in the nucleus of apoptotic Jurkat T cells. We show that serine protease activity is required for the generation of late stage nuclear events including condensation, fragmentation and DNA degradation. Furthermore, we reveal caspase-dependant activation of two chymotrypsin-like protein species that we hypothesize mediate cell death-associated nuclear events

  19. Antigen localization controls T cell-mediated tumor immunity.

    Science.gov (United States)

    Zeelenberg, Ingrid S; van Maren, Wendy W C; Boissonnas, Alexandre; Van Hout-Kuijer, Maaike A; Den Brok, Martijn H M G M; Wagenaars, Jori A L; van der Schaaf, Alie; Jansen, Eric J R; Amigorena, Sebastian; Théry, Clotilde; Figdor, Carl G; Adema, Gosse J

    2011-08-01

    Effective antitumor immunotherapy requires the identification of suitable target Ags. Interestingly, many of the tumor Ags used in clinical trials are present in preparations of secreted tumor vesicles (exosomes). In this study, we compared T cell responses elicited by murine MCA101 fibrosarcoma tumors expressing a model Ag at different localizations within the tumor cell in association with secreted vesicles (exosomes), as a nonsecreted cell-associated protein, or as secreted soluble protein. Remarkably, we demonstrated that only the tumor-secreting vesicle-bound Ag elicited a strong Ag-specific CD8(+) T cell response, CD4(+) T cell help, Ag-specific Abs, and a decrease in the percentage of immunosuppressive regulatory T cells in the tumor. Moreover, in a therapeutic tumor model of cryoablation, only in tumors secreting vesicle-bound Ag could Ag-specific CD8(+) T cells still be detected up to 16 d after therapy. We concluded that the localization of an Ag within the tumor codetermines whether a robust immunostimulatory response is elicited. In vivo, vesicle-bound Ag clearly skews toward a more immunogenic phenotype, whereas soluble or cell-associated Ag expression cannot prevent or even delay outgrowth and results in tumor tolerance. This may explain why particular immunotherapies based on these vesicle-bound tumor Ags are potentially successful. Therefore, we conclude that this study may have significant implications in the discovery of new tumor Ags suitable for immunotherapy and that their location should be taken into account to ensure a strong antitumor immune response.

  20. Genetic Associations in Acquired Immune-Mediated Bone Marrow Failure Syndromes: Insights in Aplastic Anemia and Chronic Idiopathic Neutropenia

    Science.gov (United States)

    Mavroudi, Irene; Papadaki, Helen A.

    2012-01-01

    Increasing interest on the field of autoimmune diseases has unveiled a plethora of genetic factors that predispose to these diseases. However, in immune-mediated bone marrow failure syndromes, such as acquired aplastic anemia and chronic idiopathic neutropenia, in which the pathophysiology results from a myelosuppressive bone marrow microenvironment mainly due to the presence of activated T lymphocytes, leading to the accelerated apoptotic death of the hematopoietic stem and progenitor cells, such genetic associations have been very limited. Various alleles and haplotypes of human leucocyte antigen (HLA) molecules have been implicated in the predisposition of developing the above diseases, as well as polymorphisms of inhibitory cytokines such as interferon-γ, tumor necrosis factor-α, and transforming growth factor-β1 along with polymorphisms on molecules of the immune system including the T-bet transcription factor and signal transducers and activators of transcription. In some cases, specific polymorphisms have been implicated in the outcome of treatment on those patients. PMID:22956967

  1. Chronically Elevated Levels of Short-Chain Fatty Acids Induce T Cell-Mediated Ureteritis and Hydronephrosis.

    Science.gov (United States)

    Park, Jeongho; Goergen, Craig J; HogenEsch, Harm; Kim, Chang H

    2016-03-01

    Short-chain fatty acids (SCFAs) are major products of gut microbial fermentation and profoundly affect host health and disease. SCFAs generate IL-10(+) regulatory T cells, which may promote immune tolerance. However, SCFAs can also induce Th1 and Th17 cells upon immunological challenges and, therefore, also have the potential to induce inflammatory responses. Because of the seemingly paradoxical SCFA activities in regulating T cells, we investigated, in depth, the impact of elevated SCFA levels on T cells and tissue inflammation in mice. Orally administered SCFAs induced effector (Th1 and Th17) and regulatory T cells in ureter and kidney tissues, and they induced T cell-mediated ureteritis, leading to kidney hydronephrosis (hereafter called acetate-induced renal disease, or C2RD). Kidney hydronephrosis in C2RD was caused by ureteral obstruction, which was, in turn, induced by SCFA-induced inflammation in the ureteropelvic junction and proximal ureter. Oral administration of all major SCFAs, such as acetate, propionate, and butyrate, induced the disease. We found that C2RD development is dependent on mammalian target of rapamycin activation, T cell-derived inflammatory cytokines such as IFN-γ and IL-17, and gut microbiota. Young or male animals were more susceptible than old or female animals, respectively. However, SCFA receptor (GPR41 or GPR43) deficiency did not affect C2RD development. Thus, SCFAs, when systemically administered at levels higher than physiological levels, cause dysregulated T cell responses and tissue inflammation in the renal system. The results provide insights into the immunological and pathological effects of chronically elevated SCFAs. Copyright © 2016 by The American Association of Immunologists, Inc.

  2. Activated T cells sustain myeloid-derived suppressor cell-mediated immune suppression

    Science.gov (United States)

    Damuzzo, Vera; Francescato, Samuela; Pozzuoli, Assunta; Berizzi, Antonio; Mocellin, Simone; Rossi, Carlo Riccardo; Bronte, Vincenzo; Mandruzzato, Susanna

    2016-01-01

    The expansion of myeloid derived suppressor cells (MDSCs), a suppressive population able to hamper the immune response against cancer, correlates with tumor progression and overall survival in several cancer types. We have previously shown that MDSCs can be induced in vitro from precursors present in the bone marrow and observed that these cells are able to actively proliferate in the presence of activated T cells, whose activation level is critical to drive the suppressive activity of MDSCs. Here we investigated at molecular level the mechanisms involved in the interplay between MDSCs and activated T cells. We found that activated T cells secrete IL-10 following interaction with MDSCs which, in turn, activates STAT3 phosphorylation on MDSCs then leading to B7-H1 expression. We also demonstrated that B7-H1+ MDSCs are responsible for immune suppression through a mechanism involving ARG-1 and IDO expression. Finally, we show that the expression of ligands B7-H1 and MHC class II both on in vitro-induced MDSCs and on MDSCs in the tumor microenvironment of cancer patients is paralleled by an increased expression of their respective receptors PD-1 and LAG-3 on T cells, two inhibitory molecules associated with T cell dysfunction. These findings highlight key molecules and interactions responsible for the extensive cross-talk between MDSCs and activated T cells that are at the basis of immune suppression. PMID:26700461

  3. CD4+ T cell effects on CD8+ T cell location defined using bioluminescence.

    Directory of Open Access Journals (Sweden)

    Mitra Azadniv

    2011-01-01

    Full Text Available T lymphocytes of the CD8+ class are critical in delivering cytotoxic function and in controlling viral and intracellular infections. These cells are "helped" by T lymphocytes of the CD4+ class, which facilitate their activation, clonal expansion, full differentiation and the persistence of memory. In this study we investigated the impact of CD4+ T cells on the location of CD8+ T cells, using antibody-mediated CD4+ T cell depletion and imaging the antigen-driven redistribution of bioluminescent CD8+ T cells in living mice. We documented that CD4+ T cells influence the biodistribution of CD8+ T cells, favoring their localization to abdominal lymph nodes. Flow cytometric analysis revealed that this was associated with an increase in the expression of specific integrins. The presence of CD4+ T cells at the time of initial CD8+ T cell activation also influences their biodistribution in the memory phase. Based on these results, we propose the model that one of the functions of CD4+ T cell "help" is to program the homing potential of CD8+ T cells.

  4. Commensal-induced regulatory T cells mediate protection against pathogen-stimulated NF-kappaB activation.

    Directory of Open Access Journals (Sweden)

    Caitlin O'Mahony

    Full Text Available Host defence against infection requires a range of innate and adaptive immune responses that may lead to tissue damage. Such immune-mediated pathologies can be controlled with appropriate T regulatory (Treg activity. The aim of the present study was to determine the influence of gut microbiota composition on Treg cellular activity and NF-kappaB activation associated with infection. Mice consumed the commensal microbe Bifidobacterium infantis 35624 followed by infection with Salmonella typhimurium or injection with LPS. In vivo NF-kappaB activation was quantified using biophotonic imaging. CD4+CD25+Foxp3+ T cell phenotypes and cytokine levels were assessed using flow cytometry while CD4+ T cells were isolated using magnetic beads for adoptive transfer to naïve animals. In vivo imaging revealed profound inhibition of infection and LPS induced NF-kappaB activity that preceded a reduction in S. typhimurium numbers and murine sickness behaviour scores in B. infantis-fed mice. In addition, pro-inflammatory cytokine secretion, T cell proliferation, and dendritic cell co-stimulatory molecule expression were significantly reduced. In contrast, CD4+CD25+Foxp3+ T cell numbers were significantly increased in the mucosa and spleen of mice fed B. infantis. Adoptive transfer of CD4+CD25+ T cells transferred the NF-kappaB inhibitory activity. Consumption of a single commensal micro-organism drives the generation and function of Treg cells which control excessive NF-kappaB activation in vivo. These cellular interactions provide the basis for a more complete understanding of the commensal-host-pathogen trilogue that contribute to host homeostatic mechanisms underpinning protection against aberrant activation of the innate immune system in response to a translocating pathogen or systemic LPS.

  5. γδ T Cells Support Pancreatic Oncogenesis by Restraining αβ T Cell Activation.

    Science.gov (United States)

    Daley, Donnele; Zambirinis, Constantinos Pantelis; Seifert, Lena; Akkad, Neha; Mohan, Navyatha; Werba, Gregor; Barilla, Rocky; Torres-Hernandez, Alejandro; Hundeyin, Mautin; Mani, Vishnu Raj Kumar; Avanzi, Antonina; Tippens, Daniel; Narayanan, Rajkishen; Jang, Jung-Eun; Newman, Elliot; Pillarisetty, Venu Gopal; Dustin, Michael Loran; Bar-Sagi, Dafna; Hajdu, Cristina; Miller, George

    2016-09-08

    Inflammation is paramount in pancreatic oncogenesis. We identified a uniquely activated γδT cell population, which constituted ∼40% of tumor-infiltrating T cells in human pancreatic ductal adenocarcinoma (PDA). Recruitment and activation of γδT cells was contingent on diverse chemokine signals. Deletion, depletion, or blockade of γδT cell recruitment was protective against PDA and resulted in increased infiltration, activation, and Th1 polarization of αβT cells. Although αβT cells were dispensable to outcome in PDA, they became indispensable mediators of tumor protection upon γδT cell ablation. PDA-infiltrating γδT cells expressed high levels of exhaustion ligands and thereby negated adaptive anti-tumor immunity. Blockade of PD-L1 in γδT cells enhanced CD4(+) and CD8(+) T cell infiltration and immunogenicity and induced tumor protection suggesting that γδT cells are critical sources of immune-suppressive checkpoint ligands in PDA. We describe γδT cells as central regulators of effector T cell activation in cancer via novel cross-talk. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Meta-analysis of the impact of de novo and acquired EGFR T790M mutations on the prognosis of patients with non-small cell lung cancer receiving EGFR-TKIs

    Directory of Open Access Journals (Sweden)

    Liu Y

    2017-04-01

    Full Text Available Yang Liu, Li Sun, Zhi-Cheng Xiong, Xin Sun, Shu-Ling Zhang, Jie-Tao Ma, Cheng-Bo Han Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, People’s Republic of China Purpose: The purpose of this meta-analysis was to explore the influences of pretreatment de novo and posttreatment-acquired epidermal growth factor receptor (EGFR T790M mutations in patients with advanced non-small cell lung cancer (NSCLC who had received tyrosine kinase inhibitors (TKIs.Methods: We searched PubMed, Embase, and the China National Knowledge Infrastructure database for eligible literature. Data were extracted to assess the hazard ratios (HRs for progression-free survival (PFS, overall survival (OS, and post-progression survival (PPS and the relative ratios (RRs for objective response rate (ORR.Results: This meta-analysis included 22 studies comprising 1,462 patients with NSCLC who harbored activating EGFR mutations and were treated with EGFR-TKIs. Compared to pretreatment T790M mutation-negative NSCLC, pretreatment T790M mutation-positive NSCLC was associated with decreased PFS (HR 2.23, P<0.001 and OS (HR 1.55, P=0.003. A trend toward significance of worsening ORR (RR 0.86, P=0.051 was evident. The acquired T790M mutation was correlated with improved PFS (HR 0.75, P=0.006 and PPS (HR 0.57, P<0.001, compared to patients without the T790M mutation who progressed after EGFR-TKI treatment. There were no significant differences in OS or ORR between patients with acquired T790M mutation-positive and T790M mutation-negative NSCLC. However, in the tumor tissue rebiopsy subgroup, patients with acquired T790M mutation had improved OS (HR 0.60, P<0.001 compared to T790M mutation-negative patients. In the plasma ctDNA subgroup, acquired T790M mutation decreased the OS (HR 1.87, P<0.001.Conclusion: Pretreatment T790M mutation was associated with worse PFS and OS in patients with advanced NSCLC treated with EGFR-TKIs, while acquired T790M mutation was

  7. Mast cells enhance T cell activation: Importance of mast cell-derived TNF

    Science.gov (United States)

    Nakae, Susumu; Suto, Hajime; Kakurai, Maki; Sedgwick, Jonathon D.; Tsai, Mindy; Galli, Stephen J.

    2005-05-01

    Mast cells are not only important effector cells in immediate hypersensitivity reactions and immune responses to pathogens but also can contribute to T cell-mediated disorders. However, the mechanisms by which mast cells might influence T cells in such settings are not fully understood. We find that mast cells can enhance proliferation and cytokine production in multiple T cell subsets. Mast cell-dependent enhancement of T cell activation can be promoted by FcRI-dependent mast cell activation, TNF production by both mast cells and T cells, and mast cell-T cell contact. However, at high concentrations of cells, mast cells can promote T cell activation independent of IgE or TNF. Finally, mast cells also can promote T cell activation by means of soluble factors. These findings identify multiple mechanisms by which mast cells can influence T cell proliferation and cytokine production. allergy | asthma | autoimmunity | cytokines | immune response

  8. IL-23 and T(H)17-mediated inflammation in human allergic contact dermatitis

    DEFF Research Database (Denmark)

    Larsen, Jeppe Madura; Bonefeld, Charlotte Menné; Poulsen, Steen Seier

    2009-01-01

    . OBJECTIVE: To investigate T(H)17-mediated inflammation in human beings with allergic contact dermatitis; in particular, the innate response of keratinocytes to contact allergen, the induction of allergen-specific T(H)17 cells, and the presence of T(H)17-related effector cells in inflamed skin. METHODS....... CONCLUSION: Our results demonstrate the involvement of T(H)17-mediated immunopathology in human allergic contact dermatitis, including both innate and adaptive immune responses to contact allergens....

  9. Dietary n-3 PUFA affect TcR-mediated activation of purified murine T cells and accessory cell function in co-cultures

    Science.gov (United States)

    CHAPKIN, R S; ARRINGTON, J L; APANASOVICH, T V; CARROLL, R J; MCMURRAY, D N

    2002-01-01

    Diets enriched in n-3 polyunsaturated fatty acids (PUFA) suppress several functions of murine splenic T cells by acting directly on the T cells and/or indirectly on accessory cells. In this study, the relative contribution of highly purified populations of the two cell types to the dietary suppression of T cell function was examined. Mice were fed diets containing different levels of n-3 PUFA; safflower oil (SAF; control containing no n-3 PUFA), fish oil (FO) at 2% and 4%, or 1% purified docosahexaenoic acid (DHA) for 2 weeks. Purified (>90%) T cells were obtained from the spleen, and accessory cells (>95% adherent, esterase-positive) were obtained by peritoneal lavage. Purified T cells or accessory cells from each diet group were co-cultured with the alternative cell type from every other diet group, yielding a total of 16 different co-culture combinations. The T cells were stimulated with either concanavalin A (ConA) or antibodies to the T cell receptor (TcR)/CD3 complex and the costimulatory molecule CD28 (αCD3/αCD28), and proliferation was measured after four days. Suppression of T cell proliferation in the co-cultures was dependent upon the dose of dietary n-3 PUFA fed to mice from which the T cells were derived, irrespective of the dietary treatment of accessory cell donors. The greatest dietary effect was seen in mice consuming the DHA diet (P = 0·034 in the anova; P = 0·0053 in the Trend Test), and was observed with direct stimulation of the T cell receptor and CD28 costimulatory ligand, but not with ConA. A significant dietary effect was also contributed accessory cells (P = 0·033 in the Trend Test). We conclude that dietary n-3 PUFA affect TcR-mediated by T cell activation by both direct and indirect (accessory cell) mechanisms. PMID:12296847

  10. Multifaceted effects of synthetic TLR2 ligand and Legionella pneumophilia on Treg-mediated suppression of T cell activation

    Directory of Open Access Journals (Sweden)

    Sutmuller Roger PM

    2011-03-01

    Full Text Available Abstract Background Regulatory T cells (Treg play a crucial role in maintaining immune homeostasis and self-tolerance. The immune suppressive effects of Tregs should however be limited in case effective immunity is required against pathogens or cancer cells. We previously found that the Toll-like receptor 2 (TLR2 agonist, Pam3CysSK4, directly stimulated Tregs to expand and temporarily abrogate their suppressive capabilities. In this study, we evaluate the effect of Pam3CysSK4 and Legionella pneumophila, a natural TLR2 containing infectious agent, on effector T (Teff cells and dendritic cells (DCs individually and in co-cultures with Tregs. Results TLR2 agonists can directly provide a co-stimulatory signal inducing enhanced proliferation and cytokine production of naive CD4+ Teff cells. With respect to cytokine production, DCs appear to be most sensitive to low amounts of TLR agonists. Using wild type and TLR2-deficient cells in Treg suppression assays, we accordingly show that all cells (e.g. Treg, Teff cells and DCs contributed to overcome Treg-mediated suppression of Teff cell proliferation. Furthermore, while TLR2-stimulated Tregs readily lost their ability to suppress Teff cell proliferation, cytokine production by Teff cells was still suppressed. Similar results were obtained upon stimulation with TLR2 ligand containing bacteria, Legionella pneumophila. Conclusions These findings indicate that both synthetic and natural TLR2 agonists affect DCs, Teff cells and Treg directly, resulting in multi-modal modulation of Treg-mediated suppression of Teff cells. Moreover, Treg-mediated suppression of Teff cell proliferation is functionally distinct from suppression of cytokine secretion.

  11. Heat shock protein 90-mediated peptide-selective presentation of cytosolic tumor antigen for direct recognition of tumors by CD4(+) T cells.

    Science.gov (United States)

    Tsuji, Takemasa; Matsuzaki, Junko; Caballero, Otavia L; Jungbluth, Achim A; Ritter, Gerd; Odunsi, Kunle; Old, Lloyd J; Gnjatic, Sacha

    2012-04-15

    Tumor Ag-specific CD4(+) T cells play important functions in tumor immunosurveillance, and in certain cases they can directly recognize HLA class II-expressing tumor cells. However, the underlying mechanism of intracellular Ag presentation to CD4(+) T cells by tumor cells has not yet been well characterized. We analyzed two naturally occurring human CD4(+) T cell lines specific for different peptides from cytosolic tumor Ag NY-ESO-1. Whereas both lines had the same HLA restriction and a similar ability to recognize exogenous NY-ESO-1 protein, only one CD4(+) T cell line recognized NY-ESO-1(+) HLA class II-expressing melanoma cells. Modulation of Ag processing in melanoma cells using specific molecular inhibitors and small interfering RNA revealed a previously undescribed peptide-selective Ag-presentation pathway by HLA class II(+) melanoma cells. The presentation required both proteasome and endosomal protease-dependent processing mechanisms, as well as cytosolic heat shock protein 90-mediated chaperoning. Such tumor-specific pathway of endogenous HLA class II Ag presentation is expected to play an important role in immunosurveillance or immunosuppression mediated by various subsets of CD4(+) T cells at the tumor local site. Furthermore, targeted activation of tumor-recognizing CD4(+) T cells by vaccination or adoptive transfer could be a suitable strategy for enhancing the efficacy of tumor immunotherapy.

  12. Chronic Inflammation and  T Cells

    Directory of Open Access Journals (Sweden)

    Nathan S Fay

    2016-05-01

    Full Text Available The epithelial tissues of the skin, lungs, reproductive tract, and intestines are the largest physical barriers the body has to protect against infection. Epithelial tissues are woven with a matrix of immune cells programmed to mobilize the host innate and adaptive immune responses. Included among these immune cells are  T cells that are unique in their TCR usage, location, and functions in the body. Stress reception by  T cells as a result of traumatic epithelial injury, malignancy, and/or infection induces  T cell activation. Once activated,  T cells function to repair tissue, induce inflammation, recruit leukocytes, and lyse cells. Many of these functions are mediated via the production of cytokines and growth factors upon  T cell activation. Pathogenesis of many chronic inflammatory diseases involve  T cells; some of which are exacerbated by their presence, while others are improved.  T cells require a delicate balance between their need for acute inflammatory mediators to function normally and the detrimental impact imparted by chronic inflammation. This review will focus on the recent progress made in understanding how epithelial  T cells influence the pathogenesis of chronic inflammatory diseases and how a balance between acute and chronic inflammation impacts  T cell function. Future studies will be important to understand how this balance is achieved.

  13. Gamma Delta T-Cells Regulate Inflammatory Cell Infiltration of the Lung after Trauma-Hemorrhage

    Science.gov (United States)

    2015-06-01

    suggesting a role for this T- cell subset in both innate and acquired immunity (7, 8). Studies have shown that +% T cells are required for both controlled...increased infiltration of both lymphoid and myeloid cells in WT mice after TH-induced ALI. In parallel to +% T cells , myeloid cells (i.e., monocytes...GAMMA DELTA T CELLS REGULATE INFLAMMATORY CELL INFILTRATION OF THE LUNG AFTER TRAUMA-HEMORRHAGE Meenakshi Rani,* Qiong Zhang,* Richard F. Oppeltz

  14. T cell-mediated hepatitis in mice infected with lymphocytic choriomeningitis virus. Liver cell destruction by H-2 class I-restricted virus-specific cytotoxic T cells as a physiological correlate of the 51Cr-release assay

    International Nuclear Information System (INIS)

    Zinkernagel, R.M.; Haenseler, E.; Leist, T.; Cerny, A.; Hengartner, H.; Althage, A.

    1986-01-01

    A model for immunologically T cell-mediated hepatitis was established in mice infected with lymphocytic choriomeningitis virus (LCMV). The severity of hepatitis was monitored histologically and by determination of changes in serum levels of the enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutamate dehydrogenase (GLDH), and alkaline phosphatase (AP). Kinetics of histological disease manifestations, increases of liver enzyme levels in the serum, and cytotoxic T cell activities in livers and spleens all correlated and were dependent upon several parameters: LCMV-isolate; LCMV-WE caused extensive hepatitis, LCMV-Armstrong virtually none. Virus dose. Route of infection; i.v. or i.p. infection caused hepatitis, whereas infection into the footpad did not. The general genetic background of the murine host; of the strains tested, Swiss mice and A-strain mice were more susceptible than C57BL or CBA mice; BALB/c and DBA/2 mice were least susceptible. The degree of immunocompetence of the murine host; T cell deficient nu/nu mice never developed hepatitis, whereas nu/+ or +/+ mice always did. B cell-depleted anti-IgM-treated mice developed immune-mediated hepatitis comparably or even more extensively than control mice. Local cytotoxic T cell activity; mononuclear cells isolated from livers during the period of overt hepatitis were two to five times more active than equal numbers of spleen cells. Adoptive transfer of nylon wool-nonadherent anti-Thy-1.2 and anti-Lyt-2 plus C-sensitive, anti-L3T4 plus C-resistant lymphocytes into irradiated mice preinfected with LCMV-WE caused a rapid time- and dose-dependent linear increase of serum enzyme levels. This increase was caused by adoptive transfer of lymphocytes if immune cell donors and recipient mice shared class I, but not when they shared class II histocompatibility antigens

  15. Activated integrin VLA-4 localizes to the lamellipodia and mediates T cell migration on VCAM-11

    Science.gov (United States)

    Hyun, Young-Min; Chung, Hung-Li; McGrath, James L.; Waugh, Richard E.; Kim, Minsoo

    2009-01-01

    Lymphocyte migration from blood into lymphoid tissues or to sites of inflammation occurs through interactions between cell surface integrins and their ligands expressed on the vascular endothelium and the extracellular matrix. Very Late Antigen-4 (VLA-4, α4β1) is a key integrin in the effective trafficking of lymphocytes. Although it has been well established that integrins undergo functionally significant conformational changes to mediate cell adhesion, there is no mechanistic information that explains how these are dynamically and spatially regulated during lymphocyte polarization and migration. Using dynamic fluorescence resonance energy transfer (FRET) analysis of a novel VLA-4 FRET sensor under total internal reflection fluorescence (TIRF) microscopy, we show that VLA-4 activation localizes to the lamellipodium in living cells. During T cell migration on VCAM-1, VLA-4 activation concurs with spatial redistribution of chemokine receptor and active Rap1 at the leading edge. Selective inhibition of the activated VLA-4 at leading edge with a small molecule inhibitor is sufficient to block T cell migration. These data suggest that a subpopulation of activated VLA-4 is mainly localized to the leading edge of polarized human T cells, and is critical for T cell migration on VCAM-1. PMID:19542447

  16. Cytokines affecting CD4+T regulatory cells in transplant tolerance. III. Interleukin-5 (IL-5) promotes survival of alloantigen-specific CD4+ T regulatory cells.

    Science.gov (United States)

    Hall, Bruce M; Plain, Karren M; Tran, Giang T; Verma, Nirupama D; Robinson, Catherine M; Nomura, Masaru; Boyd, Rochelle; Hodgkinson, Suzanne J

    2017-08-01

    CD4 + T cells mediate antigen-specific allograft tolerance, but die in culture without activated lymphocyte derived cytokines. Supplementation of the media with cytokine rich supernatant, from ConA activated spleen cells, preserves the capacity of tolerant cells to transfer tolerance and suppress rejection. rIL-2 or rIL-4 alone are insufficient to maintain these cells, however. We observed that activation of naïve CD4 + CD25 + FOXP3 + Treg with alloantigen and the Th2 cytokine rIL-4 induces them to express interleukin-5 specific receptor alpha (IL-5Rα) suggesting that IL-5, a Th2 cytokine that is produced later in the immune response may promote tolerance mediating Treg. This study examined if recombinant IL-5(rIL-5) promoted survival of tolerant CD4 + , especially CD4 + CD25 + T cells. CD4 + T cells, from DA rats tolerant to fully allogeneic PVG heart allografts surviving over 100days without on-going immunosuppression, were cultured with PVG alloantigen and rIL-5. The ability of these cells to adoptively transfer tolerance to specific-donor allograft and suppress normal CD4 + T cell mediated rejection in adoptive DA hosts was examined. Tolerant CD4 + CD25 + T cells' response to rIL-5 and expression of IL-5Rα was also assessed. rIL-5 was sufficient to promote transplant tolerance mediating CD4 + T cells' survival in culture with specific-donor alloantigen. Tolerant CD4 + T cells cultured with rIL-5 retained the capacity to transfer alloantigen-specific tolerance and inhibited naïve CD4 + T cells' capacity to effect specific-donor graft rejection. rIL-5 promoted tolerant CD4 + CD25 + T cells' proliferation in vitro when stimulated with specific-donor but not third-party stimulator cells. Tolerant CD4 + CD25 + T cells expressed IL-5Rα. This study demonstrated that IL-5 promoted the survival of alloantigen-specific CD4 + CD25 + T cells that mediate transplant tolerance. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Role of T cell receptor affinity in the efficacy and specificity of adoptive T cell therapies

    Directory of Open Access Journals (Sweden)

    Jennifer D. Stone

    2013-08-01

    Full Text Available Over the last several years, there has been considerable progress in the treatment of cancer using gene modified adoptive T cell therapies. Two approaches have been used, one involving the introduction of a conventional alpha-beta T cell receptor (TCR against a pepMHC cancer antigen, and the second involving introduction of a chimeric antigen receptor (CAR consisting of a single-chain antibody as an Fv fragment (scFv linked to transmembrane and signaling domains. In this review, we focus on one aspect of TCR-mediated adoptive T cell therapies, the impact of the affinity of the alpha-beta TCR for the pepMHC cancer antigen on both efficacy and specificity. We discuss the advantages of higher affinity TCRs in mediating potent activity of CD4 T cells. This is balanced with the potential disadvantage of higher affinity TCRs in mediating greater self-reactivity against a wider range of structurally similar antigenic peptides, especially in synergy with the CD8 co-receptor. Both TCR affinity and target selection will influence potential safety issues. We suggest pre-clinical strategies that might be used to examine each TCR for possible on-target and off-target side effects due to self-reactivities, and to adjust TCR affinities accordingly.

  18. The Tol2 transposon system mediates the genetic engineering of T-cells with CD19-specific chimeric antigen receptors for B-cell malignancies.

    Science.gov (United States)

    Tsukahara, T; Iwase, N; Kawakami, K; Iwasaki, M; Yamamoto, C; Ohmine, K; Uchibori, R; Teruya, T; Ido, H; Saga, Y; Urabe, M; Mizukami, H; Kume, A; Nakamura, M; Brentjens, R; Ozawa, K

    2015-02-01

    Engineered T-cell therapy using a CD19-specific chimeric antigen receptor (CD19-CAR) is a promising strategy for the treatment of advanced B-cell malignancies. Gene transfer of CARs to T-cells has widely relied on retroviral vectors, but transposon-based gene transfer has recently emerged as a suitable nonviral method to mediate stable transgene expression. The advantages of transposon vectors compared with viral vectors include their simplicity and cost-effectiveness. We used the Tol2 transposon system to stably transfer CD19-CAR into human T-cells. Normal human peripheral blood lymphocytes were co-nucleofected with the Tol2 transposon donor plasmid carrying CD19-CAR and the transposase expression plasmid and were selectively propagated on NIH3T3 cells expressing human CD19. Expanded CD3(+) T-cells with stable and high-level transgene expression (~95%) produced interferon-γ upon stimulation with CD19 and specifically lysed Raji cells, a CD19(+) human B-cell lymphoma cell line. Adoptive transfer of these T-cells suppressed tumor progression in Raji tumor-bearing Rag2(-/-)γc(-/-) immunodeficient mice compared with control mice. These results demonstrate that the Tol2 transposon system could be used to express CD19-CAR in genetically engineered T-cells for the treatment of refractory B-cell malignancies.

  19. Conventional CD4+ T cells present bacterial antigens to induce cytotoxic and memory CD8+ T cell responses.

    Science.gov (United States)

    Cruz-Adalia, Aránzazu; Ramirez-Santiago, Guillermo; Osuna-Pérez, Jesús; Torres-Torresano, Mónica; Zorita, Virgina; Martínez-Riaño, Ana; Boccasavia, Viola; Borroto, Aldo; Martínez Del Hoyo, Gloria; González-Granado, José María; Alarcón, Balbino; Sánchez-Madrid, Francisco; Veiga, Esteban

    2017-11-17

    Bacterial phagocytosis and antigen cross-presentation to activate CD8 + T cells are principal functions of professional antigen presenting cells. However, conventional CD4 + T cells also capture and kill bacteria from infected dendritic cells in a process termed transphagocytosis (also known as transinfection). Here, we show that transphagocytic T cells present bacterial antigens to naive CD8 + T cells, which proliferate and become cytotoxic in response. CD4 + T-cell-mediated antigen presentation also occurs in vivo in the course of infection, and induces the generation of central memory CD8 + T cells with low PD-1 expression. Moreover, transphagocytic CD4 + T cells induce protective anti-tumour immune responses by priming CD8 + T cells, highlighting the potential of CD4 + T cells as a tool for cancer immunotherapy.

  20. Gap junctions at the dendritic cell-T cell interface are key elements for antigen-dependent T cell activation.

    Science.gov (United States)

    Elgueta, Raul; Tobar, Jaime A; Shoji, Kenji F; De Calisto, Jaime; Kalergis, Alexis M; Bono, Maria R; Rosemblatt, Mario; Sáez, Juan C

    2009-07-01

    The acquired immune response begins with Ag presentation by dendritic cells (DCs) to naive T cells in a heterocellular cell-cell contact-dependent process. Although both DCs and T cells are known to express connexin43, a gap junction protein subunit, the role of connexin43 on the initiation of T cell responses remains to be elucidated. In the present work, we report the formation of gap junctions between DCs and T cells and their role on T cell activation during Ag presentation by DCs. In cocultures of DCs and T cells, Lucifer yellow microinjected into DCs is transferred to adjacent transgenic CD4(+) T cells, only if the specific antigenic peptide was present at least during the first 24 h of cocultures. This dye transfer was sensitive to gap junction blockers, such as oleamide, and small peptides containing the extracellular loop sequences of conexin. Furthermore, in this system, gap junction blockers drastically reduced T cell activation as reflected by lower proliferation, CD69 expression, and IL-2 secretion. This lower T cell activation produced by gap junction blockers was not due to a lower expression of CD80, CD86, CD40, and MHC-II on DCs. Furthermore, gap junction blocker did not affect polyclonal activation of T cell induced with anti-CD3 plus anti-CD28 Abs in the absence of DCs. These results strongly suggest that functional gap junctions assemble at the interface between DCs and T cells during Ag presentation and that they play an essential role in T cell activation.

  1. Nuclear Wiskott–Aldrich syndrome protein co-regulates T cell factor 1-mediated transcription in T cells

    Directory of Open Access Journals (Sweden)

    Nikolai V. Kuznetsov

    2017-10-01

    Full Text Available Abstract Background The Wiskott–Aldrich syndrome protein (WASp family of actin-nucleating factors are present in the cytoplasm and in the nucleus. The role of nuclear WASp for T cell development remains incompletely defined. Methods We performed WASp chromatin immunoprecipitation and deep sequencing (ChIP-seq in thymocytes and spleen CD4+ T cells. Results WASp was enriched at genic and intergenic regions and associated with the transcription start sites of protein-coding genes. Thymocytes and spleen CD4+ T cells showed 15 common WASp-interacting genes, including the gene encoding T cell factor (TCF12. WASp KO thymocytes had reduced nuclear TCF12 whereas thymocytes expressing constitutively active WASpL272P and WASpI296T had increased nuclear TCF12, suggesting that regulated WASp activity controlled nuclear TCF12. We identify a putative DNA element enriched in WASp ChIP-seq samples identical to a TCF1-binding site and we show that WASp directly interacted with TCF1 in the nucleus. Conclusions These data place nuclear WASp in proximity with TCF1 and TCF12, essential factors for T cell development.

  2. Nuclear pore complex-mediated modulation of TCR signaling is required for naïve CD4+ T cell homeostasis.

    Science.gov (United States)

    Borlido, Joana; Sakuma, Stephen; Raices, Marcela; Carrette, Florent; Tinoco, Roberto; Bradley, Linda M; D'Angelo, Maximiliano A

    2018-05-07

    Nuclear pore complexes (NPCs) are channels connecting the nucleus with the cytoplasm. We report that loss of the tissue-specific NPC component Nup210 causes a severe deficit of naïve CD4 + T cells. Nup210-deficient CD4 + T lymphocytes develop normally but fail to survive in the periphery. The decreased survival results from both an impaired ability to transmit tonic T cell receptor (TCR) signals and increased levels of Fas, which sensitize Nup210 -/- naïve CD4 + T cells to Fas-mediated cell death. Mechanistically, Nup210 regulates these processes by modulating the expression of Cav2 (encoding Caveolin-2) and Jun at the nuclear periphery. Whereas the TCR-dependent and CD4 + T cell-specific upregulation of Cav2 is critical for proximal TCR signaling, cJun expression is required for STAT3-dependent repression of Fas. Our results uncover an unexpected role for Nup210 as a cell-intrinsic regulator of TCR signaling and T cell homeostasis and expose NPCs as key players in the adaptive immune system.

  3. T-helper cell-mediated proliferation and cytokine responses against recombinant Merkel cell polyomavirus-like particles.

    Directory of Open Access Journals (Sweden)

    Arun Kumar

    Full Text Available The newly discovered Merkel Cell Polyomavirus (MCPyV resides in approximately 80% of Merkel cell carcinomas (MCC. Causal role of MCPyV for this rare and aggressive skin cancer is suggested by monoclonal integration and truncation of large T (LT viral antigen in MCC cells. The mutated MCPyV has recently been found in highly purified leukemic cells from patients with chronic lymphocytic leukemia (CLL, suggesting a pathogenic role also in CLL. About 50-80% of adults display MCPyV-specific antibodies. The humoral immunity does not protect against the development of MCC, as neutralizing MCPyV antibodies occur in higher levels among MCC patients than healthy controls. Impaired T-cell immunity has been linked with aggressive MCC behavior. Therefore, cellular immunity appears to be important in MCPyV infection surveillance. In order to elucidate the role of MCPyV-specific Th-cell immunity, peripheral blood mononuclear cells (PBMC of healthy adults were stimulated with MCPyV VP1 virus-like particles (VLPs, using human bocavirus (HBoV VLPs and Candida albicans antigen as positive controls. Proliferation, IFN-γ, IL-13 and IL-10 responses were examined in 15 MCPyV-seropositive and 15 seronegative volunteers. With the MCPyV antigen, significantly stronger Th-cell responses were found in MCPyV-seropositive than MCPyV-seronegative subjects, whereas with the control antigens, the responses were statistically similar. The most readily detectable cytokine was IFN-γ. The MCPyV antigen tended to induce stronger IFN-γ responses than HBoV VLP antigen. Taken together, MCPyV-specific Th-cells elicit vigorous IFN-γ responses. IFN-γ being a cytokine with major antiviral and tumor suppressing functions, Th-cells are suggested to be important mediators of MCPyV-specific immune surveillance.

  4. NF-κB functions as a molecular link between tumor cells and Th1/Tc1 T cells in the tumor microenvironment to exert radiation-mediated tumor suppression

    Science.gov (United States)

    Simon, Priscilla S.; Bardhan, Kankana; Chen, May R.; Paschall, Amy V.; Lu, Chunwan; Bollag, Roni J.; Kong, Feng-Chong; Jin, JianYue; Kong, Feng-Ming; Waller, Jennifer L.; Pollock, Raphael E.; Liu, Kebin

    2016-01-01

    Radiation modulates both tumor cells and immune cells in the tumor microenvironment to exert its anti-tumor activity; however, the molecular connection between tumor cells and immune cells that mediates radiation-exerted tumor suppression activity in the tumor microenvironment is largely unknown. We report here that radiation induces rapid activation of the p65/p50 and p50/p50 NF-κB complexes in human soft tissue sarcoma (STS) cells. Radiation-activated p65/p50 and p50/p50 bind to the TNFα promoter to activate its transcription in STS cells. Radiation-induced TNFα induces tumor cell death in an autocrine manner. A sublethal dose of Smac mimetic BV6 induces cIAP1 and cIAP2 degradation to increase tumor cell sensitivity to radiation-induced cell death in vitro and to enhance radiation-mediated suppression of STS xenografts in vivo. Inhibition of caspases, RIP1, or RIP3 blocks radiation/TNFα-induced cell death, whereas inhibition of RIP1 blocks TNFα-induced caspase activation, suggesting that caspases and RIP1 act sequentially to mediate the non-compensatory cell death pathways. Furthermore, we determined in a syngeneic sarcoma mouse model that radiation up-regulates IRF3, IFNβ, and the T cell chemokines CCL2 and CCL5 in the tumor microenvironment, which are associated with activation and increased infiltration of Th1/Tc1 T cells in the tumor microenvironment. Moreover, tumor-infiltrating T cells are in their active form since both the perforin and FasL pathways are activated in irradiated tumor tissues. Consequently, combined BV6 and radiation completely suppressed tumor growth in vivo. Therefore, radiation-induced NF-κB functions as a molecular link between tumor cells and immune cells in the tumor microenvironment for radiation-mediated tumor suppression. PMID:27014915

  5. T cell responses affected by aminopeptidase N (CD13)-mediated trimming of major histocompatibility complex class II-bound peptides

    DEFF Research Database (Denmark)

    Larsen, S L; Pedersen, L O; Buus, S

    1996-01-01

    Endocytosed protein antigens are believed to be fragmented in what appears to be a balance between proteolysis and MHC-mediated epitope protection, and the resulting peptide-MHC complexes are transported to the surface of the antigen-presenting cells (APC) and presented to T cells. The events tha...

  6. BCL11B is frequently downregulated in HTLV-1-infected T-cells through Tax-mediated proteasomal degradation.

    Science.gov (United States)

    Permatasari, Happy Kurnia; Nakahata, Shingo; Ichikawa, Tomonaga; Morishita, Kazuhiro

    2017-08-26

    Human T-cell leukemia virus type 1 (HTLV-1) is a causative agent of adult T-cell leukemia-lymphoma (ATLL). The HTLV-1-encoded protein Tax plays important roles in the proliferation of HTLV-1-infected T-cells by affecting cellular proteins. In this study, we showed that Tax transcriptionally and post-transcriptionally downregulates the expression of the tumor suppressor gene B-cell leukemia/lymphoma 11B (BCL11B), which encodes a lymphoid-related transcription factor. BCL11B expression was downregulated in HTLV-1-infected T-cell lines at the mRNA and protein levels, and forced expression of BCL11B suppressed the proliferation of these cells. The proteasomal inhibitor MG132 increased BCL11B expression in HTLV-1-infected cell lines, and colocalization of Tax with BCL11B was detected in the cytoplasm of HTLV-1-infected T-cells following MG132 treatment. shRNA knock-down of Tax expression also increased the expression of BCL11B in HTLV-1-infected cells. Moreover, we found that Tax physically binds to BCL11B protein and induces the polyubiquitination of BCL11B and proteasome-dependent degradation of BCL11B. Thus, inactivation of BCL11B by Tax protein may play an important role in the Tax-mediated leukemogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Suppression of pro-inflammatory T-cell responses by human mesothelial cells.

    Science.gov (United States)

    Lin, Chan-Yu; Kift-Morgan, Ann; Moser, Bernhard; Topley, Nicholas; Eberl, Matthias

    2013-07-01

    Human γδ T cells reactive to the microbial metabolite (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMB-PP) contribute to acute inflammatory responses. We have previously shown that peritoneal dialysis (PD)-associated infections with HMB-PP producing bacteria are characterized by locally elevated γδ T-cell frequencies and poorer clinical outcome compared with HMB-PP negative infections, implying that γδ T cells may be of diagnostic, prognostic and therapeutic value in acute disease. The regulation by local tissue cells of these potentially detrimental γδ T-cell responses remains to be investigated. Freshly isolated γδ or αβ T cells were cultured with primary mesothelial cells derived from omental tissue, or with mesothelial cell-conditioned medium. Stimulation of cytokine production and proliferation by peripheral T cells in response to HMB-PP or CD3/CD28 beads was assessed by flow cytometry. Resting mesothelial cells were potent suppressors of pro-inflammatory γδ T cells as well as CD4+ and CD8+ αβ T cells. The suppression of γδ T-cell responses was mediated through soluble factors released by primary mesothelial cells and could be counteracted by SB-431542, a selective inhibitor of TGF-β and activin signalling. Recombinant TGF-β1 but not activin-A mimicked the mesothelial cell-mediated suppression of γδ T-cell responses to HMB-PP. The present findings indicate an important regulatory function of mesothelial cells in the peritoneal cavity by dampening pro-inflammatory T-cell responses, which may help preserve the tissue integrity of the peritoneal membrane in the steady state and possibly during the resolution of acute inflammation.

  8. Role of T-bet, the master regulator of Th1 cells, in the cytotoxicity of murine CD4+ T cells.

    Science.gov (United States)

    Eshima, Koji; Misawa, Kana; Ohashi, Chihiro; Iwabuchi, Kazuya

    2018-05-01

    Although CD4 + T cells are generally regarded as helper T cells, some activated CD4 + T cells have cytotoxic properties. Given that CD4 + cytotoxic T lymphocytes (CTLs) often secrete IFN-γ, CTL activity among CD4 + T cells may be attributable to Th1 cells, where a T-box family molecule, T-bet serves as the "master regulator". However, although the essential contribution of T-bet to expression of IFN-γ has been well-documented, it remains unclear whether T-bet is involved in CD4 + T cell-mediated cytotoxicity. In this study, to investigate the ability of T-bet to confer cytolytic activity on CD4 + T cells, the T-bet gene (Tbx21) was introduced into non-cytocidal CD4 + T cell lines and their cytolytic function analyzed. Up-regulation of FasL (CD178), which provided the transfectant with cytotoxicity, was observed in Tbx21transfected CD4 + T cells but not in untransfected parental cells. In one cell line, T-bet transduction also induced perforin gene (Prf1) expression and Tbx21 transfectants efficiently killed Fas - target cells. Although T-bet was found to repress up-regulation of CD40L (CD154), which controls FasL-mediated cytolysis, the extent of CD40L up-regulation on in vitro-differentiated Th1 cells was similar to that on Th2 cells, suggesting the existence of a compensatory mechanism. These results collectively indicate that T-bet may be involved in the expression of genes, such as FasL and Prf1, which confer cytotoxicity on Th1 cells. © 2018 The Societies and John Wiley & Sons Australia, Ltd.

  9. Multiple injections of electroporated autologous T cells expressing a chimeric antigen receptor mediate regression of human disseminated tumor.

    Science.gov (United States)

    Zhao, Yangbing; Moon, Edmund; Carpenito, Carmine; Paulos, Chrystal M; Liu, Xiaojun; Brennan, Andrea L; Chew, Anne; Carroll, Richard G; Scholler, John; Levine, Bruce L; Albelda, Steven M; June, Carl H

    2010-11-15

    Redirecting T lymphocyte antigen specificity by gene transfer can provide large numbers of tumor-reactive T lymphocytes for adoptive immunotherapy. However, safety concerns associated with viral vector production have limited clinical application of T cells expressing chimeric antigen receptors (CAR). T lymphocytes can be gene modified by RNA electroporation without integration-associated safety concerns. To establish a safe platform for adoptive immunotherapy, we first optimized the vector backbone for RNA in vitro transcription to achieve high-level transgene expression. CAR expression and function of RNA-electroporated T cells could be detected up to a week after electroporation. Multiple injections of RNA CAR-electroporated T cells mediated regression of large vascularized flank mesothelioma tumors in NOD/scid/γc(-/-) mice. Dramatic tumor reduction also occurred when the preexisting intraperitoneal human-derived tumors, which had been growing in vivo for >50 days, were treated by multiple injections of autologous human T cells electroporated with anti-mesothelin CAR mRNA. This is the first report using matched patient tumor and lymphocytes showing that autologous T cells from cancer patients can be engineered to provide an effective therapy for a disseminated tumor in a robust preclinical model. Multiple injections of RNA-engineered T cells are a novel approach for adoptive cell transfer, providing flexible platform for the treatment of cancer that may complement the use of retroviral and lentiviral engineered T cells. This approach may increase the therapeutic index of T cells engineered to express powerful activation domains without the associated safety concerns of integrating viral vectors. Copyright © 2010 AACR.

  10. A proteomic view at T cell costimulation.

    Directory of Open Access Journals (Sweden)

    Rudolf Lichtenfels

    Full Text Available The "two-signal paradigm" in T cell activation predicts that the cooperation of "signal 1," provided by the T cell receptor (TCR through engagement of major histocompatility complex (MHC-presented peptide, with "signal 2″ provided by costimulatory molecules, the prototype of which is CD28, is required to induce T cell effector functions. While the individual signalling pathways are well understood, little is known about global changes in the proteome pattern during TCR/CD28-mediated activation. Therefore, comparative 2-DE-based proteome analyses of CD3(+ CD69(- resting T cells versus cells incubated with (i the agonistic anti-CD3 antibody OKT3 mimicking signal 1 in absence or presence of IL-2 and/or with (ii the agonistic antibody 15E8 triggering CD28-mediated signaling were performed. Differentially regulated spots were defined leading to the identification of proteins involved in the regulation of the metabolism, shaping and maintenance of the cytoskeleton and signal transduction. Representative members of the differentially expressed protein families, such as calmodulin (CALM, glyceraldehyde-3-phosphate dehydrogenase (GAPDH, L-lactate dehydrogenase (LDH, Rho GDP-dissociation inhibitor 2 (GDIR2, and platelet basic protein (CXCL7, were independently verified by flow cytometry. Data provide a detailed map of individual protein alterations at the global proteome level in response to TCR/CD28-mediated T cell activation.

  11. Glutathione-mediated detoxification of halobenzoquinone drinking water disinfection byproducts in T24 cells.

    Science.gov (United States)

    Li, Jinhua; Wang, Wei; Zhang, Hongquan; Le, X Chris; Li, Xing-Fang

    2014-10-01

    Halobenzoquinones (HBQs) are a new class of drinking water disinfection byproducts (DBPs) and are capable of producing reactive oxygen species and causing oxidative damage to proteins and DNA in T24 human bladder carcinoma cells. However, the exact mechanism of the cytotoxicity of HBQs is unknown. Here, we investigated the role of glutathione (GSH) and GSH-related enzymes including glutathione S-transferase (GST) and glutathione peroxidase (GPx) in defense against HBQ-induced cytotoxicity in T24 cells. The HBQs are 2,6-dichloro-1,4-benzoquinone (DCBQ), 2,6-dichloro-3-methyl-1,4-benzoquinone (DCMBQ), 2,3,6-trichloro-1,4-benzoquinone (TriCBQ), and 2,6-dibromobenzoquinone (DBBQ). We found that depletion of cellular GSH could sensitize cells to HBQs and extracellular GSH supplementation could attenuate HBQ-induced cytotoxicity. HBQs caused significant cellular GSH depletion and increased cellular GST activities in a concentration-dependent manner. Our mass spectrometry study confirms that HBQs can conjugate with GSH, explaining in part the mechanism of GSH depletion by HBQs. The effects of HBQs on GPx activity are compound dependent; DCMBQ and DBBQ decrease cellular GPx activities, whereas DCBQ and TriCBQ have no significant effects. Pearson correlation analysis shows that the cellular GSH level is inversely correlated with ROS production and cellular GST activity in HBQ-treated cells. These results support a GSH and GSH-related enzyme-mediated detoxification mechanism of HBQs in T24 cells. © The Author 2014. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  12. Glioblastoma-targeted CD4+ CAR T cells mediate superior antitumor activity.

    Science.gov (United States)

    Wang, Dongrui; Aguilar, Brenda; Starr, Renate; Alizadeh, Darya; Brito, Alfonso; Sarkissian, Aniee; Ostberg, Julie R; Forman, Stephen J; Brown, Christine E

    2018-05-17

    Chimeric antigen receptor-modified (CAR-modified) T cells have shown promising therapeutic effects for hematological malignancies, yet limited and inconsistent efficacy against solid tumors. The refinement of CAR therapy requires an understanding of the optimal characteristics of the cellular products, including the appropriate composition of CD4+ and CD8+ subsets. Here, we investigated the differential antitumor effect of CD4+ and CD8+ CAR T cells targeting glioblastoma-associated (GBM-associated) antigen IL-13 receptor α2 (IL13Rα2). Upon stimulation with IL13Rα2+ GBM cells, the CD8+ CAR T cells exhibited robust short-term effector function but became rapidly exhausted. By comparison, the CD4+ CAR T cells persisted after tumor challenge and sustained their effector potency. Mixing with CD4+ CAR T cells failed to ameliorate the effector dysfunction of CD8+ CAR T cells, while surprisingly, CD4+ CAR T cell effector potency was impaired when coapplied with CD8+ T cells. In orthotopic GBM models, CD4+ outperformed CD8+ CAR T cells, especially for long-term antitumor response. Further, maintenance of the CD4+ subset was positively correlated with the recursive killing ability of CAR T cell products derived from GBM patients. These findings identify CD4+ CAR T cells as a highly potent and clinically important T cell subset for effective CAR therapy.

  13. Inefficient Nef-mediated downmodulation of CD3 and MHC-I correlates with loss of CD4+T cells in natural SIV infection.

    Directory of Open Access Journals (Sweden)

    Michael Schindler

    2008-07-01

    Full Text Available Recent data suggest that Nef-mediated downmodulation of TCR-CD3 may protect SIVsmm-infected sooty mangabeys (SMs against the loss of CD4+ T cells. However, the mechanisms underlying this protective effect remain unclear. To further assess the role of Nef in nonpathogenic SIV infection, we cloned nef alleles from 11 SIVsmm-infected SMs with high (>500 and 15 animals with low (<500 CD4+ T-cells/microl in bulk into proviral HIV-1 IRES/eGFP constructs and analyzed their effects on the phenotype, activation, and apoptosis of primary T cells. We found that not only efficient Nef-mediated downmodulation of TCR-CD3 but also of MHC-I correlated with preserved CD4+ T cell counts, as well as with high numbers of Ki67+CD4+ and CD8+CD28+ T cells and reduced CD95 expression by CD4+ T cells. Moreover, effective MHC-I downregulation correlated with low proportions of effector and high percentages of naïve and memory CD8+ T cells. We found that T cells infected with viruses expressing Nef alleles from the CD4low SM group expressed significantly higher levels of the CD69, interleukin (IL-2 and programmed death (PD-1 receptors than those expressing Nefs from the CD4high group. SIVsmm Nef alleles that were less active in downmodulating TCR-CD3 were also less potent in suppressing the activation of virally infected T cells and subsequent cell death. However, only nef alleles from a single animal with very low CD4+ T cell counts rendered T cells hyper-responsive to activation, similar to those of HIV-1. Our data suggest that Nef may protect the natural hosts of SIV against the loss of CD4+ T cells by at least two mechanisms: (i downmodulation of TCR-CD3 to prevent activation-induced cell death and to suppress the induction of PD-1 that may impair T cell function and survival, and (ii downmodulation of MHC-I to reduce CTL lysis of virally infected CD4+ T cells and/or bystander CD8+ T cell activation.

  14. Human retinal pigment epithelial cell-induced apoptosis in activated T cells

    DEFF Research Database (Denmark)

    Jørgensen, A; Wiencke, A K; la Cour, M

    1998-01-01

    human retinal pigment epithelial (RPE) cells can induce apoptosis in activated T cells. METHODS: Fas ligand (FasL) expression was detected by flow cytometry and immunohistochemistry. Cultured RPE cells were cocultured with T-cell lines and peripheral blood lymphocytes for 6 hours to 2 days. Induction...... of apoptosis was detected by 7-amino-actinomycin D and annexin V staining. RESULTS: Retinal pigment epithelial cells expressed FasL and induced apoptosis in activated Fas+ T cells. Blocking of Fas-FasL interaction with antibody strongly inhibited RPE-mediated T-cell apoptosis. Retinal pigment epithelial cells...... induced apoptosis in several activated T-cell populations and T-cell lines, including T-cell antigen receptor (TCR)-CD3-negative T-cell lines. In contrast, RPE cells induced little or no apoptosis in resting peripheral T cells. Major histocompatibility complex (MHC) class II monoclonal antibodies, which...

  15. TNFRSF14 aberrations in follicular lymphoma increase clinically significant allogeneic T-cell responses.

    Science.gov (United States)

    Kotsiou, Eleni; Okosun, Jessica; Besley, Caroline; Iqbal, Sameena; Matthews, Janet; Fitzgibbon, Jude; Gribben, John G; Davies, Jeffrey K

    2016-07-07

    Donor T-cell immune responses can eradicate lymphomas after allogeneic hematopoietic stem cell transplantation (AHSCT), but can also damage healthy tissues resulting in harmful graft-versus-host disease (GVHD). Next-generation sequencing has recently identified many new genetic lesions in follicular lymphoma (FL). One such gene, tumor necrosis factor receptor superfamily 14 (TNFRSF14), abnormal in 40% of FL patients, encodes the herpes virus entry mediator (HVEM) which limits T-cell activation via ligation of the B- and T-lymphocyte attenuator. As lymphoma B cells can act as antigen-presenting cells, we hypothesized that TNFRSF14 aberrations that reduce HVEM expression could alter the capacity of FL B cells to stimulate allogeneic T-cell responses and impact the outcome of AHSCT. In an in vitro model of alloreactivity, human lymphoma B cells with TNFRSF14 aberrations had reduced HVEM expression and greater alloantigen-presenting capacity than wild-type lymphoma B cells. The increased immune-stimulatory capacity of lymphoma B cells with TNFRSF14 aberrations had clinical relevance, associating with higher incidence of acute GVHD in patients undergoing AHSCT. FL patients with TNFRSF14 aberrations may benefit from more aggressive immunosuppression to reduce harmful GVHD after transplantation. Importantly, this study is the first to demonstrate the impact of an acquired genetic lesion on the capacity of tumor cells to stimulate allogeneic T-cell immune responses which may have wider consequences for adoptive immunotherapy strategies. © 2016 by The American Society of Hematology.

  16. Induction of CD4 suppressor T cells with anti-Leu-8 antibody

    International Nuclear Information System (INIS)

    Kanof, M.E.; Strober, W.; James, S.P.

    1987-01-01

    To characterize the conditions under which CD4 T cells suppress polyclonal immunoglobulin synthesis, we investigated the capacity of CD4 T cells that coexpress the surface antigen recognized by the monoclonal antibody anti-Leu-8 to mediate suppression. In an in vitro system devoid of CD8 T cells, CD4, Leu-8+ T cells suppressed pokeweed mitogen-induced immunoglobulin synthesis. Similarly, suppressor function was induced in unfractionated CD4 T cell populations after incubation with anti-Leu-8 antibody under cross-linking conditions. This induction of suppressor function by anti-Leu-8 antibody was not due to expansion of the CD4, Leu-8+ T cell population because CD4 T cells did not proliferate in response to anti-Leu-8 antibody. However, CD4, Leu-8+ T cell-mediated suppression was radiosensitive. Finally, CD4, Leu-8+ T cells do not inhibit immunoglobulin synthesis when T cell lymphokines were used in place of helper CD4 T cells (CD4, Leu-8- T cells), suggesting that CD4 T cell-mediated suppression occurs at the T cell level. We conclude that CD4 T cells can be induced to suppress immunoglobulin synthesis by modulation of the membrane antigen recognized by anti-Leu-8 antibody

  17. T-cell libraries allow simple parallel generation of multiple peptide-specific human T-cell clones.

    Science.gov (United States)

    Theaker, Sarah M; Rius, Cristina; Greenshields-Watson, Alexander; Lloyd, Angharad; Trimby, Andrew; Fuller, Anna; Miles, John J; Cole, David K; Peakman, Mark; Sewell, Andrew K; Dolton, Garry

    2016-03-01

    Isolation of peptide-specific T-cell clones is highly desirable for determining the role of T-cells in human disease, as well as for the development of therapies and diagnostics. However, generation of monoclonal T-cells with the required specificity is challenging and time-consuming. Here we describe a library-based strategy for the simple parallel detection and isolation of multiple peptide-specific human T-cell clones from CD8(+) or CD4(+) polyclonal T-cell populations. T-cells were first amplified by CD3/CD28 microbeads in a 96U-well library format, prior to screening for desired peptide recognition. T-cells from peptide-reactive wells were then subjected to cytokine-mediated enrichment followed by single-cell cloning, with the entire process from sample to validated clone taking as little as 6 weeks. Overall, T-cell libraries represent an efficient and relatively rapid tool for the generation of peptide-specific T-cell clones, with applications shown here in infectious disease (Epstein-Barr virus, influenza A, and Ebola virus), autoimmunity (type 1 diabetes) and cancer. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  18. Phenotypic and functional characterization of human memory T cell responses to Burkholderia pseudomallei.

    Directory of Open Access Journals (Sweden)

    Patcharaporn Tippayawat

    Full Text Available Infection with the Gram-negative bacterium Burkholderia pseudomallei is an important cause of community-acquired lethal sepsis in endemic regions in southeast Asia and northern Australia and is increasingly reported in other tropical areas. In animal models, production of interferon-gamma (IFN-gamma is critical for resistance, but in humans the characteristics of IFN-gamma production and the bacterial antigens that are recognized by the cell-mediated immune response have not been defined.Peripheral blood from 133 healthy individuals who lived in the endemic area and had no history of melioidosis, 60 patients who had recovered from melioidosis, and 31 other patient control subjects were stimulated by whole bacteria or purified bacterial proteins in vitro, and IFN-gamma responses were analyzed by ELISPOT and flow cytometry.B. pseudomallei was a potent activator of human peripheral blood NK cells for innate production of IFN-gamma. In addition, healthy individuals with serological evidence of exposure to B. pseudomallei and patients recovered from active melioidosis developed CD4(+ (and CD8(+ T cells that recognized whole bacteria and purified proteins LolC, OppA, and PotF, members of the B. pseudomallei ABC transporter family. This response was primarily mediated by terminally differentiated T cells of the effector-memory (T(EMRA phenotype and correlated with the titer of anti-B. pseudomallei antibodies in the serum.Individuals living in a melioidosis-endemic region show clear evidence of T cell priming for the ability to make IFN-gamma that correlates with their serological status. The ability to detect T cell responses to defined B. pseudomallei proteins in large numbers of individuals now provides the opportunity to screen candidate antigens for inclusion in protein or polysaccharide-conjugate subunit vaccines against this important but neglected disease.

  19. Heterosybtypic T-cell immunity to influenza in humans: challenges for universal T-cell influenza vaccines

    Directory of Open Access Journals (Sweden)

    Saranya eSridhar

    2016-05-01

    Full Text Available Influenza A virus (IAV remains a significant global health issue causing annual epidemics, pandemics and sporadic human infections with highly pathogenic avian or swine influenza viruses. Current inactivated and live vaccines are the mainstay of the public health response to influenza although vaccine efficacy is lower against antigenically distinct viral strains. The first pandemic of the 21st century underlined the urgent need to develop new vaccines capable of protection against a broad range of influenza strains. Such universal influenza vaccines are based on the idea of heterosubtypic immunity wherein immune responses to epitopes conserved across IAV strains can confer protection against subsequent infection and disease. T-cells recognising conserved antigens are a key contributor to reducing viral load and limiting disease severity during heterosubtypic infection in animal models. Recent studies undertaken during the 2009 H1N1 pandemic provided key insights into the role of cross-reactive T-cells in mediating heterosubtypic protection in humans. This review focuses on human influenza to discuss the epidemiological observations that underpin cross-protective immunity, the role of T-cells as key players in mediating heterosubtypic immunity including recent data from natural history cohort studies and the ongoing clinical development of T-cell inducing universal influenza vaccines. The challenges and knowledge gaps for developing vaccines to generate long-lived protective T-cell responses is discussed.

  20. Tumor-associated mesenchymal stem cells inhibit naïve T cell expansion by blocking cysteine export from dendritic cells.

    Science.gov (United States)

    Ghosh, Tithi; Barik, Subhasis; Bhuniya, Avishek; Dhar, Jesmita; Dasgupta, Shayani; Ghosh, Sarbari; Sarkar, Madhurima; Guha, Ipsita; Sarkar, Koustav; Chakrabarti, Pinak; Saha, Bhaskar; Storkus, Walter J; Baral, Rathindranath; Bose, Anamika

    2016-11-01

    Mesenchymal stem cells (MSCs) represent an important cellular constituent of the tumor microenvironment, which along with tumor cells themselves, serve to regulate protective immune responses in support of progressive disease. We report that tumor MSCs prevent the ability of dendritic cells (DC) to promote naïve CD4(+) and CD8(+) T cell expansion, interferon gamma secretion and cytotoxicity against tumor cells, which are critical to immune-mediated tumor eradication. Notably, tumor MSCs fail to prevent DC-mediated early T cell activation events or the ability of responder T cells to produce IL-2. The immunoregulatory activity of tumor MSCs is IL-10- and STAT3-dependent, with STAT3 repressing DC expression of cystathionase, a critical enzyme that converts methionine-to-cysteine. Under cysteine-deficient priming conditions, naïve T cells exhibit defective cellular metabolism and proliferation. Bioinformatics analyses as well as in vitro observations suggest that STAT3 may directly bind to a GAS-like motif within the cystathionase promoter (-269 to -261) leading to IL-10-STAT3 mediated repression of cystathionase gene transcription. Our collective results provide evidence for a novel mechanism of tumor MSC-mediated T cell inhibition within tumor microenvironment. © 2016 UICC.

  1. Regulation of CD95 expression and CD95-mediated cell death by interferon-gamma in acute lymphoblastic leukemia with chromosomal translocation t(4;11).

    Science.gov (United States)

    Dörrie, J; Schuh, W; Keil, A; Bongards, E; Greil, J; Fey, G H; Zunino, S J

    1999-10-01

    The regulatory effects of IFNgamma on CD95 expression and CD95-mediated cell death were investigated in three high-risk pro-B acute lymphoblastic leukemia (ALL) lines that carry the chromosomal translocation t(4;11)(q21;q23). These leukemias are characteristically refractory to conventional chemotherapeutic treatments operating through the induction of apoptosis. However, the mechanisms leading to increased cell survival and resistance to cell death in these leukemias are largely unknown. Interferon-gamma (IFNgamma), a potent inhibitor of hematopoiesis, acts in part by upregulating CD95 and sensitizing cells to CD95-induced apoptosis. The t(4;11) lines SEM, RS4;11, and MV4;11 expressed low levels of CD95, but were completely resistant to CD95-mediated death. Addition of IFNgamma markedly upregulated CD95 expression in SEM (8-9-fold), RS4;11 (2-3-fold), and MV4;11 (2-3-fold) lines. However, after treatment with IFNgamma, only an 11% increase in sensitivity to CD95-mediated cell death was observed in SEM cells, whereas RS4;11 and MV4;11 cells remained resistant. Cycloheximide, but not actinomycin D or brefeldin A, increased CD95-specific cell death only in IFNgamma-treated RS4;11 cells by approximately 12%. Abundant levels of Bcl-2 and Bcl-XL, known to inhibit CD95-signaling in some cells, were present suggesting a possible role for both molecules in the resistance to CD95-mediated cell death. Resistance of the leukemic blasts to CD95-mediated cell death and the failure of IFNgamma to substantially sensitize the CD95-signaling pathway may contribute to the highly malignant phenotype of pro-B ALL with translocation t(4;11).

  2. Green tea EGCG, T-cell function, and T-cell-mediated autoimmune encephalomyelitis

    Science.gov (United States)

    Autoimmune diseases are common, disabling immune disorders affecting millions of people. Recent studies indicate that dysregulated balance of different CD4+ T-cell subpopulations plays a key role in immune pathogenesis of several major autoimmune diseases. Green tea and its active ingredient, epigal...

  3. Inducible nitric-oxide synthase plays a minimal role in lymphocytic choriomeningitis virus-induced, T cell-mediated protective immunity and immunopathology

    DEFF Research Database (Denmark)

    Bartholdy, C; Nansen, A; Christensen, Jeanette Erbo

    1999-01-01

    -mediated immune response was found to be unaltered in iNOS-deficient mice compared with wild-type C57BL/6 mice, and LCMV- induced general immunosuppression was equally pronounced in both strains. In vivo analysis revealed identical kinetics of virus clearance, as well as unaltered clinical severity of systemic......By using mice with a targetted disruption in the gene encoding inducible nitric-oxide synthase (iNOS), we have studied the role of nitric oxide (NO) in lymphocytic choriomeningitis virus (LCMV)-induced, T cell-mediated protective immunity and immunopathology. The afferent phase of the T cell...... LCMV infection in both strains. Concerning the outcome of intracerebral infection, no significant differences were found between iNOS-deficient and wild-type mice in the number or composition of mononuclear cells found in the cerebrospinal fluid on day 6 post-infection. Likewise, NO did not influence...

  4. Primary murine CD4+ T cells fail to acquire the ability to produce effector cytokines when active Ras is present during Th1/Th2 differentiation.

    Directory of Open Access Journals (Sweden)

    Sujit V Janardhan

    Full Text Available Constitutive Ras signaling has been shown to augment IL-2 production, reverse anergy, and functionally replace many aspects of CD28 co-stimulation in CD4+ T cells. These data raise the possibility that introduction of active Ras into primary T cells might result in improved functionality in pathologic situations of T cell dysfunction, such as cancer or chronic viral infection. To test the biologic effects of active Ras in primary T cells, CD4+ T cells from Coxsackie-Adenovirus Receptor Transgenic mice were transduced with an adenovirus encoding active Ras. As expected, active Ras augmented IL-2 production in naive CD4+ T cells. However, when cells were cultured for 4 days under conditions to promote effector cell differentiation, active Ras inhibited the ability of CD4+ T cells to acquire a Th1 or Th2 effector cytokine profile. This differentiation defect was not due to deficient STAT4 or STAT6 activation by IL-12 or IL-4, respectively, nor was it associated with deficient induction of T-bet and GATA-3 expression. Impaired effector cytokine production in active Ras-transduced cells was associated with deficient demethylation of the IL-4 gene locus. Our results indicate that, despite augmenting acute activation of naïve T cells, constitutive Ras signaling inhibits the ability of CD4+ T cells to properly differentiate into Th1/Th2 effector cytokine-producing cells, in part by interfering with epigenetic modification of effector gene loci. Alternative strategies to potentiate Ras pathway signaling in T cells in a more regulated fashion should be considered as a therapeutic approach to improve immune responses in vivo.

  5. Quantitative proteomics and transcriptomics addressing the estrogen receptor subtype-mediated effects in T47D breast cancer cells exposed to the phytoestrogen genistein

    NARCIS (Netherlands)

    Sotoca Covaleda, A.M.; Sollewijn Gelpke, M.D.; Boeren, S.; Ström, A.; Gustafsson, J.A.; Murk, A.J.; Rietjens, I.M.C.M.; Vervoort, J.J.M.

    2011-01-01

    The present study addresses, by transcriptomics and quantitative SILAC-based proteomics, the estrogen receptor alpha (ER) and beta (ERß)-mediated effects on gene and protein expression in T47D breast cancer cells exposed to the phytoestrogen genistein. Using the T47D human breast cancer cell line

  6. GADS is required for TCR-mediated calcium influx and cytokine release, but not cellular adhesion, in human T cells.

    Science.gov (United States)

    Bilal, Mahmood Y; Zhang, Elizabeth Y; Dinkel, Brittney; Hardy, Daimon; Yankee, Thomas M; Houtman, Jon C D

    2015-04-01

    GRB2 related adaptor protein downstream of Shc (GADS) is a member of the GRB2 family of adaptors and is critical for TCR-induced signaling. The current model is that GADS recruits SLP-76 to the LAT complex, which facilitates the phosphorylation of SLP-76, the activation of PLC-γ1, T cell adhesion and cytokine production. However, this model is largely based on studies of disruption of the GADS/SLP-76 interaction and murine T cell differentiation in GADS deficient mice. The role of GADS in mediating TCR-induced signals in human CD4+ T cells has not been thoroughly investigated. In this study, we have suppressed the expression of GADS in human CD4+ HuT78 T cells. GADS deficient HuT78 T cells displayed similar levels of TCR-induced SLP-76 and PLC-γ1 phosphorylation but exhibited substantial decrease in TCR-induced IL-2 and IFN-γ release. The defect in cytokine production occurred because of impaired calcium mobilization due to reduced recruitment of SLP-76 and PLC-γ1 to the LAT complex. Surprisingly, both GADS deficient HuT78 and GADS deficient primary murine CD8+ T cells had similar TCR-induced adhesion when compared to control T cells. Overall, our results show that GADS is required for calcium influx and cytokine production, but not cellular adhesion, in human CD4+ T cells, suggesting that the current model for T cell regulation by GADS is incomplete. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Direct evidence for a chronic CD8+-T-cell-mediated immune reaction to tax within the muscle of a human T-cell leukemia/lymphoma virus type 1-infected patient with sporadic inclusion body myositis.

    Science.gov (United States)

    Ozden, Simona; Cochet, Madeleine; Mikol, Jacqueline; Teixeira, Antonio; Gessain, Antoine; Pique, Claudine

    2004-10-01

    Human T-cell leukemia/lymphoma virus type 1 (HTLV-1) infection can lead to the development of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), concomitantly with or without other inflammatory disorders such as myositis. These pathologies are considered immune-mediated diseases, and it is assumed that migration within tissues of both HTLV-1-infected CD4(+) T cells and anti-HTLV-1 cytotoxic T cells represents a pivotal event. However, although HTLV-1-infected T cells were found in inflamed lesions, the antigenic specificity of coinfiltrated CD8(+) T cells remains to be determined. In this study, we performed both ex vivo and in situ analyses using muscle biopsies obtained from an HTLV-1-infected patient with HAM/TSP and sporadic inclusion body myositis. We found that both HTLV-1-infected CD4(+) T cells and CD8(+) T cells directed to the dominant Tax antigen can be amplified from muscle cell cultures. Moreover, we were able to detect in two successive muscle biopsies both tax mRNA-positive mononuclear cells and T cells recognized by the Tax11-19/HLA-A*02 tetramer and positive for perforin. These findings provide the first direct demonstration that anti-Tax cytotoxic T cells are chronically recruited within inflamed tissues of an HTLV-1 infected patient, which validates the cytotoxic immune reaction model for the pathogenesis of HTLV-1-associated inflammatory disease.

  8. Pregnancy promotes tolerance to future offspring by programming selective dysfunction in long-lived maternal T cells.

    Science.gov (United States)

    Barton, Brendan M; Xu, Rong; Wherry, E John; Porrett, Paige M

    2017-04-01

    Fetal antigen available during pregnancy induces the proliferation of maternal T cells. It is unknown, however, whether these antigen-activated T cells differentiate into long-lived memory T cells that are capable of mediating rapid-recall responses to tissue antigens. To test the hypothesis that pregnancy induces an alternative fate in fetal-specific maternal T cells, we used a murine model to track longitudinally fetal-specific T cells in pregnant and postpartum animals and test the response of these cells when challenged with the same antigen during sequential pregnancy or skin transplantation. Fetal-specific CD8 + T cells were robustly primed during pregnancy but failed to acquire robust effector functions. These primed cells persisted long term in postpartum animals, frequently maintained a programmed death 1 (PD-1) + phenotype, and failed to expand or produce cytokines robustly in response to second pregnancy or skin transplantation. However, whereas there was no impact on second pregnancy as a result of the persistence of fetal-primed memory CD8 + T cells in the mother, skin grafts bearing the same antigen were rejected more rapidly. Altogether, our data suggest that fetal antigen exposure during pregnancy induces the differentiation of long-lived maternal CD8 + T cells with context-dependent, selective effector dysfunction. This programmed effector dysfunction provides temporal and systemic restraint of maternal anti-fetal alloreactivity to promote reproductive fitness efficiently, while preserving potentially protective effector T cell responses. © Society for Leukocyte Biology.

  9. Lactobacillus rhamnosus CRL1505 nasal administration improves recovery of T-cell mediated immunity against pneumococcal infection in malnourished mice.

    Science.gov (United States)

    Barbieri, N; Herrera, M; Salva, S; Villena, J; Alvarez, S

    2017-05-30

    Immunobiotic lactic acid bacteria have become an interesting alternative for the prevention of respiratory infections. Previously, we demonstrated that the nasal administration of Lactobacillus rhamnosus CRL1505, during repletion of malnourished mice, resulted in diminished susceptibility to the challenge with the respiratory pathogen Streptococcus pneumoniae. Considering the known alterations induced by malnutrition on T lymphocytes and the importance of this cell population on the protection against respiratory pathogens, we aimed to study the effect of L. rhamnosus CRL1505 nasal administration on the recovery of T cell-mediated defences against pneumococcal infection in malnourished mice under nutritional recovery. Malnourished mice received a balanced conventional diet (BCD) for seven days or BCD for seven days with nasal L. rhamnosus CRL1505 supplementation during last two days of the treatment. After the treatments mice were infected with S. pneumoniae. Flow cytometry studies were carried out in bone marrow, thymus, spleen and lung to study T cells, and Th 1 /Th 2 cytokine profiles were determined in broncho-alveolar lavages and serum. The administration of CRL1505 strain to malnourished mice under recovery reduced quantitative and qualitative alterations of CD4 + T cells in the bone marrow, thymus, spleen and lung induced by malnutrition. In addition, CRL1505 treatment augmented Th 2 -cytokines (interleukin 10 and 4) in respiratory and systemic compartments after pneumococcal infection. These results show that modulation of CD4 + T lymphocytes induced by L. rhamnosus CRL1505 has an important role in the beneficial effect induced by this strain on the recovery of malnourished mice. These data also indicate that nasally administered L. rhamnosus CRL1505 may represent a non-invasive alternative to modulate and improve the T cell-mediated immunity against respiratory pathogens in immunocompromised malnourished hosts.

  10. Antigen-specific T cell activation independently of the MHC: chimeric antigen receptor (CAR-redirected T cells.

    Directory of Open Access Journals (Sweden)

    Hinrich eAbken

    2013-11-01

    Full Text Available Adoptive T cell therapy has recently shown powerful in initiating a lasting anti-tumor response with spectacular therapeutic success in some cases. Specific T cell therapy, however, is limited since a number of cancer cells are not recognized by T cells due to various mechanisms including the limited availability of tumor-specific T cells and deficiencies in antigen processing or major histocompatibility complex (MHC expression of cancer cells. To make adoptive cell therapy applicable for the broad variety of cancer entities, patient's T cells are engineered ex vivo with pre-defined specificity by a recombinant chimeric antigen receptor (CAR which consists in the extracellular part of an antibody-derived domain for binding with a tumor-associated antigen and in the intracellular part of a TCR-derived signaling moiety for T cell activation. The specificity of CAR mediated T cell recognition is defined by the antibody domain, is independent of MHC presentation and can be extended to any target for which an antibody is available. We discuss the advantages and limitations of MHC-independent T cell targeting by an engineered CAR and review most significant progress recently made in early stage clinical trials to treat cancer.

  11. Roquin Suppresses the PI3K-mTOR Signaling Pathway to Inhibit T Helper Cell Differentiation and Conversion of Treg to Tfr Cells.

    Science.gov (United States)

    Essig, Katharina; Hu, Desheng; Guimaraes, Joao C; Alterauge, Dominik; Edelmann, Stephanie; Raj, Timsse; Kranich, Jan; Behrens, Gesine; Heiseke, Alexander; Floess, Stefan; Klein, Juliane; Maiser, Andreas; Marschall, Susan; Hrabĕ de Angelis, Martin; Leonhardt, Heinrich; Calkhoven, Cornelis F; Noessner, Elfriede; Brocker, Thomas; Huehn, Jochen; Krug, Anne B; Zavolan, Mihaela; Baumjohann, Dirk; Heissmeyer, Vigo

    2017-12-19

    Roquin proteins preclude spontaneous T cell activation and aberrant differentiation of T follicular helper (Tfh) or T helper 17 (Th17) cells. Here we showed that deletion of Roquin-encoding alleles specifically in regulatory T (Treg) cells also caused the activation of conventional T cells. Roquin-deficient Treg cells downregulated CD25, acquired a follicular Treg (Tfr) cell phenotype, and suppressed germinal center reactions but could not protect from colitis. Roquin inhibited the PI3K-mTOR signaling pathway by upregulation of Pten through interfering with miR-17∼92 binding to an overlapping cis-element in the Pten 3' UTR, and downregulated the Foxo1-specific E3 ubiquitin ligase Itch. Loss of Roquin enhanced Akt-mTOR signaling and protein synthesis, whereas inhibition of PI3K or mTOR in Roquin-deficient T cells corrected enhanced Tfh and Th17 or reduced iTreg cell differentiation. Thereby, Roquin-mediated control of PI3K-mTOR signaling prevents autoimmunity by restraining activation and differentiation of conventional T cells and specialization of Treg cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Virus-specific HLA-restricted lysis of herpes simplex virus-infected human monocytes and macrophages mediated by cytotoxic T lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Torpey, D.J. III

    1987-01-01

    Freshly-isolated peripheral blood human monocytes and 5 day in vitro cultured macrophages were infected with herpes simplex virus type 1 (HSV-1), labeled with /sup 51/Cr, and used as target cells in a 12-14 hour cell-mediated cytotoxicity assay. Mononuclear leukocytes (MNL) from HSV-1 non-immune individuals, whether unstimulated or stimulated with HSV-1 antigen, did not mediate significant lysis of either target cell. HSV-immune MNL, both freshly-isolated and cultured for 5 days without antigen, demonstrated only low levels of natural killer (NK) cell-mediate lysis. MNL from HSV-immune individuals incubated for 5 days in vitro with HSV-1 antigen mediated significant virus-specific lysis of both target cells. Mean virus-specific lysis of autologous monocytes was 8.5(/+-/2.0)% compared to a three-fold greater virus-specific lysis of autologous macrophages. Greater than 70% of this lytic activity was mediated by Leu-11-negative, T3-positive cytotoxic T lymphocytes (CTL). Allogeneic target cells lacking a common HLA determinant were not significantly lysed while T8-positive CTL mediated infrequent lysis of target cells sharing a common HLA-A and/or HLA-B determinant. T4-positive lymphocytes were demonstrated to be the predominant cell mediating lysis of autologous target cells and allogeneic target cells sharing both HLA-A and/or HLA-B plus HLA-DR determinants with the CTL; the T4-positive cell was the sole CTL mediator of lysis of allogeneic target cells having a common HLA-DR determinant.

  13. Virus-specific HLA-restricted lysis of herpes simplex virus-infected human monocytes and macrophages mediated by cytotoxic T lymphocytes

    International Nuclear Information System (INIS)

    Torpey, D.J. III.

    1987-01-01

    Freshly-isolated peripheral blood human monocytes and 5 day in vitro cultured macrophages were infected with herpes simplex virus type 1 (HSV-1), labeled with 51 Cr, and used as target cells in a 12-14 hour cell-mediated cytotoxicity assay. Mononuclear leukocytes (MNL) from HSV-1 non-immune individuals, whether unstimulated or stimulated with HSV-1 antigen, did not mediate significant lysis of either target cell. HSV-immune MNL, both freshly-isolated and cultured for 5 days without antigen, demonstrated only low levels of natural killer (NK) cell-mediate lysis. MNL from HSV-immune individuals incubated for 5 days in vitro with HSV-1 antigen mediated significant virus-specific lysis of both target cells. Mean virus-specific lysis of autologous monocytes was 8.5(/+-/2.0)% compared to a three-fold greater virus-specific lysis of autologous macrophages. Greater than 70% of this lytic activity was mediated by Leu-11-negative, T3-positive cytotoxic T lymphocytes (CTL). Allogeneic target cells lacking a common HLA determinant were not significantly lysed while T8-positive CTL mediated infrequent lysis of target cells sharing a common HLA-A and/or HLA-B determinant. T4-positive lymphocytes were demonstrated to be the predominant cell mediating lysis of autologous target cells and allogeneic target cells sharing both HLA-A and/or HLA-B plus HLA-DR determinants with the CTL; the T4-positive cell was the sole CTL mediator of lysis of allogeneic target cells having a common HLA-DR determinant

  14. Tumor-specific CD4+ T cells develop cytotoxic activity and eliminate virus-induced tumor cells in the absence of regulatory T cells.

    Science.gov (United States)

    Akhmetzyanova, Ilseyar; Zelinskyy, Gennadiy; Schimmer, Simone; Brandau, Sven; Altenhoff, Petra; Sparwasser, Tim; Dittmer, Ulf

    2013-02-01

    The important role of tumor-specific cytotoxic CD8(+) T cells is well defined in the immune control of the tumors, but the role of effector CD4(+) T cells is poorly understood. In the current research, we have used a murine retrovirus-induced tumor cell line of C57BL/6 mouse origin, namely FBL-3 cells, as a model to study basic mechanisms of immunological control and escape during tumor formation. This study shows that tumor-specific CD4(+) T cells are able to protect against virus-induced tumor cells. We show here that there is an expansion of tumor-specific CD4(+) T cells producing cytokines and cytotoxic molecule granzyme B (GzmB) in the early phase of tumor growth. Importantly, we demonstrate that in vivo depletion of regulatory T cells (Tregs) and CD8(+) T cells in FBL-3-bearing DEREG transgenic mice augments IL-2 and GzmB production by CD4(+) T cells and increases FV-specific CD4(+) T-cell effector and cytotoxic responses leading to the complete tumor regression. Therefore, the capacity to reject tumor acquired by tumor-reactive CD4(+) T cells largely depends on the direct suppressive activity of Tregs. We suggest that a cytotoxic CD4(+) T-cell immune response may be induced to enhance resistance against oncovirus-associated tumors.

  15. A novel method to generate T-cell receptor-deficient chimeric antigen receptor T cells.

    Science.gov (United States)

    Kamiya, Takahiro; Wong, Desmond; Png, Yi Tian; Campana, Dario

    2018-03-13

    Practical methods are needed to increase the applicability and efficacy of chimeric antigen receptor (CAR) T-cell therapies. Using donor-derived CAR-T cells is attractive, but expression of endogenous T-cell receptors (TCRs) carries the risk for graft-versus-host-disease (GVHD). To remove surface TCRαβ, we combined an antibody-derived single-chain variable fragment specific for CD3ε with 21 different amino acid sequences predicted to retain it intracellularly. After transduction in T cells, several of these protein expression blockers (PEBLs) colocalized intracellularly with CD3ε, blocking surface CD3 and TCRαβ expression. In 25 experiments, median TCRαβ expression in T lymphocytes was reduced from 95.7% to 25.0%; CD3/TCRαβ cell depletion yielded virtually pure TCRαβ-negative T cells. Anti-CD3ε PEBLs abrogated TCRαβ-mediated signaling, without affecting immunophenotype or proliferation. In anti-CD3ε PEBL-T cells, expression of an anti-CD19-41BB-CD3ζ CAR induced cytokine secretion, long-term proliferation, and CD19 + leukemia cell killing, at rates meeting or exceeding those of CAR-T cells with normal CD3/TCRαβ expression. In immunodeficient mice, anti-CD3ε PEBL-T cells had markedly reduced GVHD potential; when transduced with anti-CD19 CAR, these T cells killed engrafted leukemic cells. PEBL blockade of surface CD3/TCRαβ expression is an effective tool to prepare allogeneic CAR-T cells. Combined PEBL and CAR expression can be achieved in a single-step procedure, is easily adaptable to current cell manufacturing protocols, and can be used to target other T-cell molecules to further enhance CAR-T-cell therapies. © 2018 by The American Society of Hematology.

  16. Disruption of Tumor Necrosis Factor Receptor-Associated Factor 5 Exacerbates Murine Experimental Colitis via Regulating T Helper Cell-Mediated Inflammation

    Directory of Open Access Journals (Sweden)

    Jian Shang

    2016-01-01

    Full Text Available Tumor necrosis factor (TNF receptor-associated factor 5 (TRAF5 is a key mediator of TNF receptor superfamily members and is important in both T helper (Th cell immunity and the regulation of multiple signaling pathways. To clarify TRAF5’s influence on inflammatory bowel diseases (IBDs, we investigated TRAF5 deficiency’s effect on dextran sulfate sodium- (DSS- induced colitis. Colitis was induced in TRAF5 knockout (KO mice and their wild-type (WT littermates by administering 3% DSS orally for 7 days. The mice were then sacrificed, and their colons were removed. Our data suggested that KO mice were more susceptible to DSS-induced colitis. TRAF5 deficiency significantly enhanced IFN-γ, IL-4, and IL-17a mRNA and protein levels in the colons of DSS-fed mice, and the mRNA expression of T-bet and GATA-3 was also markedly elevated. However, ROR-α and ROR-γt mRNA levels did not differ between DSS-induced KO and WT mice. Flow cytometry showed increased frequencies of Th2 and IFN-γ/IL-17a-coproducing CD4+ T cells in the colons of DSS-induced KO mice. Additionally, TRAF5 deficiency significantly enhanced the activation of NF-κB in CD4+ T cells after DSS administration. These results indicated that TRAF5 deficiency significantly aggravated DSS-induced colitis, most likely by regulating Th cell-mediated inflammation.

  17. Role of receptor-mediated endocytosis in the antiangiogenic effects of human T lymphoblastic cell-derived microparticles.

    Science.gov (United States)

    Yang, Chun; Xiong, Wei; Qiu, Qian; Shao, Zhuo; Shao, Zuo; Hamel, David; Tahiri, Houda; Leclair, Grégoire; Lachapelle, Pierre; Chemtob, Sylvain; Hardy, Pierre

    2012-04-15

    Microparticles possess therapeutic potential regarding angiogenesis. We have demonstrated the contribution of apoptotic human CEM T lymphocyte-derived microparticles (LMPs) as inhibitors of angiogenic responses in animal models of inflammation and tumor growth. In the present study, we characterized the antivascular endothelial growth factor (VEGF) effects of LMPs on pathological angiogenesis in an animal model of oxygen-induced retinopathy and explored the role of receptor-mediated endocytosis in the effects of LMPs on human retinal endothelial cells (HRECs). LMPs dramatically inhibited cell growth of HRECs, suppressed VEGF-induced cell migration in vitro experiments, and attenuated VEGF-induced retinal vascular leakage in vivo. Intravitreal injections of fluorescently labeled LMPs revealed accumulation of LMPs in retinal tissue, with more than 60% reductions of the vascular density in retinas of rats with oxygen-induced neovascularization. LMP uptake experiments demonstrated that the interaction between LMPs and HRECs is dependent on temperature. In addition, endocytosis is partially dependent on extracellular calcium. RNAi-mediated knockdown of low-density lipoprotein receptor (LDLR) reduced the uptake of LMPs and attenuated the inhibitory effects of LMPs on VEGF-A protein expression and HRECs cell growth. Intravitreal injection of lentivirus-mediated RNA interference reduced LDLR protein expression in retina by 53% and significantly blocked the antiangiogenic effects of LMPs on pathological vascularization. In summary, the potent antiangiogenic LMPs lead to a significant reduction of pathological retinal angiogenesis through modulation of VEGF signaling, whereas LDLR-mediated endocytosis plays a partial, but pivotal, role in the uptake of LMPs in HRECs.

  18. 14-Deoxy-11,12-didehydroandrographolide induces DDIT3-dependent endoplasmic reticulum stress-mediated autophagy in T-47D breast carcinoma cells

    International Nuclear Information System (INIS)

    Tan, Heng Kean; Muhammad, Tengku Sifzizul Tengku; Tan, Mei Lan

    2016-01-01

    14-Deoxy-11,12-didehydroandrographolide (14-DDA), a major diterpenoid isolated from Andrographis paniculata (Burm.f.) Nees, is known to be cytotoxic and elicits a non-apoptotic cell death in T-47D breast carcinoma cells. In this study, the mechanistic toxicology properties of 14-DDA in T-47D cells were further investigated. 14-DDA is found to induce the formation of endoplasmic reticulum (ER) vacuoles and autophagosomes, with concurrent upregulation of LC3-II in the breast carcinoma cells. It stimulated an increase in cytosolic calcium concentration and caused a collapse in mitochondrial membrane potential in these cells. In addition, both DDIT3 and GADD45A, molecules implicated in ER stress pathway, were significantly upregulated. DDIT3 knockdown suppressed the formation of both ER vacuoles and autophagosomes, indicating that 14-DDA-induced ER stress and autophagy is dependent on this transcription factor. Collectively, it is possible that GADD45A/p38 MAPK/DDIT3 pathway is involved in the 14-DDA-induced ER-stress-mediated autophagy in T-47D cells. - Highlights: • The mechanistic toxicology properties of 14-DDA in T-47D breast carcinoma cells were investigated. • 14-DDA induces the formation of ER vacuoles and autophagosomes, with concurrent upregulation of LC3-II. • It stimulates an increase in cytosolic calcium concentration and causing collapse in the mitochondrial membrane potential. • Both DDIT3 and GADD45A, molecules implicated in ER stress pathway, were significantly upregulated. • 4-DDA induces ER stress-mediated autophagy in T-47D cells possibly via GADD45A/p38 MAPK/DDIT3 pathway.

  19. Autoreactive effector/memory CD4+ and CD8+ T cells infiltrating grafted and endogenous islets in diabetic NOD mice exhibit similar T cell receptor usage.

    Directory of Open Access Journals (Sweden)

    Ramiro Diz

    Full Text Available Islet transplantation provides a "cure" for type 1 diabetes but is limited in part by recurrent autoimmunity mediated by β cell-specific CD4(+ and CD8(+ T cells. Insight into the T cell receptor (TCR repertoire of effector T cells driving recurrent autoimmunity would aid the development of immunotherapies to prevent islet graft rejection. Accordingly, we used a multi-parameter flow cytometry strategy to assess the TCR variable β (Vβ chain repertoires of T cell subsets involved in autoimmune-mediated rejection of islet grafts in diabetic NOD mouse recipients. Naïve CD4(+ and CD8(+ T cells exhibited a diverse TCR repertoire, which was similar in all tissues examined in NOD recipients including the pancreas and islet grafts. On the other hand, the effector/memory CD8(+ T cell repertoire in the islet graft was dominated by one to four TCR Vβ chains, and specific TCR Vβ chain usage varied from recipient to recipient. Similarly, islet graft- infiltrating effector/memory CD4(+ T cells expressed a limited number of prevalent TCR Vβ chains, although generally TCR repertoire diversity was increased compared to effector/memory CD8(+ T cells. Strikingly, the majority of NOD recipients showed an increase in TCR Vβ12-bearing effector/memory CD4(+ T cells in the islet graft, most of which were proliferating, indicating clonal expansion. Importantly, TCR Vβ usage by effector/memory CD4(+ and CD8(+ T cells infiltrating the islet graft exhibited greater similarity to the repertoire found in the pancreas as opposed to the draining renal lymph node, pancreatic lymph node, or spleen. Together these results demonstrate that effector/memory CD4(+ and CD8(+ T cells mediating autoimmune rejection of islet grafts are characterized by restricted TCR Vβ chain usage, and are similar to T cells that drive destruction of the endogenous islets.

  20. Radiation Therapy Induces Macrophages to Suppress T-Cell Responses Against Pancreatic Tumors in Mice.

    Science.gov (United States)

    Seifert, Lena; Werba, Gregor; Tiwari, Shaun; Giao Ly, Nancy Ngoc; Nguy, Susanna; Alothman, Sara; Alqunaibit, Dalia; Avanzi, Antonina; Daley, Donnele; Barilla, Rocky; Tippens, Daniel; Torres-Hernandez, Alejandro; Hundeyin, Mautin; Mani, Vishnu R; Hajdu, Cristina; Pellicciotta, Ilenia; Oh, Philmo; Du, Kevin; Miller, George

    2016-06-01

    murine PDA to acquire an immune-suppressive phenotype and disabled T-cell-mediated anti-tumor responses. MCSF blockade negates this effect, allowing radiation to have increased efficacy in slowing tumor growth. Copyright © 2016 AGA Institute. Published by Elsevier Inc. All rights reserved.

  1. Adoptive immunotherapy mediated by ex vivo expanded natural killer T cells against CD1d-expressing lymphoid neoplasms.

    Science.gov (United States)

    Bagnara, Davide; Ibatici, Adalberto; Corselli, Mirko; Sessarego, Nadia; Tenca, Claudya; De Santanna, Amleto; Mazzarello, Andrea; Daga, Antonio; Corvò, Renzo; De Rossi, Giulio; Frassoni, Francesco; Ciccone, Ermanno; Fais, Franco

    2009-07-01

    CD1d is a monomorphic antigen presentation molecule expressed in several hematologic malignancies. Alpha-galactosylceramide (alpha-GalCer) is a glycolipid that can be presented to cytotoxic CD1d-restricted T cells. These reagents represent a potentially powerful tool for cell mediated immunotherapy. We set up an experimental model to evaluate the use of adoptively transferred cytotoxic CD1d-restricted T cells and alpha-GalCer in the treatment of mice engrafted with CD1d(+) lymphoid neoplastic cells. To this end the C1R cell line was transfected with CD1c or CD1d molecules. In addition, upon retroviral infection firefly luciferase was expressed on C1R transfected cell lines allowing the evaluation of tumor growth in xenografted immunodeficient NOD/SCID mice. The C1R-CD1d cell line was highly susceptible to specific CD1d-restricted T cell cytotoxicity in the presence alpha-GalCer in vitro. After adoptive transfer of CD1d-restricted T cells and alpha-GalCer to mice engrafted with both C1R-CD1c and C1R-CD1d, a reduction in tumor growth was observed only in CD1d(+) masses. In addition, CD1d-restricted T-cell treatment plus alpha-GalCer eradicated small C1R-CD1d(+) nodules. Immunohistochemical analysis revealed that infiltrating NKT cells were mainly observed in CD1d nodules. Our results indicate that ex vivo expanded cytotoxic CD1d-restricted T cells and alpha-GalCer may represent a new immunotherapeutic tool for treatment of CD1d(+) hematologic malignancies.

  2. [gammadelta T cells stimulated by zoledronate kill osteosarcoma cells].

    Science.gov (United States)

    Jiang, Hui; Xu, Qiang; Yang, Chao; Cao, Zhen-Guo; Li, Zhao-Xu; Ye, Zhao-Ming

    2010-12-01

    To investigate the cytotoxicity of human γδT cells from PBMCs stimulated by zoledronate against osteosarcoma cell line HOS in vitro and in vivo and evaluate the relavent pathways. The peripheral blood mononuclear cells (PBMCs)of healthy donors were stimulated by single dose zoledronate and cultured in the present of IL-2 for two weeks, analysising the percentage of γδT cells on a FACSCalibur cytometer.Study the cytotoxicity of γδT cells against the osteosarcoma line HOS using LDH release assay kit. Pre-treatment of γδT cells with anti-human γδTCR antibody, anti-human NKG2D antibody and concanamycin A to bolck the relavent pathways for evaluating the mechenisms of its cytotoxicity. In vivo, BALB/c mice were inoculated subcutaneously osteosarcoma cell HOS for developing hypodermal tumors. And they were randomized into two groups: unteated group, γδT cell therapy group. Tumor volume and weight of the two groups were compared. After two weeks of culture, γδT cells from zoledronate-stimulated PBMCs could reach (95±3)%. When the E:T as 6:1, 12:1, 25:1, 50:1, the percentage of osteosarcoma cell HOS killed by γδT cells was 26.8%, 31.5%, 37.8%, 40.9%, respectively.When anti-huma γδTCR antibody, anti-human NKG2D antibody and concanamycin A blocked the relavent pathways, the percentage was 32.3%, 4.7%, 16.7% ( E:T as 25:1), respectively. In vivo, the tumor inhibition rate of the group of γδT cell therapy was 42.78%. γδT cells derived from PBMCs stimulated by zoledronate can acquired pure γδT cells. And they show strong cytoxicity against osteosarcoma cell line HOS in vitro and in vivo.

  3. T cell resistance to activation by dendritic cells requires long-term culture in simulated microgravity

    Science.gov (United States)

    Bradley, Jillian H.; Stein, Rachel; Randolph, Brad; Molina, Emily; Arnold, Jennifer P.; Gregg, Randal K.

    2017-11-01

    Immune impairment mediated by microgravity threatens the success of space exploration requiring long-duration spaceflight. The cells of most concern, T lymphocytes, coordinate the host response against microbial and cancerous challenges leading to elimination and long-term protection. T cells are activated upon recognition of specific microbial peptides bound on the surface of antigen presenting cells, such as dendritic cells (DC). Subsequently, this engagement results in T cell proliferation and differentiation into effector T cells driven by autocrine interleukin-2 (IL-2) and other cytokines. Finally, the effector T cells acquire the weaponry needed to destroy microbial invaders and tumors. Studies conducted on T cells during spaceflight, or using Earth-based culture systems, have shown reduced production of cytokines, proliferation and effector functions as compared to controls. This may account for the cases of viral reactivation events and opportunistic infections associated with astronauts of numerous missions. This work has largely been based upon the outcome of T cell activation by stimulatory factors that target select T cell signaling pathways rather than the complex, signaling events related to the natural process of antigen presentation by DC. This study tested the response of an ovalbumin peptide-specific T cell line, OT-II TCH, to activation by DC when the T cells were cultured 24-120 h in a simulated microgravity (SMG) environment generated by a rotary cell culture system. Following 72 h culture of T cells in SMG (SMG-T) or control static (Static-T) conditions, IL-2 production by the T cells was reduced in SMG-T cells compared to Static-T cells upon stimulation by phorbol 12-myristate 13-acetate (PMA) and ionomycin. However, when the SMG-T cells were stimulated with DC and peptide, IL-2 was significantly increased compared to Static-T cells. Such enhanced IL-2 production by SMG-T cells peaked at 72 h SMG culture time and decreased thereafter. When

  4. T cell-B cell interactions in primary immunodeficiencies.

    Science.gov (United States)

    Tangye, Stuart G; Deenick, Elissa K; Palendira, Umaimainthan; Ma, Cindy S

    2012-02-01

    Regulated interactions between cells of the immune system facilitate the generation of successful immune responses, thereby enabling efficient neutralization and clearance of pathogens and the establishment of both cell- and humoral-mediated immunological memory. The corollary of this is that impediments to efficient cell-cell interactions, normally necessary for differentiation and effector functions of immune cells, underly the clinical features and disease pathogenesis of primary immunodeficiencies. In affected individuals, these defects manifest as impaired long-term humoral immunity and susceptibility to infection by specific pathogens. In this review, we discuss the importance of, and requirements for, effective interactions between B cells and T cells during the formation of CD4(+) T follicular helper cells and the elicitation of cytotoxic function of virus-specific CD8(+) T cells, as well as how these processes are abrogated in primary immunodeficiencies due to loss-of-function mutations in defined genes. © 2012 New York Academy of Sciences.

  5. Neurofibromin 1 Impairs Natural Killer T-Cell-Dependent Antitumor Immunity against a T-Cell Lymphoma

    Directory of Open Access Journals (Sweden)

    Jianyun Liu

    2018-01-01

    Full Text Available Neurofibromin 1 (NF1 is a tumor suppressor gene encoding a Ras GTPase that negatively regulates Ras signaling pathways. Mutations in NF1 are linked to neurofibromatosis type 1, juvenile myelomonocytic leukemia and Watson syndrome. In terms of antitumor immunity, CD1d-dependent natural killer T (NKT cells play an important role in the innate antitumor immune response. Generally, Type-I NKT cells protect (and Type-II NKT cells impair host antitumor immunity. We have previously shown that CD1d-mediated antigen presentation to NKT cells is regulated by cell signaling pathways. To study whether a haploinsufficiency in NF1 would affect CD1d-dependent activation of NKT cells, we analyzed the NKT-cell population as well as the functional expression of CD1d in Nf1+/− mice. Nf1+/− mice were found to have similar levels of NKT cells as wildtype (WT littermates. Interestingly, however, reduced CD1d expression was observed in Nf1+/− mice compared with their WT littermates. When inoculated with a T-cell lymphoma in vivo, Nf1+/− mice survived longer than their WT littermates. Furthermore, blocking CD1d in vivo significantly enhanced antitumor activity in WT, but not in Nf1+/− mice. In contrast, a deficiency in Type-I NKT cells increased antitumor activity in Nf1+/− mice, but not in WT littermates. Therefore, these data suggest that normal NF1 expression impairs CD1d-mediated NKT-cell activation and antitumor activity against a T-cell lymphoma.

  6. Immunosuppression after Sepsis: Systemic Inflammation and Sepsis Induce a Loss of Naïve T-Cells but No Enduring Cell-Autonomous Defects in T-Cell Function

    Science.gov (United States)

    Markwart, Robby; Condotta, Stephanie A.; Requardt, Robert P.; Borken, Farina; Schubert, Katja; Weigel, Cynthia; Bauer, Michael; Griffith, Thomas S.; Förster, Martin; Brunkhorst, Frank M.; Badovinac, Vladimir P.; Rubio, Ignacio

    2014-01-01

    Sepsis describes the life-threatening systemic inflammatory response (SIRS) of an organism to an infection and is the leading cause of mortality on intensive care units (ICU) worldwide. An acute episode of sepsis is characterized by the extensive release of cytokines and other mediators resulting in a dysregulated immune response leading to organ damage and/or death. This initial pro-inflammatory burst often transits into a state of immune suppression characterised by loss of immune cells and T-cell dysfunction at later disease stages in sepsis survivors. However, despite these appreciations, the precise nature of the evoked defect in T-cell immunity in post-acute phases of SIRS remains unknown. Here we present an in-depth functional analysis of T-cell function in post-acute SIRS/sepsis. We document that T-cell function is not compromised on a per cell basis in experimental rodent models of infection-free SIRS (LPS or CpG) or septic peritonitis. Transgenic antigen-specific T-cells feature an unaltered cytokine response if challenged in vivo and ex vivo with cognate antigens. Isolated CD4+/CD8+ T-cells from post-acute septic animals do not exhibit defects in T-cell receptor-mediated activation at the the level of receptor-proximal signalling, activation marker upregulation or expansion. However, SIRS/sepsis induced transient lymphopenia and gave rise to an environment of immune attenuation at post acute disease stages. Thus, systemic inflammation has an acute impact on T-cell numbers and adaptive immunity, but does not cause major cell-autonomous enduring functional defects in T-cells. PMID:25541945

  7. T cell telomere length in HIV-1 infection: no evidence for increased CD4+ T cell turnover

    NARCIS (Netherlands)

    Wolthers, K. C.; Bea, G.; Wisman, A.; Otto, S. A.; de Roda Husman, A. M.; Schaft, N.; de Wolf, F.; Goudsmit, J.; Coutinho, R. A.; van der Zee, A. G.; Meyaard, L.; Miedema, F.

    1996-01-01

    Progression to acquired immunodeficiency syndrome (AIDS) has been related to exhaustion of the regenerative capacity of the immune system resulting from high T cell turnover. Analysis of telomeric terminal restriction fragment (TRF) length, a marker for cellular replicative history, showed that

  8. Targetless T cells in cancer immunotherapy

    DEFF Research Database (Denmark)

    thor Straten, Eivind Per; Garrido, Federico

    2016-01-01

    Attention has recently focused on new cancer immunotherapy protocols aiming to activate T cell mediated anti-tumor responses. To this end, administration of antibodies that target inhibitory molecules regulating T-cell cytotoxicity has achieved impressive clinical responses, as has adoptive cell...... infiltrate tumor tissues and destroy HLA class I positive tumor cells expressing the specific antigen. In fact, current progress in the field of cancer immune therapy is based on the capacity of T cells to kill cancer cells that present tumor antigen in the context on an HLA class I molecule. However......, it is also well established that cancer cells are often characterized by loss or down regulation of HLA class I molecules, documented in a variety of human tumors. Consequently, immune therapy building on CD8 T cells will be futile in patients harboring HLA class-I negative or deficient cancer cells...

  9. T cell ignorance is bliss: T cells are not tolerized by Langerhans cells presenting human papillomavirus antigens in the absence of costimulation

    Directory of Open Access Journals (Sweden)

    Andrew W. Woodham

    2016-12-01

    Full Text Available Human papillomavirus type 16 (HPV16 infections are intra-epithelial, and thus, HPV16 is known to interact with Langerhans cells (LCs, the resident epithelial antigen-presenting cells (APCs. The current paradigm for APC-mediated induction of T cell anergy is through delivery of T cell receptor signals via peptides on MHC molecules (signal 1, but without costimulation (signal 2. We previously demonstrated that LCs exposed to HPV16 in vitro present HPV antigens to T cells without costimulation, but it remained uncertain if such T cells would remain ignorant, become anergic, or in the case of CD4+ T cells, differentiate into Tregs. Here we demonstrate that Tregs were not induced by LCs presenting only signal 1, and through a series of in vitro immunizations show that CD8+ T cells receiving signal 1+2 from LCs weeks after consistently receiving signal 1 are capable of robust effector functions. Importantly, this indicates that T cells are not tolerized but instead remain ignorant to HPV, and are activated given the proper signals. Keywords: T cell anergy, T cell ignorance, Immune tolerance, Human papillomavirus, HPV16, Langerhans cells

  10. CD147-mediated chemotaxis of CD4+CD161+ T cells may contribute to local inflammation in rheumatoid arthritis.

    Science.gov (United States)

    Lv, Minghua; Miao, Jinlin; Zhao, Peng; Luo, Xing; Han, Qing; Wu, Zhenbiao; Zhang, Kui; Zhu, Ping

    2018-01-01

    CD161 is used as a surrogate marker for Th17 cells, which are implicated in the pathogenesis of rheumatoid arthritis (RA). In this study, we evaluated the percentage, clinical significance, and CD98 and CD147 expression of CD4 + CD161 + T cells. The potential role of CD147 and CD98 in cyclophilin A-induced chemotaxis of CD4 + CD161 + T cells was analyzed. Thirty-seven RA patients, 15 paired synovial fluid (SF) of RA, and 22 healthy controls were recruited. The cell populations and surface expression of CD98 and CD147 were analyzed by flow cytometry. Spearman's rank correlation coefficient and multiple linear regression were applied to calculate the correlations. Chemotaxis assay was used to investigate CD4 + CD161 + T cell migration. We found that the percentage of CD4 + CD161 + T cells and their expression of CD147 and CD98 in SF were higher than in the peripheral blood of RA patients. Percentage of SF CD4 + CD161 + T cells was positively correlated with 28-Joint Disease Activity Score (DAS28). CD147 monoclonal antibody (HAb18) attenuated the chemotactic ability of CD4 + CD161 + T cells. An increased CD4 + CD161 + T cell percentage and expression of CD147 and CD98 were shown in RA SF. Percentage of SF CD4 + CD161 + T cells can be used as a predictive marker of disease activity in RA. CD147 block significantly decreased the chemotactic index of CD4 + CD161 + cells induced by cyclophilin A (CypA). These results imply that the accumulation of CD4 + CD161 + T cells in SF and their high expression of CD147 may be associated with CypA-mediated chemotaxis and contribute to local inflammation in RA.

  11. Recognition of microbial glycolipids by Natural Killer T cells

    Directory of Open Access Journals (Sweden)

    Dirk Michael Zajonc

    2015-08-01

    Full Text Available T cells can recognize microbial antigens when presented by dedicated antigen-presenting molecules. While peptides are presented by classical members of the Major Histocompatibility (MHC family (MHC I and II, lipids, glycolipids and lipopeptides can be presented by the non-classical MHC member CD1. The best studied subset of lipid-reactive T cells are Type I Natural killer T (iNKT cells that recognize a variety of different antigens when presented by the non-classical MHCI homolog CD1d. iNKT cells have been shown to be important for the protection against various microbial pathogens, including B. burgdorferi the causative agents of Lyme disease and S. pneumoniae, which causes pneumococcal meningitis and community-acquired pneumonia. Both pathogens carry microbial glycolipids that can trigger the T cell antigen receptor (TCR, leading to iNKT cell activation. iNKT cells have an evolutionary conserved TCR alpha chain, yet retain the ability to recognize structurally diverse glycolipids. They do so using a conserved recognition mode, in which the TCR enforces a conserved binding orientation on CD1d. TCR binding is accompanied by structural changes within the TCR binding site of CD1d, as well as the glycolipid antigen itself. In addition to direct recognition of microbial antigens, iNKT cells can also be activated by a combination of cytokines (IL-12/IL-18 and TCR stimulation. Many microbes carry TLR antigens and microbial infections can lead to TLR activation. The subsequent cytokine response in turn lower the threshold of TCR mediated iNKT cell activation, especially when weak microbial or even self-antigens are presented during the cause of the infection. In summary, iNKT cells can be directly activated through TCR triggering of strong antigens, while cytokines produced by the innate immune response may be necessary for TCR triggering and iNKT cell activation in the presence of weak antigens. Here we will review the molecular basis of iNKT cell

  12. Eosinophilia of dystrophin-deficient muscle is promoted by perforin-mediated cytotoxicity by T cell effectors

    Science.gov (United States)

    Cai, B.; Spencer, M. J.; Nakamura, G.; Tseng-Ong, L.; Tidball, J. G.

    2000-01-01

    Previous investigations have shown that cytotoxic T lymphocytes (CTLs) contribute to muscle pathology in the dystrophin-null mutant mouse (mdx) model of Duchenne muscular dystrophy through perforin-dependent and perforin-independent mechanisms. We have assessed whether the CTL-mediated pathology includes the promotion of eosinophilia in dystrophic muscle, and thereby provides a secondary mechanism through which CTLs contribute to muscular dystrophy. Quantitative immunohistochemistry confirmed that eosinophilia is a component of the mdx dystrophy. In addition, electron microscopic observations show that eosinophils traverse the basement membrane of mdx muscle fibers and display sites of close apposition of eosinophil and muscle membranes. The close membrane apposition is characterized by impingement of eosinophilic rods of major basic protein into the muscle cell membrane. Transfer of mdx splenocytes and mdx muscle extracts to irradiated C57 mice by intraperitoneal injection resulted in muscle eosinophilia in the recipient mice. Double-mutant mice lacking dystrophin and perforin showed less eosinophilia than was displayed by mdx mice that expressed perforin. Finally, administration of prednisolone, which has been shown previously to reduce the concentration of CTLs in dystrophic muscle, produced a significant reduction in eosinophilia. These findings indicate that eosinophilia is a component of the mdx pathology that is promoted by perforin-dependent cytotoxicity of effector T cells. However, some eosinophilia of mdx muscle is independent of perforin-mediated processes.

  13. The possible critical role of T-cell help in DSA-mediated graft loss.

    Science.gov (United States)

    Süsal, Caner; Slavcev, Antonij; Pham, Lien; Zeier, Martin; Morath, Christian

    2018-06-01

    In this review, we discuss a possible central role of T-cell help in severe forms of graft damage mediated by donor-specific HLA antibodies (DSA). Some kidney transplant recipients with pretransplant DSA show a high graft failure rate, whereas in other patients DSA do not harm the transplanted kidney and in most cases, disappear shortly after transplantation. Analyzing 80 desensitized highly immunized kidney transplant recipients and another multicenter cohort of 385 patients with pretransplant HLA antibodies, we reported recently that an ongoing T-cell help from an activated immune system, as measured by an increased level of soluble CD30 in serum, might be necessary for the DSA to exert a deleterious effect. Patients positive for both pretransplant DSA and sCD30 appear to require special measures, such as the elimination of DSA from the circulation, potent immunosuppression, good HLA-matching, and intense post-transplant monitoring, whereas exclusion of DSA-positive patients from transplantation in the absence of high sCD30 may not be justified in all cases, even if the pretransplant DSA are strong and complement-activating. © 2018 Steunstichting ESOT.

  14. Human influenza viruses and CD8(+) T cell responses.

    Science.gov (United States)

    Grant, Emma J; Quiñones-Parra, Sergio M; Clemens, E Bridie; Kedzierska, Katherine

    2016-02-01

    Influenza A viruses (IAVs) cause significant morbidity and mortality worldwide, despite new strain-specific vaccines being available annually. As IAV-specific CD8(+) T cells promote viral control in the absence of neutralizing antibodies, and can mediate cross-reactive immunity toward distinct IAVs to drive rapid recovery from both mild and severe influenza disease, there is great interest in developing a universal T cell vaccine. However, despite detailed studies in mouse models of influenza virus infection, there is still a paucity of data on human epitope-specific CD8(+) T cell responses to IAVs. This review focuses on our current understanding of human CD8(+) T cell immunity against distinct IAVs and discusses the possibility of achieving a CD8(+) T cell mediated-vaccine that protects against multiple, distinct IAV strains across diverse human populations. We also review the importance of CD8(+) T cell immunity in individuals highly susceptible to severe influenza infection, including those hospitalised with influenza, the elderly and Indigenous populations. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Histone methylation mediates plasticity of human FOXP3(+) regulatory T cells by modulating signature gene expressions.

    Science.gov (United States)

    He, Haiqi; Ni, Bing; Tian, Yi; Tian, Zhiqiang; Chen, Yanke; Liu, Zhengwen; Yang, Xiaomei; Lv, Yi; Zhang, Yong

    2014-03-01

    CD4(+) FOXP3(+) regulatory T (Treg) cells constitute a heterogeneous and plastic T-cell lineage that plays a pivotal role in maintaining immune homeostasis and immune tolerance. However, the fate of human Treg cells after loss of FOXP3 expression and the epigenetic mechanisms contributing to such a phenotype switch remain to be fully elucidated. In the current study, we demonstrate that human CD4(+) CD25(high) CD127(low/-) Treg cells convert to two subpopulations with distinctive FOXP3(+) and FOXP3(-) phenotypes following in vitro culture with anti-CD3/CD28 and interleukin-2. Digital gene expression analysis showed that upon in vitro expansion, human Treg cells down-regulated Treg cell signature genes, such as FOXP3, CTLA4, ICOS, IKZF2 and LRRC32, but up-regulated a set of T helper lineage-associated genes, especially T helper type 2 (Th2)-associated, such as GATA3, GFI1 and IL13. Subsequent chromatin immunoprecipitation-sequencing of these subpopulations yielded genome-wide maps of their H3K4me3 and H3K27me3 profiles. Surprisingly, reprogramming of Treg cells was associated with differential histone modifications, as evidenced by decreased abundance of permissive H3K4me3 within the down-regulated Treg cell signature genes, such as FOXP3, CTLA4 and LRRC32 loci, and increased abundance of H3K4me3 within the Th2-associated genes, such as IL4 and IL5; however, the H3K27me3 modification profile was not significantly different between the two subpopulations. In conclusion, this study revealed that loss of FOXP3 expression from human Treg cells during in vitro expansion can induce reprogramming to a T helper cell phenotype with a gene expression signature dominated by Th2 lineage-associated genes, and that this cell type conversion may be mediated by histone methylation events. © 2013 John Wiley & Sons Ltd.

  16. Histone methylation mediates plasticity of human FOXP3+ regulatory T cells by modulating signature gene expressions

    Science.gov (United States)

    He, Haiqi; Ni, Bing; Tian, Yi; Tian, Zhiqiang; Chen, Yanke; Liu, Zhengwen; Yang, Xiaomei; Lv, Yi; Zhang, Yong

    2014-01-01

    CD4+ FOXP3+ regulatory T (Treg) cells constitute a heterogeneous and plastic T-cell lineage that plays a pivotal role in maintaining immune homeostasis and immune tolerance. However, the fate of human Treg cells after loss of FOXP3 expression and the epigenetic mechanisms contributing to such a phenotype switch remain to be fully elucidated. In the current study, we demonstrate that human CD4+ CD25high CD127low/− Treg cells convert to two subpopulations with distinctive FOXP3+ and FOXP3− phenotypes following in vitro culture with anti-CD3/CD28 and interleukin-2. Digital gene expression analysis showed that upon in vitro expansion, human Treg cells down-regulated Treg cell signature genes, such as FOXP3, CTLA4, ICOS, IKZF2 and LRRC32, but up-regulated a set of T helper lineage-associated genes, especially T helper type 2 (Th2)-associated, such as GATA3, GFI1 and IL13. Subsequent chromatin immunoprecipitation-sequencing of these subpopulations yielded genome-wide maps of their H3K4me3 and H3K27me3 profiles. Surprisingly, reprogramming of Treg cells was associated with differential histone modifications, as evidenced by decreased abundance of permissive H3K4me3 within the down-regulated Treg cell signature genes, such as FOXP3, CTLA4 and LRRC32 loci, and increased abundance of H3K4me3 within the Th2-associated genes, such as IL4 and IL5; however, the H3K27me3 modification profile was not significantly different between the two subpopulations. In conclusion, this study revealed that loss of FOXP3 expression from human Treg cells during in vitro expansion can induce reprogramming to a T helper cell phenotype with a gene expression signature dominated by Th2 lineage-associated genes, and that this cell type conversion may be mediated by histone methylation events. PMID:24152290

  17. Ethanol exacerbates T cell dysfunction after thermal injury.

    Science.gov (United States)

    Choudhry, M A; Messingham, K A; Namak, S; Colantoni, A; Fontanilla, C V; Duffner, L A; Sayeed, M M; Kovacs, E J

    2000-07-01

    To understand the mechanism of suppressed immunity following alcohol consumption and thermal injury, we analyzed T cell functions in a mouse model of acute alcohol exposure and burn injury. Mice with blood alcohol levels at approximately 100 mg/dl were given a 15% scald or sham injury. Mice were sacrificed 48 h after injury. Our data demonstrated a 20-25% decrease in Con A-mediated splenic T cell proliferation (p<0.01) and 45-50% decrease in interleukin-2 (IL-2) production (p<0.01) following burn injury compared to the T cells from sham animals. A further decrease in the proliferation (25-30%) and IL-2 production (40-45%) was detected in T cells derived from burned animals receiving alcohol as compared to burn alone. No significant change in the proliferation and IL-2 production was observed in splenic T cells derived from sham-injured mice regardless of alcohol exposure. Additionally, there was no demonstrable difference in splenocyte apoptosis in any treatment group. These results suggest that alcohol consumption prior to burn injury causes a greater decrease in T cell proliferation and IL-2 production compared to either burn or alcohol injury alone that may further attenuate the cell-mediated immunity and thus enhance susceptibility to infection.

  18. NSOM/QD-Based Visualization of GM1 Serving as Platforms for TCR/CD3 Mediated T-Cell Activation

    Directory of Open Access Journals (Sweden)

    Liyun Zhong

    2013-01-01

    Full Text Available Direct molecular imaging of nanoscale relationship between T-cell receptor complexes (TCR/CD3 and gangliosidosis GM1 before and after T-cell activation has not been reported. In this study, we made use of our expertise of near-field scanning optical microscopy(NSOM/immune-labeling quantum dots- (QD-based dual-color imaging system to visualize nanoscale profiles for distribution and organization of TCR/CD3, GM1, as well as their nanospatial relationship and their correlation with PKCθ signaling cascade during T-cell activation. Interestingly, after anti-CD3/anti-CD28 Ab co-stimulation, both TCR/CD3 and GM1 were clustered to form nanodomains; moreover, all of TCR/CD3 nanodomains were colocalized with GM1 nanodomains, indicating that the formation of GM1 nanodomains was greatly correlated with TCR/CD3 mediated signaling. Specially, while T-cells were pretreated with PKCθ signaling inhibitor rottlerin to suppress IL-2 cytokine production, no visible TCR/CD3 nanodomains appeared while a lot of GM1 nanodomains were still observed. However, while T-cells are pretreated with PKCαβ signaling inhibitor GÖ6976 to suppress calcium-dependent manner, all of TCR/CD3 nanodomains were still colocalized with GM1 nanodomains. These findings possibly support the notion that the formation of GM1 nanodomains indeed serves as platforms for the recruitment of TCR/CD3 nanodomains, and TCR/CD3 nanodomains are required for PKCθ signaling cascades and T-cell activation

  19. Nitric oxide and bcl-2 mediated the apoptosis induced by nickel(II) in human T hybridoma cells

    International Nuclear Information System (INIS)

    Guan Fuqin; Zhang Dongmei; Wang Xinchang; Chen Junhui

    2007-01-01

    Although effects of nickel(II) on the immune system have long been recognized, little is known about the effects of nickel(II) on the induction of apoptosis and related signaling events in T cells. In the present study, we investigated the roles and signaling pathways of nickel(II) in the induction of apoptosis in a human T cell line jurkat. The results showed that the cytotoxic effects of Ni involved significant morphological changes and chromosomal condensation (Hoechst 33258 staining). Analyses of hypodiploid cells and FITC-Annexin V and PI double staining showed significant increase of apoptosis in jurkat cells 6, 12 and 24 h after nickel(II) treatment. Flow cytometry analysis also revealed that the loss of mitochondrial membrane potential (MMP) occurred concomitantly with the onset of NiCl 2 -induced apoptosis. Induction of apoptotic cell death by nickel was mediated by reduction of bcl-2 expression. Furthermore, nickel stimulated the generation of nitric oxide (NO). These results suggest that nickel(II) chloride induces jurkat cells apoptosis via nitric oxide generation, mitochondrial depolarization and bcl-2 suppression

  20. CCR5 and CXCR3 are dispensable for liver infiltration, but CCR5 protects against virus-induced T-cell-mediated hepatic steatosis

    DEFF Research Database (Denmark)

    Holst, P J; Orskov, C; Qvortrup, K

    2007-01-01

    CCR5 and CXCR3 are important molecules in regulating the migration of activated lymphocytes. Thus, the majority of tissue-infiltrating T cells found in the context of autoimmune conditions and viral infections express CCR5 and CXCR3, and the principal chemokine ligands are expressed within inflam...... of CCR5 is associated with the induction of CD8(+) T-cell-mediated immunopathology consisting of marked hepatic microvesicular steatosis....

  1. Critical roles for LIGHT and its receptors in generating T cell-mediated immunity during Leishmania donovani infection.

    Directory of Open Access Journals (Sweden)

    Amanda C Stanley

    2011-10-01

    Full Text Available LIGHT (TNFSF14 is a member of the TNF superfamily involved in inflammation and defence against infection. LIGHT signals via two cell-bound receptors; herpes virus entry mediator (HVEM and lymphotoxin-beta receptor (LTβR. We found that LIGHT is critical for control of hepatic parasite growth in mice with visceral leishmaniasis (VL caused by infection with the protozoan parasite Leishmania donovani. LIGHT-HVEM signalling is essential for early dendritic cell IL-12/IL-23p40 production, and the generation of IFNγ- and TNF-producing T cells that control hepatic infection. However, we also discovered that LIGHT-LTβR interactions suppress anti-parasitic immunity in the liver in the first 7 days of infection by mechanisms that restrict both CD4(+ T cell function and TNF-dependent microbicidal mechanisms. Thus, we have identified distinct roles for LIGHT in infection, and show that manipulation of interactions between LIGHT and its receptors may be used for therapeutic advantage.

  2. Mechanism of nuclear factor of activated T-cells mediated FasL expression in corticosterone -treated mouse Leydig tumor cells

    Directory of Open Access Journals (Sweden)

    Wang Qian

    2008-06-01

    Full Text Available Abstract Background Fas and FasL is important mediators of apoptosis. We have previously reported that the stress levels of corticosterone (CORT, glucocorticoid in rat increase expression of Fas/FasL and activate Fas/FasL signal pathway in rat Leydig cells, which consequently leads to apoptosis. Moreover, our another study showed that nuclear factor of activated T-cells (NFAT may play a potential role in up-regulation of FasL during CORT-treated rat Leydig cell. It is not clear yet how NFAT is involved in CORT-induced up-regulation of FasL. The aim of the present study is to investigate the molecular mechanisms of NFAT-mediated FasL expression in CORT-treated Leydig cells. Results Western blot analysis showed that NFAT2 expression is present in mouse Leydig tumor cell (mLTC-1. CORT-induced increase in FasL expression in mLTC-1 was ascertained by Western Blot analysis and CORT-induced increase in apoptotic frequency of mLTC-1 cells was detected by FACS with annexin-V labeling. Confocal imaging of NFAT2-GFP in mLTC-1 showed that high level of CORT stimulated NFAT translocation from the cytoplasm to the nucleus. RNA interference-mediated knockdown of NFAT2 significantly attenuated CORT-induced up-regulation of FasL expression in mLTC. These results corroborated our previous finding that NFAT2 is involved in CORT-induced FasL expression in rat Leydig cells and showed that mLTC-1 is a suitable model for investigating the mechanism of CORT-induced FasL expression. The analysis of reporter constructs revealed that the sequence between -201 and +71 of mouse FasL gene is essential for CORT-induced FasL expression. The mutation analysis demonstrated that CORT-induced FasL expression is mediated via an NFAT binding element located in the -201 to +71 region. Co-transfection studies with an NFAT2 expression vector and reporter construct containing -201 to +71 region of FasL gene showed that NFAT2 confer a strong inducible activity to the FasL promoter at its

  3. FoxP3+ regulatory T cells are distinct from leukemia cells in HTLV-1-associated adult T-cell leukemia.

    Science.gov (United States)

    Toulza, Frederic; Nosaka, Kisato; Takiguchi, Masafumi; Pagliuca, Tony; Mitsuya, Hiroaki; Tanaka, Yuetsu; Taylor, Graham P; Bangham, Charles R M

    2009-11-15

    Human T-lymphotropic virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia/lymphoma (ATLL). It has been postulated that ATLL cells might act as regulatory T cells (T(regs)) which, in common with ATLL cells, express both CD25 and FoxP3, and so contribute to the severe immune suppression typical of ATLL. We report here that the frequency of CD25(+) cells varied independently of the frequency of FoxP3(+) cells in both a cross-sectional study and in a longitudinal study of 2 patients with chronic ATLL. Furthermore, the capacity of ATLL cells to suppress proliferation of heterologous CD4(+)CD25(-) cells correlated with the frequency of CD4(+) FoxP3(+) cells but was independent of CD25 expression. Finally, the frequency of CD4(+)FoxP3(+) cells was inversely correlated with the lytic activity of HTLV-1-specific CTLs in patients with ATLL. We conclude that ATLL is not a tumor of FoxP3(+) regulatory T cells, and that a population of FoxP3(+) cells distinct from ATLL cells has regulatory functions and may impair the cell-mediated immune response to HTLV-1 in patients with ATLL.

  4. The Differentiation and Protective Function of Cytolytic CD4 T Cells in Influenza Infection

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    Deborah M. Brown

    2016-03-01

    Full Text Available CD4 T cells that recognize peptide antigen in the context of Class II MHC can differentiate into various subsets that are characterized by their helper functions. However, increasing evidence indicates that CD4 cells with direct cytolytic activity (CD4 CTL play a role in chronic, as well as, acute infections such as influenza A virus (IAV infection. In the last couple of decades, techniques to measure the frequency and activity of these cytolytic cells has demonstrated their abundance in infections such as HIV, mouse pox, murine gamma herpes virus, CMV, EBV and influenza among others. We now appreciate a greater role for CD4 CTL as direct effectors in viral infections and anti-tumor immunity through their ability to acquire perforin mediated cytolytic activity and contribution to lysis of virally infected targets or tumors. As early as the 1980s, CD4 T cell clones with cytolytic potential were identified after influenza virus infection, yet much of this early work was dependent on in vitro culture and little was known about the physiological relevance of CD4 CTL. Here, we discuss the direct role CD4 CTL play in protection against lethal IAV infection and the factors that drive the generation of perforin mediated lytic activity in CD4 cells in vivo during IAV infection. While focusing on CD4 CTL generated during IAV infection, we pull comparisons from the literature in other anti-viral and anti-tumor systems. Further, we highlight what is currently known about CD4 CTL secondary and memory responses, as well as vaccination strategies to induce these potent killer cells that provide an extra layer of cell mediated immune protection against heterosubtypic IAV infection.

  5. T cell motility as modulator of interactions with dendritic cells

    Directory of Open Access Journals (Sweden)

    Jens Volker Stein

    2015-11-01

    Full Text Available It is well established that the balance of costimulatory and inhibitory signals during interactions with dendritic cells (DCs determines T cell transition from a naïve to an activated or tolerant/anergic status. While many of these molecular interactions are well reproduced in reductionist in vitro assays, the highly dynamic motility of naïve T cells in lymphoid tissue acts as an additional lever to fine-tune their activation threshold. T cell detachment from DCs providing suboptimal stimulation allows them to search for DCs with higher levels of stimulatory signals, while storing a transient memory of short encounters. In turn, adhesion of weakly reactive T cells to DCs presenting pMHC with low affinity is prevented by lipid mediators. Finally, controlled recruitment of CD8+ T cells to cognate DC – CD4+ T cell clusters shapes memory T cell formation and the quality of the immune response. Dynamic physiological lymphocyte motility therefore constitutes a mechanism to mitigate low avidity T cell activation and to improve the search for optimal DCs, while contributing to peripheral tolerance induction in the absence of inflammation.

  6. Distinctive in vitro effects of T-cell growth cytokines on cytomegalovirus-stimulated T-cell responses of HIV-infected HAART recipients

    International Nuclear Information System (INIS)

    Patterson, Julie; Jesser, Renee; Weinberg, Adriana

    2008-01-01

    Functional immune reconstitution is limited after HAART, maintaining the interest in adjunctive immune-modulators. We compared in vitro the effects of the γ-chain T-cell growth cytokines IL-2, IL-4, IL-7 and IL-15 on cytomegalovirus-stimulated cell-mediated immunity. IL-2 and IL-15 increased cytomegalovirus-specific lymphocyte proliferation in HAART recipients, whereas IL-4 and IL-7 did not. The boosting effect of IL-2 and IL-15 on proliferation correlated with their ability to prevent late apoptosis. However, IL-2 increased the frequency of cells in early apoptosis, whereas IL-15 increased the frequency of fully viable cells. Both IL-2 and IL-15 increased cytomegalovirus-induced CD4 + and CD8 + T-cell proliferation and the synthesis of Th1 and pro-inflammatory cytokines and chemokines. However, only IL-2 increased the frequency of regulatory T cells and Th2 cytokine production, both of which have the potential to attenuate antiviral immune responses. Overall, compared to other γ-chain cytokines, IL-15 had the most favorable profile for boosting antiviral cell-mediated immunity

  7. Daratumumab depletes CD38sup>+> immune-regulatory cells, promotes T-cell expansion, and skews T-cell repertoire in multiple myeloma

    DEFF Research Database (Denmark)

    Krejcik, Jakub; Casneuf, Tineke; Nijhof, Inger S

    2016-01-01

    target non-plasma cells that express CD38, which prompted evaluation of daratumumab's effects on CD38-positive immune subpopulations. Peripheral blood (PB) and bone marrow (BM) from patients with relapsed/refractory myeloma from two daratumumab monotherapy studies were analyzed before and during therapy......Daratumumab targets CD38-expressing myeloma cells through a variety of immune-mediated mechanisms (complement-dependent cytotoxicity, antibody-dependent cell-mediated cytotoxicity, and antibody-dependent cellular phagocytosis) and direct apoptosis with cross-linking. These mechanisms may also...... and at relapse. Regulatory B cells (Bregs) and myeloid-derived suppressor cells (MDSCs), previously shown to express CD38, were evaluated for immunosuppressive activity and daratumumab sensitivity in the myeloma setting. A novel subpopulation of regulatory T cells (Tregs) expressing CD38 was identified...

  8. Cell death by pyroptosis drives CD4 T-cell depletion in HIV-1 infection

    Science.gov (United States)

    Doitsh, Gilad; Galloway, Nicole L. K.; Geng, Xin; Yang, Zhiyuan; Monroe, Kathryn M.; Zepeda, Orlando; Hunt, Peter W.; Hatano, Hiroyu; Sowinski, Stefanie; Muñoz-Arias, Isa; Greene, Warner C.

    2014-01-01

    The pathway causing CD4 T-cell death in HIV-infected hosts remains poorly understood although apoptosis has been proposed as a key mechanism. We now show that caspase-3-mediated apoptosis accounts for the death of only a small fraction of CD4 T cells corresponding to those that are both activated and productively infected. The remaining over 95% of quiescent lymphoid CD4 T cells die by caspase-1-mediated pyroptosis triggered by abortive viral infection. Pyroptosis corresponds to an intensely inflammatory form of programmed cell death in which cytoplasmic contents and pro-inflammatory cytokines, including IL-1β, are released. This death pathway thus links the two signature events in HIV infection--CD4 T-cell depletion and chronic inflammation--and creates a pathogenic vicious cycle in which dying CD4 T cells release inflammatory signals that attract more cells to die. This cycle can be broken by caspase 1 inhibitors shown to be safe in humans, raising the possibility of a new class of `anti-AIDS' therapeutics targeting the host rather than the virus.

  9. MAdCAM-1 is needed for diabetes development mediated by the T cell clone, BDC-2·5

    Science.gov (United States)

    Phillips, Jenny M; Haskins, Kathryn; Cooke, Anne

    2005-01-01

    The NOD-derived islet-reactive CD4+ T cell clone, BDC-2·5, is able to transfer diabetes to neonatal non-obese diabetic (NOD) mice but is unable to transfer disease to either adult NOD or NOD scid recipients. Transfer of diabetes to adult recipients by BDC-2·5 is only accomplished by cotransfer of CD8+ T cells from a diabetic donor. To understand why this CD4+ T cell clone is able to mediate diabetes in neonatal but not the adult recipients we examined the ability of the clone to traffic in the different recipients. Our studies showed that MAdCAM-1 has a very different expression pattern in the neonatal and adult pancreas. Blockade of this addressin prevents the clone from transferring diabetes to neonatal mice, suggesting that the differential pancreatic expression of MAdCAM-1 in neonatal and adult pancreas provides an explanation of the differences in diabetes development. PMID:16313366

  10. Cytotoxic T lymphocyte-mediated cytolysis: an example of programmed cell death in the immune system

    International Nuclear Information System (INIS)

    Duke, R.C.

    1985-01-01

    Target cells are programmed to die following interaction with cytotoxic T lymphocytes (CTLs). Within minutes of exposure to CTL the target cell's nuclear DNA is fragmented. Target cell lysis, as measured by 51 Cr release, occurs about 60 minutes after induction of DNA fragmentation. DNA fragmentation results from the action of an endonuclease which cleaves DNA in the linker region between nucleosomes. The origin of this nuclease, whether transferred to the target by the CTL or endogenous to the target cell, has not been resolved. DNA fragmentation occurs only when appropriately sensitized CTL are used and is not merely the result of cell death because killing of target cells by extreme deviation from homeostasis, by interruption of energy production, or by lysis with antibody and complement does not induce DNA cleavage. When Triton X-100 is added to target cells which have interacted with CTL, the DNA fragments do not remain in association with the nucleus. This observation suggests that breakdown of overall nuclear structure is induced concomitantly with DNA fragmentation. Morphologically, disruption of nuclear structure and DNA fragmentation are observed as widespread chromatin condensation (apoptosis). Apoptosis is observed in metabolically active target cells and is not a consequence of cell death. A cell whose DNA is extensively fragmented is condemmed to die. Induction of oligonucleosome-sized DNA is also an early event in glucocorticoid-induced thymocyte death and death of T cells upon removal of growth factor. Several similarities exist between these systems and CTL-mediated cytolysis suggesting a final common biochemical pathway for all three types of cell death

  11. Regulatory CD4 T cells inhibit HIV-1 expression of other CD4 T cell subsets via interactions with cell surface regulatory proteins.

    Science.gov (United States)

    Zhang, Mingce; Robinson, Tanya O; Duverger, Alexandra; Kutsch, Olaf; Heath, Sonya L; Cron, Randy Q

    2018-03-01

    During chronic HIV-1 infection, regulatory CD4 T cells (Tregs) frequently represent the largest subpopulation of CD4 T cell subsets, implying relative resistant to HIV-1. When HIV-1 infection of CD4 T cells was explored in vitro and ex vivo from patient samples, Tregs possessed lower levels of HIV-1 DNA and RNA in comparison with conventional effector and memory CD4 T cells. Moreover, Tregs suppressed HIV-1 expression in other CD4 T cells in an in vitro co-culture system. This suppression was mediated in part via multiple inhibitory surface proteins expressed on Tregs. Antibody blockade of CTLA-4, PD-1, and GARP on Tregs resulted in increased HIV-1 DNA integration and mRNA expression in neighboring CD4 T cells. Moreover, antibody blockade of Tregs inhibitory proteins resulted in increased HIV-1 LTR transcription in co-cultured CD4 T cells. Thus, Tregs inhibit HIV-1 infection of other CD4 T cell subsets via interactions with inhibitory cell surface proteins. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. T cell suppression by naturally occurring HLA-G-expressing regulatory CD4+ T cells is IL-10-dependent and reversible.

    Science.gov (United States)

    Huang, Yu-Hwa; Zozulya, Alla L; Weidenfeller, Christian; Schwab, Nicholas; Wiendl, Heinz

    2009-08-01

    CD4(+) T cells constitutively expressing the immune-tolerogenic HLA-G have been described recently as a new type of nT(reg) (HLA-G(pos) T(reg)) in humans. HLA-G(pos) T(reg) accumulate at sites of inflammation and are potent suppressors of T cell proliferation in vitro, suggesting their role in immune regulation. We here characterize the mechanism of how CD4(+) HLA-G(pos) T(reg) influence autologous HLA-G(neg) T(resp) function. Using a suppression system free of APC, we demonstrate a T-T cell interaction, resulting in suppression of HLA-G(neg) T(resp), which is facilitated by TCR engagement on HLA-G(pos) T(reg). Suppression is independent of cell-cell contact and is reversible, as the removal of HLA-G(pos) T(reg) from the established coculture restored the proliferative capability of responder cells. Further, HLA-G(pos) T(reg)-mediated suppression critically depends on the secretion of IL-10 but not TGF-beta.

  13. Bacterial CpG-DNA activates dendritic cells in vivo: T helper cell-independent cytotoxic T cell responses to soluble proteins.

    Science.gov (United States)

    Sparwasser, T; Vabulas, R M; Villmow, B; Lipford, G B; Wagner, H

    2000-12-01

    Receptors for conserved molecular patterns associated with microbial pathogens induce synthesis of co-stimulatory molecules and cytokines in immature dendritic cells (DC), as do antigen-reactive CD4 T helper cells via CD40 signaling. Once activated, antigen-presenting DC may activate CD8 T cell responses in a T helper cell-independent fashion. Using immunostimulatory CpG-oligonucleotides (ODN) mimicking bacterial CpG-DNA, we tested whether CpG-DNA bypasses the need for T helper cells in CTL responses towards proteins by directly activating antigen-presenting DC to transit into professional APC. We describe that immature DC in situ constitutively process soluble proteins and generate CD8 T cell determinants yet CD8 T cell responses remain abortive. Induction of primary antigen-specific CD8 cytotoxic T lymphocyte (CTL)-mediated responses becomes initiated in wild-type as well as T helper cell-deficient mice, provided soluble protein and CpG-ODN are draining into the same lymph node. Specifically we show that CpG-ODN trigger antigen-presenting immature DC within the draining lymph node to acutely up-regulate co-stimulatory molecules and produce IL-12. These results provide new insights for generating in vivo efficient CTL responses to soluble proteins which may influence vaccination strategies.

  14. Deficient CD4+ T cell priming and regression of CD8+ T cell functionality in virus-infected mice lacking a normal B cell compartment

    DEFF Research Database (Denmark)

    Christensen, Jan Pravsgaard; Kauffmann, Susanne Ørding; Thomsen, Allan Randrup

    2003-01-01

    of virus-specific CD4(+) T cells was markedly impaired in B(-/-) mice infected with either virus strain. Thus, our results indicate that B cells play an important role in antiviral immunity not only as Ab producers, but also in promoting an optimal and sustained T cell response. The T cell defects......In this study, we investigate the state of T cell-mediated immunity in B cell-deficient (B(-/-)) mice infected with two strains of lymphocytic choriomeningitis virus known to differ markedly in their capacity to persist. In B(-/-) C57BL mice infected with the more persisting virus, virus......-specific CD8(+) T cells are initially generated that are qualitatively similar to those in wild-type mice. However, although cell numbers are well sustained over time, the capacity to produce cytokines is rapidly impaired. In similarly infected B(-/-) BALB/c mice, virus-specific CD8(+) T cells are completely...

  15. Innovative T Cell-Targeted Therapy for Ovarian Cancer

    Science.gov (United States)

    2014-10-01

    cell effector functions: a blend of innate programming and acquired plasticity. Nat Rev Immunol 2010; 10(7): 467-78. 22. Gomes AQ, Martins DS...costimulator (ICOS) is critical for the development of human T(H)17 cells . Sci Transl Med 2010; 2(55): 55ra78. 36. Cua DJ, Tato CM. Innate IL-17...intestinal epithelial lympho- cytes (17, 18). In contrast, circulating γδ T cells can be found in the blood and lymphoid organs, and are dominated by γδ

  16. T cell resistance to activation by dendritic cells requires long-term culture in simulated microgravity.

    Science.gov (United States)

    Bradley, Jillian H; Stein, Rachel; Randolph, Brad; Molina, Emily; Arnold, Jennifer P; Gregg, Randal K

    2017-11-01

    Immune impairment mediated by microgravity threatens the success of space exploration requiring long-duration spaceflight. The cells of most concern, T lymphocytes, coordinate the host response against microbial and cancerous challenges leading to elimination and long-term protection. T cells are activated upon recognition of specific microbial peptides bound on the surface of antigen presenting cells, such as dendritic cells (DC). Subsequently, this engagement results in T cell proliferation and differentiation into effector T cells driven by autocrine interleukin-2 (IL-2) and other cytokines. Finally, the effector T cells acquire the weaponry needed to destroy microbial invaders and tumors. Studies conducted on T cells during spaceflight, or using Earth-based culture systems, have shown reduced production of cytokines, proliferation and effector functions as compared to controls. This may account for the cases of viral reactivation events and opportunistic infections associated with astronauts of numerous missions. This work has largely been based upon the outcome of T cell activation by stimulatory factors that target select T cell signaling pathways rather than the complex, signaling events related to the natural process of antigen presentation by DC. This study tested the response of an ovalbumin peptide-specific T cell line, OT-II TCH, to activation by DC when the T cells were cultured 24-120 h in a simulated microgravity (SMG) environment generated by a rotary cell culture system. Following 72 h culture of T cells in SMG (SMG-T) or control static (Static-T) conditions, IL-2 production by the T cells was reduced in SMG-T cells compared to Static-T cells upon stimulation by phorbol 12-myristate 13-acetate (PMA) and ionomycin. However, when the SMG-T cells were stimulated with DC and peptide, IL-2 was significantly increased compared to Static-T cells. Such enhanced IL-2 production by SMG-T cells peaked at 72 h SMG culture time and decreased thereafter

  17. Cd1b-Mediated T Cell Recognition of a Glycolipid Antigen Generated from Mycobacterial Lipid and Host Carbohydrate during Infection

    Science.gov (United States)

    Moody, D. Branch; Guy, Mark R.; Grant, Ethan; Cheng, Tan-Yun; Brenner, Michael B.; Besra, Gurdyal S.; Porcelli, Steven A.

    2000-01-01

    T cells recognize microbial glycolipids presented by CD1 proteins, but there is no information regarding the generation of natural glycolipid antigens within infected tissues. Therefore, we determined the molecular basis of CD1b-restricted T cell recognition of mycobacterial glycosylated mycolates, including those produced during tissue infection in vivo. Transfection of the T cell receptor (TCR) α and β chains from a glucose monomycolate (GMM)-specific T cell line reconstituted GMM recognition in TCR-deficient T lymphoblastoma cells. This TCR-mediated response was highly specific for natural mycobacterial glucose-6-O-(2R, 3R) monomycolate, including the precise structure of the glucose moiety, the stereochemistry of the mycolate lipid, and the linkage between the carbohydrate and the lipid. Mycobacterial production of antigenic GMM absolutely required a nonmycobacterial source of glucose that could be supplied by adding glucose to media at concentrations found in mammalian tissues or by infecting tissue in vivo. These results indicate that mycobacteria synthesized antigenic GMM by coupling mycobacterial mycolates to host-derived glucose. Specific T cell recognition of an epitope formed by interaction of host and pathogen biosynthetic pathways provides a mechanism for immune response to those pathogenic mycobacteria that have productively infected tissues, as distinguished from ubiquitous, but innocuous, environmental mycobacteria. PMID:11015438

  18. CD40L Expression Allows CD8+ T Cells to Promote Their Own Expansion and Differentiation through Dendritic Cells

    Directory of Open Access Journals (Sweden)

    Neil Q. Tay

    2017-11-01

    Full Text Available CD8+ T cells play an important role in providing protective immunity against a wide range of pathogens, and a number of different factors control their activation. Although CD40L-mediated CD40 licensing of dendritic cells (DCs by CD4+ T cells is known to be necessary for the generation of a robust CD8+ T cell response, the contribution of CD8+ T cell-expressed CD40L on DC licensing is less clear. We have previously shown that CD8+ T cells are able to induce the production of IL-12 p70 by DCs in a CD40L-dependent manner, providing some evidence that CD8+ T cell-mediated activation of DCs is possible. To better understand the role of CD40L on CD8+ T cell responses, we generated and characterized CD40L-expressing CD8+ T cells both in vitro and in vivo. We found that CD40L was expressed on 30–50% of effector CD8+ T cells when stimulated and that this expression was transient. The expression of CD40L on CD8+ T cells promoted the proliferation and differentiation of both the CD40L-expressing CD8+ T cells and the bystander effector CD8+ T cells. This process occurred via a cell-extrinsic manner and was mediated by DCs. These data demonstrate the existence of a mechanism where CD8+ T cells and DCs cooperate to maximize CD8+ T cell responses.

  19. Follicular helper T cell in immunity and autoimmunity

    Directory of Open Access Journals (Sweden)

    D. Mesquita Jr

    2016-01-01

    Full Text Available The traditional concept that effector T helper (Th responses are mediated by Th1/Th2 cell subtypes has been broadened by the recent demonstration of two new effector T helper cells, the IL-17 producing cells (Th17 and the follicular helper T cells (Tfh. These new subsets have many features in common, such as the ability to produce IL-21 and to express the IL-23 receptor (IL23R, the inducible co-stimulatory molecule ICOS, and the transcription factor c-Maf, all of them essential for expansion and establishment of the final pool of both subsets. Tfh cells differ from Th17 by their ability to home to B cell areas in secondary lymphoid tissue through interactions mediated by the chemokine receptor CXCR5 and its ligand CXCL13. These CXCR5+ CD4+ T cells are considered an effector T cell type specialized in B cell help, with a transcriptional profile distinct from Th1 and Th2 cells. The role of Tfh cells and its primary product, IL-21, on B-cell activation and differentiation is essential for humoral immunity against infectious agents. However, when deregulated, Tfh cells could represent an important mechanism contributing to exacerbated humoral response and autoantibody production in autoimmune diseases. This review highlights the importance of Tfh cells by focusing on their biology and differentiation processes in the context of normal immune response to infectious microorganisms and their role in the pathogenesis of autoimmune diseases.

  20. [Cetuximab in combination with icotinib overcomes the acquired resistance caused by EGFR T790M mutation in non-small cell lung cancer].

    Science.gov (United States)

    Wang, Meng; Zhang, Lianmin; Zhao, Xiaoliang; Liu, Jun; Chen, Yulong; Wang, Changli

    2014-09-01

    The aim of this study was to investigate the effects of combination of icotinib and cetuximab on the acquired drug resistance caused by T790M mutation of EGFR in NSCLC, and provide experimental evidence for rational treatment of NSCLC. The effects of these two agents on cell proliferation, apoptosis, and EGFR-dependent signaling were evaluated using 3-(4, 5-dimethylthiazol-2-yl)- 5-diphenyltetrazolium bromide (MTT) assay, annexin V staining, and Western blotting. The expression of molecular markers of tumor proliferation PCNA and Ki-67 protein was further examined by immunohistochemistry, and the expression of EGFR-signaling-related proteins in tissue sections taken from H1975 tumor xenografts was assessed by Western blot assay. Sensitivity to EGFR inhibitors was detected in human H1975 tumor xenograft in nude mice. The in vitro experiment showed that the proliferative ability of H1975 cells was inhibited in a dose-dependent manner, along with the increasing doses of cetuximab and icotinib, and the combination of cetuximab with icotinib resulted in a more pronounced growth inhibition of the H1975 cells. The apoptosis rate of H1975 cells after treatment with 0.5 µmol/L icotinib and 1 µg/ml cetuximab was (22.03 ± 2.41)% and that after treatment with 5 µmol/L icotinib and 10 µg/ml cetuximab was (42.75 ± 2.49)%, both were significantly higher than that after treatment with the same dose of icotinib or cetuximab alone (P icotinib treatment, but (30.8 ± 2.0) mm(3) in the cetuximab treatment group and 0 mm(3) in the cetuximab combined with icotinib group. There was a significantly decreased expression of Ki-67 and PCNA proteins and down-regulation of phosphorylation of EGFR signaling-related proteins in the cetuximab combined with icotinib group. The combination of icotinib with cetuximab can exert synergistic inhibitory effect on the acquired drug resistance caused by T790M mutation of EGFR in NSCLC H1975 cells, interrupts the EGFR-downstream signaling pathway

  1. Aryl hydrocarbon receptor (AhR-mediated perturbations in gene expression during early stages of CD4+ T-cell differentiation

    Directory of Open Access Journals (Sweden)

    Diana eRohlman

    2012-08-01

    Full Text Available Activation of the aryl hydrocarbon receptor (AhR by its prototypic ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, mediates potent suppression of T-cell dependent immune responses. The suppressive effects of TCDD occur early during CD4+ T-cell differentiation in the absence of effects on proliferation and have recently been associated with the induction of AhR-dependent regulatory T-cells (Treg. Since AhR functions as a ligand-activated transcription factor, changes in gene expression induced by TCDD during the early stages of CD4+ T-cell differentiation are likely to reflect fundamental mechanisms of AhR action. A custom panel of genes associated with T-cell differentiation was used to query changes in gene expression induced by exposure to 1 nM TCDD. CD4+ T-cells from AhR+/+ and AhR-/- mice were cultured with cytokines known to polarize the differentiation of T-cells to various effector lineages. Treatment with TCDD induced expression of Cyp1a1, Cyp1b1 and Ahrr in CD4+ T-cells from AhR+/+ mice under all culture conditions, validating the presence and activation of AhR in these cells. The highest levels of AhR activation occurred under Th17 conditions at 24 hours and Tr1 conditions at 48 hours. Unexpectedly, expression levels of most genes associated with early T-cell differentiation were unaltered by AhR activation, including lineage-specific genes that drive CD4+ T-cell polarization. The major exception was AhR-dependent up-regulation of Il22 that was seen under all culture conditions. Independent of TCDD, AhR down-regulated the expression of Il17a and Rorc based on increased expression of these genes in AhR-deficient cells across culture conditions. These findings are consistent with a role for AhR in down-regulation of inflammatory immune responses and implicate IL-22 as a potential contributor to the immunosuppressive effects of TCDD.

  2. Human T-Cell Leukemia Virus Type 1 Tax-Deregulated Autophagy Pathway and c-FLIP Expression Contribute to Resistance against Death Receptor-Mediated Apoptosis

    Science.gov (United States)

    Wang, Weimin; Zhou, Jiansuo; Shi, Juan; Zhang, Yaxi; Liu, Shilian

    2014-01-01

    ABSTRACT The human T-cell leukemia virus type 1 (HTLV-1) Tax protein is considered to play a central role in the process that leads to adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-1 Tax-expressing cells show resistance to apoptosis induced by Fas ligand (FasL) and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL). The regulation of Tax on the autophagy pathway in HeLa cells and peripheral T cells was recently reported, but the function and underlying molecular mechanism of the Tax-regulated autophagy are not yet well defined. Here, we report that HTLV-1 Tax deregulates the autophagy pathway, which plays a protective role during the death receptor (DR)-mediated apoptosis of human U251 astroglioma cells. The cellular FLICE-inhibitory protein (c-FLIP), which is upregulated by Tax, also contributes to the resistance against DR-mediated apoptosis. Both Tax-induced autophagy and Tax-induced c-FLIP expression require Tax-induced activation of IκB kinases (IKK). Furthermore, Tax-induced c-FLIP expression is regulated through the Tax-IKK-NF-κB signaling pathway, whereas Tax-triggered autophagy depends on the activation of IKK but not the activation of NF-κB. In addition, DR-mediated apoptosis is correlated with the degradation of Tax, which can be facilitated by the inhibitors of autophagy. IMPORTANCE Our study reveals that Tax-deregulated autophagy is a protective mechanism for DR-mediated apoptosis. The molecular mechanism of Tax-induced autophagy is also illuminated, which is different from Tax-increased c-FLIP. Tax can be degraded via manipulation of autophagy and TRAIL-induced apoptosis. These results outline a complex regulatory network between and among apoptosis, autophagy, and Tax and also present evidence that autophagy represents a new possible target for therapeutic intervention for the HTVL-1 related diseases. PMID:24352466

  3. Strong homeostatic TCR signals induce formation of self-tolerant virtual memory CD8 T cells.

    Science.gov (United States)

    Drobek, Ales; Moudra, Alena; Mueller, Daniel; Huranova, Martina; Horkova, Veronika; Pribikova, Michaela; Ivanek, Robert; Oberle, Susanne; Zehn, Dietmar; McCoy, Kathy D; Draber, Peter; Stepanek, Ondrej

    2018-05-11

    Virtual memory T cells are foreign antigen-inexperienced T cells that have acquired memory-like phenotype and constitute 10-20% of all peripheral CD8 + T cells in mice. Their origin, biological roles, and relationship to naïve and foreign antigen-experienced memory T cells are incompletely understood. By analyzing T-cell receptor repertoires and using retrogenic monoclonal T-cell populations, we demonstrate that the virtual memory T-cell formation is a so far unappreciated cell fate decision checkpoint. We describe two molecular mechanisms driving the formation of virtual memory T cells. First, virtual memory T cells originate exclusively from strongly self-reactive T cells. Second, the stoichiometry of the CD8 interaction with Lck regulates the size of the virtual memory T-cell compartment via modulating the self-reactivity of individual T cells. Although virtual memory T cells descend from the highly self-reactive clones and acquire a partial memory program, they are not more potent in inducing experimental autoimmune diabetes than naïve T cells. These data underline the importance of the variable level of self-reactivity in polyclonal T cells for the generation of functional T-cell diversity. © 2018 The Authors. Published under the terms of the CC BY 4.0 license.

  4. The molecular bases of δ/αβ T cell-mediated antigen recognition.

    Science.gov (United States)

    Pellicci, Daniel G; Uldrich, Adam P; Le Nours, Jérôme; Ross, Fiona; Chabrol, Eric; Eckle, Sidonia B G; de Boer, Renate; Lim, Ricky T; McPherson, Kirsty; Besra, Gurdyal; Howell, Amy R; Moretta, Lorenzo; McCluskey, James; Heemskerk, Mirjam H M; Gras, Stephanie; Rossjohn, Jamie; Godfrey, Dale I

    2014-12-15

    αβ and γδ T cells are disparate T cell lineages that can respond to distinct antigens (Ags) via the use of the αβ and γδ T cell Ag receptors (TCRs), respectively. Here we characterize a population of human T cells, which we term δ/αβ T cells, expressing TCRs comprised of a TCR-δ variable gene (Vδ1) fused to joining α and constant α domains, paired with an array of TCR-β chains. We demonstrate that these cells, which represent ∼50% of all Vδ1(+) human T cells, can recognize peptide- and lipid-based Ags presented by human leukocyte antigen (HLA) and CD1d, respectively. Similar to type I natural killer T (NKT) cells, CD1d-lipid Ag-reactive δ/αβ T cells recognized α-galactosylceramide (α-GalCer); however, their fine specificity for other lipid Ags presented by CD1d, such as α-glucosylceramide, was distinct from type I NKT cells. Thus, δ/αβTCRs contribute new patterns of Ag specificity to the human immune system. Furthermore, we provide the molecular bases of how δ/αβTCRs bind to their targets, with the Vδ1-encoded region providing a major contribution to δ/αβTCR binding. Our findings highlight how components from αβ and γδTCR gene loci can recombine to confer Ag specificity, thus expanding our understanding of T cell biology and TCR diversity. © 2014 Pellicci et al.

  5. Interleukin-7 induces HIV replication in primary naive T cells through a nuclear factor of activated T cell (NFAT)-dependent pathway

    International Nuclear Information System (INIS)

    Managlia, Elizabeth Z.; Landay, Alan; Al-Harthi, Lena

    2006-01-01

    Interleukin (IL)-7 plays several roles critical to T cell maturation, survival, and homeostasis. Because of these functions, IL-7 is under investigation as an immune-modulator for therapeutic use in lymphopenic clinical conditions, including HIV. We reported that naive T cells, typically not permissive to HIV, can be productively infected when pre-treated with IL-7. We evaluated the mechanism by which IL-7-mediates this effect. IL-7 potently up-regulated the transcriptional factor NFAT, but had no effect on NFκB. Blocking NFAT activity using a number of reagents, such as Cyclosporin A, FK-506, or the NFAT-specific inhibitor known as VIVIT peptide, all markedly reduced IL-7-mediated induction of HIV replication in naive T cells. Additional neutralization of cytokines present in IL-7-treated cultures and/or those that have NFAT-binding sequences within their promotors indicated that IL-10, IL-4, and most significantly IFNγ, all contribute to IL-7-induction of HIV productive replication in naive T cells. These data clarify the mechanism by which IL-7 can overcome the block to HIV productive infection in naive T cells, despite their quiescent cell status. These findings are relevant to the treatment of HIV disease and understanding HIV pathogenesis in the naive CD4+ T cell compartment, especially in light of the vigorous pursuit of IL-7 as an in vivo immune modulator

  6. Merkel cell polyomavirus in Merkel cell carcinogenesis: small T antigen-mediates c-Jun phosphorylation.

    Science.gov (United States)

    Wu, Julie H; Simonette, Rebecca A; Nguyen, Harrison P; Rady, Peter L; Tyring, Stephen K

    2016-06-01

    Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine skin cancer associated with the Merkel cell polyomavirus (MCPyV). The MCPyV genome, which is clonally integrated in the majority of MCCs, encodes the regulatory small T (sT) antigen. Previously, reports have established MCPyV sT antigen as a potent oncogene capable of inducing cell transformation. In the current study, we demonstrate a distinct role for c-Jun hyperactivation in MCPyV sT antigen pathogenesis. As MCPyV sT antigen's association with aggressive cancer growth has been previously established, this finding may represent a potential therapeutic target for the treatment of MCCs.

  7. Depletion of Mediator Kinase Module Subunits Represses Superenhancer-Associated Genes in Colon Cancer Cells.

    Science.gov (United States)

    Kuuluvainen, Emilia; Domènech-Moreno, Eva; Niemelä, Elina H; Mäkelä, Tomi P

    2018-06-01

    In cancer, oncogene activation is partly mediated by acquired superenhancers, which therefore represent potential targets for inhibition. Superenhancers are enriched for BRD4 and Mediator, and both BRD4 and the Mediator MED12 subunit are disproportionally required for expression of superenhancer-associated genes in stem cells. Here we show that depletion of Mediator kinase module subunit MED12 or MED13 together with MED13L can be used to reduce expression of cancer-acquired superenhancer genes, such as the MYC gene, in colon cancer cells, with a concomitant decrease in proliferation. Whereas depletion of MED12 or MED13/MED13L caused a disproportional decrease of superenhancer gene expression, this was not seen with depletion of the kinases cyclin-dependent kinase 9 (CDK8) and CDK19. MED12-MED13/MED13L-dependent superenhancer genes were coregulated by β-catenin, which has previously been shown to associate with MED12. Importantly, β-catenin depletion caused reduced binding of MED12 at the MYC superenhancer. The effect of MED12 or MED13/MED13L depletion on cancer-acquired superenhancer gene expression was more specific than and partially distinct from that of BRD4 depletion, with the most efficient inhibition seen with combined targeting. These results identify a requirement of MED12 and MED13/MED13L for expression of acquired superenhancer genes in colon cancer, implicating these Mediator subunits as potential therapeutic targets for colon cancer, alone or together with BRD4. Copyright © 2018 American Society for Microbiology.

  8. Human mesenchymal stromal cells enhance the immunomodulatory function of CD8+CD28− regulatory T cells

    Science.gov (United States)

    Liu, Qiuli; Zheng, Haiqing; Chen, Xiaoyong; Peng, Yanwen; Huang, Weijun; Li, Xiaobo; Li, Gang; Xia, Wenjie; Sun, Qiquan; Xiang, Andy Peng

    2015-01-01

    One important aspect of mesenchymal stromal cells (MSCs)-mediated immunomodulation is the recruitment and induction of regulatory T (Treg) cells. However, we do not yet know whether MSCs have similar effects on the other subsets of Treg cells. Herein, we studied the effects of MSCs on CD8+CD28− Treg cells and found that the MSCs could not only increase the proportion of CD8+CD28− T cells, but also enhance CD8+CD28−T cells' ability of hampering naive CD4+ T-cell proliferation and activation, decreasing the production of IFN-γ by activated CD4+ T cells and inducing the apoptosis of activated CD4+ T cells. Mechanistically, the MSCs affected the functions of the CD8+CD28− T cells partially through moderate upregulating the expression of IL-10 and FasL. The MSCs had no distinct effect on the shift from CD8+CD28+ T cells to CD8+CD28− T cells, but did increase the proportion of CD8+CD28− T cells by reducing their rate of apoptosis. In summary, this study shows that MSCs can enhance the regulatory function of CD8+CD28− Treg cells, shedding new light on MSCs-mediated immune regulation. PMID:25482073

  9. Cyclosporine-resistant, Rab27a-independent Mobilization of Intracellular Preformed CD40L Mediates Antigen-specific T Cell Help In Vitro

    Science.gov (United States)

    Koguchi, Yoshinobu; Gardell, Jennifer L.; Thauland, Timothy J.; Parker, David C.

    2011-01-01

    CD40L is critically important for the initiation and maintenance of adaptive immune responses. It is generally thought that CD40L expression in CD4+ T cells is regulated transcriptionally and made from new mRNA following antigen recognition. However, recent studies with two-photon microscopy revealed that the majority of cognate interactions between effector CD4+ T cells and APCs are too short for de novo synthesis of CD40L. Given that effector and memory CD4+ T cells store preformed CD40L (pCD40L) in lysosomal compartments and that pCD40L comes to the cell surface within minutes of antigenic stimulation, we and others have proposed that pCD40L might mediate T cell-dependent activation of cognate APCs during brief encounters in vivo. However, it has not been shown that this relatively small amount of pCD40L is sufficient to activate APCs, owing to the difficulty of separating the effects of pCD40L from those of de novo CD40L and other cytokines in vitro. Here we show that pCD40L surface mobilization is resistant to cyclosporine or FK506 treatment, while de novo CD40L and cytokine expression are completely inhibited. These drugs thus provide a tool to dissect the role of pCD40L in APC activation. We find that pCD40L mediates selective activation of cognate but not bystander APCs in vitro and that mobilization of pCD40L does not depend on Rab27a, which is required for mobilization of lytic granules. Therefore, effector CD4+ T cells deliver pCD40L specifically to APCs on the same time scale as the lethal hit of CTLs but with distinct molecular machinery. PMID:21677130

  10. MS4a4B, a CD20 homologue in T cells, inhibits T cell propagation by modulation of cell cycle.

    Directory of Open Access Journals (Sweden)

    Hui Xu

    2010-11-01

    Full Text Available MS4a4B, a CD20 homologue in T cells, is a novel member of the MS4A gene family in mice. The MS4A family includes CD20, FcεRIβ, HTm4 and at least 26 novel members that are characterized by their structural features: with four membrane-spanning domains, two extracellular domains and two cytoplasmic regions. CD20, FcεRIβ and HTm4 have been found to function in B cells, mast cells and hematopoietic cells respectively. However, little is known about the function of MS4a4B in T cell regulation. We demonstrate here that MS4a4B negatively regulates mouse T cell proliferation. MS4a4B is highly expressed in primary T cells, natural killer cells (NK and some T cell lines. But its expression in all malignant T cells, including thymoma and T hybridoma tested, was silenced. Interestingly, its expression was regulated during T cell activation. Viral vector-driven overexpression of MS4a4B in primary T cells and EL4 thymoma cells reduced cell proliferation. In contrast, knockdown of MS4a4B accelerated T cell proliferation. Cell cycle analysis showed that MS4a4B regulated T cell proliferation by inhibiting entry of the cells into S-G2/M phase. MS4a4B-mediated inhibition of cell cycle was correlated with upregulation of Cdk inhibitory proteins and decreased levels of Cdk2 activity, subsequently leading to inhibition of cell cycle progression. Our data indicate that MS4a4B negatively regulates T cell proliferation. MS4a4B, therefore, may serve as a modulator in the negative-feedback regulatory loop of activated T cells.

  11. MS4a4B, a CD20 homologue in T cells, inhibits T cell propagation by modulation of cell cycle.

    Science.gov (United States)

    Xu, Hui; Yan, Yaping; Williams, Mark S; Carey, Gregory B; Yang, Jingxian; Li, Hongmei; Zhang, Guang-Xian; Rostami, Abdolmohamad

    2010-11-01

    MS4a4B, a CD20 homologue in T cells, is a novel member of the MS4A gene family in mice. The MS4A family includes CD20, FcεRIβ, HTm4 and at least 26 novel members that are characterized by their structural features: with four membrane-spanning domains, two extracellular domains and two cytoplasmic regions. CD20, FcεRIβ and HTm4 have been found to function in B cells, mast cells and hematopoietic cells respectively. However, little is known about the function of MS4a4B in T cell regulation. We demonstrate here that MS4a4B negatively regulates mouse T cell proliferation. MS4a4B is highly expressed in primary T cells, natural killer cells (NK) and some T cell lines. But its expression in all malignant T cells, including thymoma and T hybridoma tested, was silenced. Interestingly, its expression was regulated during T cell activation. Viral vector-driven overexpression of MS4a4B in primary T cells and EL4 thymoma cells reduced cell proliferation. In contrast, knockdown of MS4a4B accelerated T cell proliferation. Cell cycle analysis showed that MS4a4B regulated T cell proliferation by inhibiting entry of the cells into S-G2/M phase. MS4a4B-mediated inhibition of cell cycle was correlated with upregulation of Cdk inhibitory proteins and decreased levels of Cdk2 activity, subsequently leading to inhibition of cell cycle progression. Our data indicate that MS4a4B negatively regulates T cell proliferation. MS4a4B, therefore, may serve as a modulator in the negative-feedback regulatory loop of activated T cells.

  12. Human retinal pigment epithelial cell-induced apoptosis in activated T cells

    DEFF Research Database (Denmark)

    Jørgensen, A; Wiencke, A K; la Cour, M

    1998-01-01

    PURPOSE: The immune privilege of the eye has been thought to be dependent on physical barriers and absence of lymphatic vessels. However, the immune privilege may also involve active immunologic processes, as recent studies have indicated. The purpose of the present study was to investigate whether...... human retinal pigment epithelial (RPE) cells can induce apoptosis in activated T cells. METHODS: Fas ligand (FasL) expression was detected by flow cytometry and immunohistochemistry. Cultured RPE cells were cocultured with T-cell lines and peripheral blood lymphocytes for 6 hours to 2 days. Induction...... of apoptosis was detected by 7-amino-actinomycin D and annexin V staining. RESULTS: Retinal pigment epithelial cells expressed FasL and induced apoptosis in activated Fas+ T cells. Blocking of Fas-FasL interaction with antibody strongly inhibited RPE-mediated T-cell apoptosis. Retinal pigment epithelial cells...

  13. miR-20a inhibits TCR-mediated signaling and cytokine production in human naïve CD4+ T cells.

    Directory of Open Access Journals (Sweden)

    Amarendra V Reddycherla

    Full Text Available Upon TCR stimulation by peptide-MHC complexes, CD4+ T cells undergo activation and proliferation. This process will ultimately culminate in T-cell differentiation and the acquisition of effector functions. The production of specific cytokines by differentiated CD4+ T cells is crucial for the generation of the appropriate immune response. Altered CD4+ T-cell activation and cytokine production result in chronic inflammatory conditions and autoimmune disorders. miRNAs have been shown to be important regulators of T-cell biology. In this study, we have focused our investigation on miR-20a, a member of the miR-17-92 cluster, whose expression is decreased in patients suffering from multiple sclerosis. We have found that miR-20a is rapidly induced upon TCR-triggering in primary human naïve CD4+ T cells and that its transcription is regulated in a Erk-, NF-κB-, and Ca++-dependent manner. We have further shown that overexpression of miR-20a inhibits TCR-mediated signaling but not the proliferation of primary human naïve CD4+ T cells. However, miR-20a overexpression strongly suppresses IL-10 secretion and moderately decreases IL-2, IL-6 and IL8 production, which are crucial regulators of inflammatory responses. Our study suggests that miR-20a is a new player in the regulation of TCR signaling strength and cytokine production.

  14. Downregulation of proapoptotic Bim augments IL-2-independent T-cell transformation by human T-cell leukemia virus type-1 Tax

    International Nuclear Information System (INIS)

    Higuchi, Masaya; Takahashi, Masahiko; Tanaka, Yuetsu; Fujii, Masahiro

    2014-01-01

    Human T-cell leukemia virus type 1 (HTLV-1), an etiological agent of adult T-cell leukemia, immortalizes and transforms primary human T cells in vitro in both an interleukin (IL)-2-dependent and IL-2-independent manner. Expression of the HTLV-1 oncoprotein Tax transforms the growth of the mouse T-cell line CTLL-2 from being IL-2-dependent to IL-2-independent. Withdrawal of IL-2 from normal activated T cells induces apoptosis, which is mediated through the inducible expression of several proapoptotic proteins, including Bim. In this study, we found that Tax protects IL-2-depleted T cells against Bim-induced apoptosis. Withdrawal of IL-2 from CTLL-2 cells induced a prominent increase in the level of Bim protein in CTLL-2 cells, but not in Tax-transformed CTLL-2 cells. This inhibition of Bim in Tax-transformed CTLL-2 cells was mediated by two mechanisms: downregulation of Bim mRNA and posttranscriptional reduction of Bim protein. Transient expression of Tax in CTLL-2 cells also inhibited IL-2 depletion–induced expression of Bim, however, this decrease in Bim protein expression was not due to downregulation of Bim mRNA, thus indicating that Bim mRNA downregulation in Tax-transformed CTLL-2 occurs only after long-term expression of Tax. Transient expression of Tax in CTLL-2 cells also induced Erk activation, however, this was not involved in the reduction of Bim protein. Knockdown of Bim expression in CTLL-2 cells augmented Tax-induced IL-2-independent transformation. HTLV-1 infection of human T cells also reduced their levels of Bim protein, and restoring Bim expression in HTLV-1-infected cells reduced their proliferation by inducing apoptosis. Taken together, these results indicate that Tax-induced downregulation of Bim in HTLV-1-infected T cells promotes their IL-2-independent growth, thereby supporting the persistence of HTLV-1 infection in vivo

  15. Downregulation of proapoptotic Bim augments IL-2-independent T-cell transformation by human T-cell leukemia virus type-1 Tax.

    Science.gov (United States)

    Higuchi, Masaya; Takahashi, Masahiko; Tanaka, Yuetsu; Fujii, Masahiro

    2014-12-01

    Human T-cell leukemia virus type 1 (HTLV-1), an etiological agent of adult T-cell leukemia, immortalizes and transforms primary human T cells in vitro in both an interleukin (IL)-2-dependent and IL-2-independent manner. Expression of the HTLV-1 oncoprotein Tax transforms the growth of the mouse T-cell line CTLL-2 from being IL-2-dependent to IL-2-independent. Withdrawal of IL-2 from normal activated T cells induces apoptosis, which is mediated through the inducible expression of several proapoptotic proteins, including Bim. In this study, we found that Tax protects IL-2-depleted T cells against Bim-induced apoptosis. Withdrawal of IL-2 from CTLL-2 cells induced a prominent increase in the level of Bim protein in CTLL-2 cells, but not in Tax-transformed CTLL-2 cells. This inhibition of Bim in Tax-transformed CTLL-2 cells was mediated by two mechanisms: downregulation of Bim mRNA and posttranscriptional reduction of Bim protein. Transient expression of Tax in CTLL-2 cells also inhibited IL-2 depletion-induced expression of Bim, however, this decrease in Bim protein expression was not due to downregulation of Bim mRNA, thus indicating that Bim mRNA downregulation in Tax-transformed CTLL-2 occurs only after long-term expression of Tax. Transient expression of Tax in CTLL-2 cells also induced Erk activation, however, this was not involved in the reduction of Bim protein. Knockdown of Bim expression in CTLL-2 cells augmented Tax-induced IL-2-independent transformation. HTLV-1 infection of human T cells also reduced their levels of Bim protein, and restoring Bim expression in HTLV-1-infected cells reduced their proliferation by inducing apoptosis. Taken together, these results indicate that Tax-induced downregulation of Bim in HTLV-1-infected T cells promotes their IL-2-independent growth, thereby supporting the persistence of HTLV-1 infection in vivo. © 2014 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

  16. WEHI-3 cells inhibit adipocyte differentiation in 3T3-L1 cells

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Jing [The First Affiliated Hospital, Jinan University, Guangzhou, Guangdong (China); Liu, Gexiu [Institute of Hematology, School of Medicine, Jinan University, Guangzhou, Guangdong (China); Yan, Guoyao [The First Affiliated Hospital, Jinan University, Guangzhou, Guangdong (China); He, Dongmei [Institute of Hematology, School of Medicine, Jinan University, Guangzhou, Guangdong (China); Zhou, Ying [The First Affiliated Hospital, Jinan University, Guangzhou, Guangdong (China); Chen, Shengting, E-mail: shengtingchen@sina.cn [The First Affiliated Hospital, Jinan University, Guangzhou, Guangdong (China)

    2015-06-26

    By investigating the anti-adipogenic effects of WEHI-3 cells – a murine acute myelomonocytic leukemia cell line – we sought to improve the efficiency of hematopoietic stem cell transplantation (HSCT). Analysis of Oil Red O staining and the expression of adipogenic genes, including PPARγ, C/EBPα, FAS and LPL, indicated that WEHI-3 cells significantly inhibited 3T3-L1 mouse preadipocyte cells from differentiating into adipocytes. In vivo, fat vacuoles in mice injected with WEHI-3 cells were also remarkably reduced in the murine bone marrow pimelosis model. Moreover, the key gene in the Rho signaling pathway, ROCKII, and the key gene in the Wnt signaling pathway, β-catenin, were both upregulated compared with the control group. siRNA-mediated knockdown of ROCKII and β-catenin reversed these WEHI-3-mediated anti-adipogenic effects. Taken together, these data suggest that WEHI-3 cells exert anti-adipogenic effects and that both ROCKII and β-catenin are involved in this process. - Highlights: • WEHI-3, an acute myelomonocytic leukemia cell line, inhibited 3T3-L1 preadipocyte from differentiating into adipocyte. • WEHI-3 cells can arrest 3T3-L1 cells in G0/G1 phase by secreting soluble factors and thus inhibit their proliferation. • WEHI-3 cells reduced bone marrow pimelosis in the murine model. • Both ROCKII and β-catenin were involved in the WEHI-3-mediated anti-adipogenic effects.

  17. The essential role of t cells in multiple sclerosis: A reappraisal

    Directory of Open Access Journals (Sweden)

    Cris S Constantinescu

    2014-04-01

    Full Text Available Multiple sclerosis is an inflammatory demyelinating disease of the central nervous system in which destruction of myelin and nerve axons has been shown to be mediated by immune mechanisms. Although the focus of research has been traditionally on T cells as key mediators of the immunopathology, more recent efforts at understanding this complex disorder have been directed increasingly at other cellular and humoral elements of the immune response. This review is a reappraisal of the crucial role of T cells, in particular the CD4+ helper T-cell subset, in multiple sclerosis. Recent evidence is discussed underlining the predominant contribution of T-cell-associated genes to the genome-wide association study results of multiple sclerosis susceptibility, the loss of T-cell quiescence in the conversion from clinically isolated syndrome to clinically definite multiple sclerosis, and the fact that T cells represent the main target of effective immunomodulatory and immunosuppressive treatments in multiple sclerosis.

  18. Combined local and systemic immunization is essential for durable T-cell mediated heterosubtypic immunity against influenza A virus

    DEFF Research Database (Denmark)

    Uddbäck, Ida Elin Maria; Pedersen, Line M I; Pedersen, Sara R

    2016-01-01

    nucleoprotein have previously been found to induce short-term protection in mice. In this study we confirm that systemic (subcutaneous (s.c.) immunization rapidly induced heterosubtypic protection predominantly mediated by CD8 T cells, but within three months clinical protection completely disappeared. Local......The threat from unpredictable influenza virus pandemics necessitates the development of a new type of influenza vaccine. Since the internal proteins are highly conserved, induction of T cells targeting these antigens may provide the solution. Indeed, adenoviral (Ad) vectors expressing flu...... (intranasal (i.n.)) immunization elicited delayed, but more lasting protection despite relatively inefficient immunization. However, by far, the most robust protection was induced by simultaneous, combined (i.n. + s.c.) vaccination, and, notably, in this case clinical protection lasted at least 8 months...

  19. Critical role for BIM in T cell receptor restimulation-induced death

    Directory of Open Access Journals (Sweden)

    Fleisher Thomas A

    2008-08-01

    Full Text Available Abstract Background Upon repeated or chronic antigen stimulation, activated T cells undergo a T cell receptor (TCR-triggered propriocidal cell death important for governing the intensity of immune responses. This is thought to be chiefly mediated by an extrinsic signal through the Fas-FasL pathway. However, we observed that TCR restimulation still potently induced apoptosis when this interaction was blocked, or genetically impaired in T cells derived from autoimmune lymphoproliferative syndrome (ALPS patients, prompting us to examine Fas-independent, intrinsic signals. Results Upon TCR restimulation, we specifically noted a marked increase in the expression of BIM, a pro-apoptotic Bcl-2 family protein known to mediate lymphocyte apoptosis induced by cytokine withdrawal. In fact, T cells from an ALPS type IV patient in which BIM expression is suppressed were more resistant to restimulation-induced death. Strikingly, knockdown of BIM expression rescued normal T cells from TCR-induced death to as great an extent as Fas disruption. Conclusion Our data implicates BIM as a critical mediator of apoptosis induced by restimulation as well as growth cytokine withdrawal. These findings suggest an important role for BIM in eliminating activated T cells even when IL-2 is abundant, working in conjunction with Fas to eliminate chronically stimulated T cells and maintain immune homeostasis. Reviewers This article was reviewed by Dr. Wendy Davidson (nominated by Dr. David Scott, Dr. Mark Williams (nominated by Dr. Neil Greenspan, and Dr. Laurence C. Eisenlohr.

  20. Th cells promote CTL survival and memory via acquired pMHC-I and endogenous IL-2 and CD40L signaling and by modulating apoptosis-controlling pathways.

    Directory of Open Access Journals (Sweden)

    Channakeshava Sokke Umeshappa

    Full Text Available Involvement of CD4(+ helper T (Th cells is crucial for CD8(+ cytotoxic T lymphocyte (CTL-mediated immunity. However, CD4(+ Th's signals that govern CTL survival and functional memory are still not completely understood. In this study, we assessed the role of CD4(+ Th cells with acquired antigen-presenting machineries in determining CTL fates. We utilized an adoptive co-transfer into CD4(+ T cell-sufficient or -deficient mice of OTI CTLs and OTII Th cells or Th cells with various gene deficiencies pre-stimulated in vitro by ovalbumin (OVA-pulsed dendritic cell (DCova. CTL survival was kinetically assessed in these mice using FITC-anti-CD8 and PE-H-2K(b/OVA257-264 tetramer staining by flow cytometry. We show that by acting via endogenous CD40L and IL-2, and acquired peptide-MHC-I (pMHC-I complex signaling, CD4(+ Th cells enhance survival of transferred effector CTLs and their differentiation into the functional memory CTLs capable of protecting against highly-metastasizing tumor challenge. Moreover, RT-PCR, flow cytometry and Western blot analysis demonstrate that increased survival of CD4(+ Th cell-helped CTLs is matched with enhanced Akt1/NF-κB activation, down-regulation of TRAIL, and altered expression profiles with up-regulation of prosurvival (Bcl-2 and down-regulation of proapoptotic (Bcl-10, Casp-3, Casp-4, Casp-7 molecules. Taken together, our results reveal a previously unexplored mechanistic role for CD4(+ Th cells in programming CTL survival and memory recall responses. This knowledge could also aid in the development of efficient adoptive CTL cancer therapy.

  1. Th cells promote CTL survival and memory via acquired pMHC-I and endogenous IL-2 and CD40L signaling and by modulating apoptosis-controlling pathways.

    Science.gov (United States)

    Umeshappa, Channakeshava Sokke; Xie, Yufeng; Xu, Shulin; Nanjundappa, Roopa Hebbandi; Freywald, Andrew; Deng, Yulin; Ma, Hong; Xiang, Jim

    2013-01-01

    Involvement of CD4(+) helper T (Th) cells is crucial for CD8(+) cytotoxic T lymphocyte (CTL)-mediated immunity. However, CD4(+) Th's signals that govern CTL survival and functional memory are still not completely understood. In this study, we assessed the role of CD4(+) Th cells with acquired antigen-presenting machineries in determining CTL fates. We utilized an adoptive co-transfer into CD4(+) T cell-sufficient or -deficient mice of OTI CTLs and OTII Th cells or Th cells with various gene deficiencies pre-stimulated in vitro by ovalbumin (OVA)-pulsed dendritic cell (DCova). CTL survival was kinetically assessed in these mice using FITC-anti-CD8 and PE-H-2K(b)/OVA257-264 tetramer staining by flow cytometry. We show that by acting via endogenous CD40L and IL-2, and acquired peptide-MHC-I (pMHC-I) complex signaling, CD4(+) Th cells enhance survival of transferred effector CTLs and their differentiation into the functional memory CTLs capable of protecting against highly-metastasizing tumor challenge. Moreover, RT-PCR, flow cytometry and Western blot analysis demonstrate that increased survival of CD4(+) Th cell-helped CTLs is matched with enhanced Akt1/NF-κB activation, down-regulation of TRAIL, and altered expression profiles with up-regulation of prosurvival (Bcl-2) and down-regulation of proapoptotic (Bcl-10, Casp-3, Casp-4, Casp-7) molecules. Taken together, our results reveal a previously unexplored mechanistic role for CD4(+) Th cells in programming CTL survival and memory recall responses. This knowledge could also aid in the development of efficient adoptive CTL cancer therapy.

  2. A mechanism of acquired resistance to complement-mediated lysis by Entamoeba histolytica.

    Science.gov (United States)

    Gutiérrez-Kobeh, L; Cabrera, N; Pérez-Montfort, R

    1997-04-01

    Some Entamoeba histolytica strains resist complement-mediated lysis by serum. Susceptible and resistant strains activate the complement system equivalently, but resistant amebas evade killing by membrane attack complexes. Our objective was to determine the mechanism by which trophozoites of E. histolytica resist lysis by human serum. Amebas were made resistant to lysis by incubation with increasing concentrations of normal human serum. The possibility that resistant cells ingest membrane attack complexes was explored by subcellular fractionation of susceptible and resistant trophozoites treated with sublytic concentrations of human serum containing radiolabeled C9. In both cases, most of the label was in the fractions containing plasma membrane. The susceptible strain consistently showed more label associated with these fractions than the resistant strain. Thus, the possibility that the membrane attack complexes were released to the medium was explored. Both resistant and susceptible trophozoites release to the medium similar amounts of material excluded by Sepharose CL-2B in the presence or absence of normal human serum. Labeled C9 elutes together with the main bulk of proteins from the medium: this indicates that it is not in vesicles or high molecular weight aggregates. Coincubation of susceptible amebas with lysates of resistant trophozoites confers resistance to susceptible cells within 30 min. Resistance to lysis by serum can also be acquired by susceptible amebas after coincubation with lysates from human erythrocytes or after feeding them with whole human red blood cells. Resistant but not susceptible trophozoites show intense immunofluorescent staining on their surface with anti-human erythrocytic membrane antibody. These results suggest that amebas acquire resistance to lysis by serum by incorporating into their membranes complement regulatory proteins.

  3. 4T1 Murine Mammary Carcinoma Cells Enhance Macrophage-Mediated Innate Inflammatory Responses.

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    Laurence Madera

    Full Text Available Tumor progression and the immune response are intricately linked. While it is known that cancers alter macrophage inflammatory responses to promote tumor progression, little is known regarding how cancers affect macrophage-dependent innate host defense. In this study, murine bone-marrow-derived macrophages (BMDM were exposed to murine carcinoma-conditioned media prior to assessment of the macrophage inflammatory response. BMDMs exposed to 4T1 mammary carcinoma-conditioned medium demonstrated enhanced production of pro-inflammatory cytokines tumor necrosis factor α, interleukin-6, and CCL2 in response to lipopolysaccharide (LPS while production of interleukin-10 remained unchanged. The increased LPS-induced production of pro-inflammatory cytokines was transient and correlated with enhanced cytokine production in response to other Toll-like receptor agonists, including peptidoglycan and flagellin. In addition, 4T1-conditioned BMDMs exhibited strengthened LPS-induced nitric oxide production and enhanced phagocytosis of Escherichia coli. 4T1-mediated augmentation of macrophage responses to LPS was partially dependent on the NFκB pathway, macrophage-colony stimulating factor, and actin polymerization, as well as the presence of 4T1-secreted extracellular vesicles. Furthermore, peritoneal macrophages obtained from 4T1 tumor-bearing mice displayed enhanced pro-inflammatory cytokine production in response to LPS. These results suggest that uptake of 4T1-secreted factors and actin-mediated ingestion of 4T1-secreted exosomes by macrophages cause a transient enhancement of innate inflammatory responses. Mammary carcinoma-mediated regulation of innate immunity may have significant implications for our understanding of host defense and cancer progression.

  4. Renal ischemia-reperfusion injury and adenosine 2A receptor-mediated tissue protection: the role of CD4+ T cells and IFN-gamma.

    Science.gov (United States)

    Day, Yuan-Ji; Huang, Liping; Ye, Hong; Li, Li; Linden, Joel; Okusa, Mark D

    2006-03-01

    A(2A) adenosine receptor (A(2A)R)-expressing bone marrow (BM)-derived cells contribute to the renal protective effect of A(2A) agonists in renal ischemia-reperfusion injury (IRI). We performed IRI in mice lacking T and B cells to determine whether A(2A)R expressed in CD4+ cells mediate protection from IRI. Rag-1 knockout (KO) mice were protected in comparison to wild-type (WT) mice when subjected to IRI. ATL146e, a selective A(2A) agonist, did not confer additional protection. IFN-gamma is an important early signal in IRI and is thought to contribute to reperfusion injury. Because IFN-gamma is produced by kidney cells and T cells we performed IRI in BM chimeras in which the BM of WT mice was reconstituted with BM from IFN-gamma KO mice (IFN-gamma KO-->WT chimera). We observed marked reduction in IRI in comparison to WT-->WT chimeras providing additional indirect support for the role of T cells. To confirm the role of CD4+ A(2A)R in mediating protection from IRI, Rag-1 KO mice were subjected to ischemia-reperfusion. The protection observed in Rag-1 KO mice was reversed in Rag-1 KO mice that were adoptively transferred WT CD4+ cells (WT CD4+-->Rag-1 KO) or A(2A) KO CD4+ cells (A(2A) KO CD4+-->Rag-1 KO). ATL146e reduced injury in WT CD4+-->Rag-1 KO mice but not in A(2A) KO CD4+-->Rag-1 KO mice. Rag-1 KO mice reconstituted with CD4+ cells derived from IFN-gamma KO mice (IFN-gamma CD4+-->Rag-1 KO) were protected from IRI; ATL146e conferred no additional protection. These studies demonstrate that CD4+ IFN-gamma contributes to IRI and that A(2A) agonists mediate protection from IRI through action on CD4+ cells.

  5. Murine neonatal spleen contains natural T and non-T suppressor cells capable of inhibiting adult alloreactive and newborn autoreactive T-cell proliferation.

    Science.gov (United States)

    Hooper, D C; Hoskin, D W; Gronvik, K O; Murgita, R A

    1986-05-01

    The spleen of neonatal mice is known to be a rich source of cells capable of suppressing a variety of immune functions of adult lymphocytes in vitro. From such observations has emerged the concept that the gradual development in ability to express immune functions after birth is due in part to the parallel normal physiological decay of naturally occurring regulatory suppressor cells. There is, however, some confusion in the literature as to the exact nature of the newborn of the newborn inhibitory cell type(s). In contrast to most previous reports which detect only a single type of neonatal suppressor cell, usually a T cell, we show here that newborn spleen harbors both T and non-T inhibitory cells. Both types of suppressor cells could be shown to suppress the proliferative response of adult spleen to alloantigens as well as newborn T cells reacting against self-Ia antigen in the autologous mixed lymphocyte reaction (AMLR). Newborn suppressor T cells were characterized as being non-adherent to Ig-anti-Ig affinity columns, soybean agglutinin receptor negative (SBA-), and susceptible to lysis by anti-T-cell specific antiserum plus complement. Non-T suppressor cells were identified as non-phagocytic, SBA receptor positive (SBA+), and resistant to cytotoxic treatment with anti-T-cell antibodies and complement. The apparent controversy surrounding previous reports as to the T versus non-T nature of newborn suppressor cells can be reconciled by the present observation that both types of inhibitory cells coexist in the spleen. Furthermore, the demonstration that newborn suppressor cells can effectively regulate T-cell proliferative activity mediated by other newborn cells provides more direct support for the contention that such inhibitory cells play a physiological role in controlling immune responsiveness during early ontogeny.

  6. Co-Expansion of Cytokine-Induced Killer Cells and Vγ9Vδ2 T Cells for CAR T-Cell Therapy.

    Directory of Open Access Journals (Sweden)

    Shou-Hui Du

    Full Text Available Gamma delta (γδ T cells and cytokine-induced killer (CIK cells, which are a heterogeneous population of T lymphocytes and natural killer T (NKT cells, have been separately expanded ex vivo and shown to be capable of targeting and mediating cytotoxicity against various tumor cells in a major histocompatibility complex-unrestricted manner. However, the co-expansion and co-administration of these immune cells have not been explored. In this study we describe an efficient method to expand simultaneously both CIK and Vγ9Vδ2 T cells, termed as CIKZ cells, from human peripheral blood mononuclear cells (PBMCs using Zometa, interferon-gamma (IFN-γ, interleukin 2 (IL-2, anti-CD3 antibody and engineered K562 feeder cells expressing CD64, CD137L and CD86. A 21-day culture of PBMCs with this method yielded nearly 20,000-fold expansion of CIKZ cells with γδ T cells making up over 20% of the expanded population. The expanded CIKZ cells exhibited antitumor cytotoxicity and could be modified to express anti-CD19 chimeric antigen receptor (CAR, anti-CEA CAR, and anti-HER2 CAR to enhance their specificity and cytotoxicity against CD19-, CEA-, or HER2-positive tumor cells. The tumor inhibitory activity of anti-CD19 CAR-modified CIKZ cells was further demonstrated in vivo in a Raji tumor mouse model. The findings herein substantiate the feasibility of co-expanding CIK and γδ cells for adoptive cellular immunotherapy applications such as CAR T-cell therapy against cancer.

  7. CD8 Follicular T Cells Promote B Cell Antibody Class Switch in Autoimmune Disease.

    Science.gov (United States)

    Valentine, Kristen M; Davini, Dan; Lawrence, Travis J; Mullins, Genevieve N; Manansala, Miguel; Al-Kuhlani, Mufadhal; Pinney, James M; Davis, Jason K; Beaudin, Anna E; Sindi, Suzanne S; Gravano, David M; Hoyer, Katrina K

    2018-05-09

    CD8 T cells can play both a protective and pathogenic role in inflammation and autoimmune development. Recent studies have highlighted the ability of CD8 T cells to function as T follicular helper (Tfh) cells in the germinal center in the context of infection. However, whether this phenomenon occurs in autoimmunity and contributes to autoimmune pathogenesis is largely unexplored. In this study, we show that CD8 T cells acquire a CD4 Tfh profile in the absence of functional regulatory T cells in both the IL-2-deficient and scurfy mouse models. Depletion of CD8 T cells mitigates autoimmune pathogenesis in IL-2-deficient mice. CD8 T cells express the B cell follicle-localizing chemokine receptor CXCR5, a principal Tfh transcription factor Bcl6, and the Tfh effector cytokine IL-21. CD8 T cells localize to the B cell follicle, express B cell costimulatory proteins, and promote B cell differentiation and Ab isotype class switching. These data reveal a novel contribution of autoreactive CD8 T cells to autoimmune disease, in part, through CD4 follicular-like differentiation and functionality. Copyright © 2018 by The American Association of Immunologists, Inc.

  8. Mechanisms behind functional avidity maturation in T cells

    DEFF Research Database (Denmark)

    von Essen, Marina Rode; Kongsbak, Martin; Geisler, Carsten

    2012-01-01

    During an immune response antigen-primed B-cells increase their antigen responsiveness by affinity maturation mediated by somatic hypermutation of the genes encoding the antigen-specific B-cell receptor (BCR) and by selection of higher-affinity B cell clones. Unlike the BCR, the T-cell receptor...

  9. Rethinking the role of myeloid-derived suppressor cells in adoptive T-cell therapy for cancer

    Science.gov (United States)

    Arina, Ainhoa

    2014-01-01

    The expansion of cancer-induced myeloid cells is thought to be one of the main obstacles to successful immunotherapy. Nevertheless, in murine tumors undergoing immune-mediated destruction by adoptively transferred T cells, we have recently shown that such cells maintain their immunosuppressive properties. Therefore, adoptive T-cell therapy can, under certain conditions, overcome myeloid cell immunosuppression. PMID:25050213

  10. Increased numbers of preexisting memory CD8 T cells and decreased T-bet expression can restrain terminal differentiation of secondary effector and memory CD8 T cells.

    Science.gov (United States)

    Joshi, Nikhil S; Cui, Weiguo; Dominguez, Claudia X; Chen, Jonathan H; Hand, Timothy W; Kaech, Susan M

    2011-10-15

    Memory CD8 T cells acquire effector memory cell properties after reinfection and may reach terminally differentiated, senescent states ("Hayflick limit") after multiple infections. The signals controlling this process are not well understood, but we found that the degree of secondary effector and memory CD8 T cell differentiation was intimately linked to the amount of T-bet expressed upon reactivation and preexisting memory CD8 T cell number (i.e., primary memory CD8 T cell precursor frequency) present during secondary infection. Compared with naive cells, memory CD8 T cells were predisposed toward terminal effector (TE) cell differentiation because they could immediately respond to IL-12 and induce T-bet, even in the absence of Ag. TE cell formation after secondary (2°) or tertiary infections was dependent on increased T-bet expression because T-bet(+/-) cells were resistant to these phenotypic changes. Larger numbers of preexisting memory CD8 T cells limited the duration of 2° infection and the amount of IL-12 produced, and consequently, this reduced T-bet expression and the proportion of 2° TE CD8 T cells that formed. Together, these data show that over repeated infections, memory CD8 T cell quality and proliferative fitness is not strictly determined by the number of serial encounters with Ag or cell divisions, but is a function of the CD8 T cell differentiation state, which is genetically controlled in a T-bet-dependent manner. This differentiation state can be modulated by preexisting memory CD8 T cell number and the intensity of inflammation during reinfection. These results have important implications for vaccinations involving prime-boost strategies.

  11. c-MPL provides tumor-targeted T-cell receptor-transgenic T cells with costimulation and cytokine signals.

    Science.gov (United States)

    Nishimura, Christopher D; Brenner, Daniel A; Mukherjee, Malini; Hirsch, Rachel A; Ott, Leah; Wu, Meng-Fen; Liu, Hao; Dakhova, Olga; Orange, Jordan S; Brenner, Malcolm K; Lin, Charles Y; Arber, Caroline

    2017-12-21

    Adoptively transferred T-cell receptor (TCR)-engineered T cells depend on host-derived costimulation and cytokine signals for their full and sustained activation. However, in patients with cancer, both signals are frequently impaired. Hence, we developed a novel strategy that combines both essential signals in 1 transgene by expressing the nonlymphoid hematopoietic growth factor receptor c-MPL (myeloproliferative leukemia), the receptor for thrombopoietin (TPO), in T cells. c-MPL signaling activates pathways shared with conventional costimulatory and cytokine receptor signaling. Thus, we hypothesized that host-derived TPO, present in the tumor microenvironment, or pharmacological c-MPL agonists approved by the US Food and Drug Administration could deliver both signals to c-MPL-engineered TCR-transgenic T cells. We found that c-MPL + polyclonal T cells expand and proliferate in response to TPO, and persist longer after adoptive transfer in immunodeficient human TPO-transgenic mice. In TCR-transgenic T cells, c-MPL activation enhances antitumor function, T-cell expansion, and cytokine production and preserves a central memory phenotype. c-MPL signaling also enables sequential tumor cell killing, enhances the formation of effective immune synapses, and improves antileukemic activity in vivo in a leukemia xenograft model. We identify the type 1 interferon pathway as a molecular mechanism by which c-MPL mediates immune stimulation in T cells. In conclusion, we present a novel immunotherapeutic strategy using c-MPL-enhanced transgenic T cells responding to either endogenously produced TPO (a microenvironment factor in hematologic malignancies) or c-MPL-targeted pharmacological agents. © 2017 by The American Society of Hematology.

  12. Differential effects of IL-2 and IL-21 on expansion of the CD4+ CD25+ Foxp3+ T regulatory cells with redundant roles in natural killer cell mediated antibody dependent cellular cytotoxicity in chronic lymphocytic leukemia.

    Science.gov (United States)

    Gowda, Aruna; Ramanunni, Asha; Cheney, Carolyn; Rozewski, Darlene; Kindsvogel, Wayne; Lehman, Amy; Jarjoura, David; Caligiuri, Michael; Byrd, John C; Muthusamy, Natarajan

    2010-01-01

    CD4(+) CD25(+) regulatory T cells are expanded in solid and hematological malignancies including chronic lymphocytic leukemia (CLL). Several cytokines and co-stimulatory molecules are required for generation, survival and maintenance of their suppressive effect. We and others have shown direct cytotoxic effect of the novel common gamma chain cytokine interleukin (IL)-21 on primary B cells from CLL patients. Since members of this family of cytokines are known to exhibit their effects on diverse immune cells, we have examined the effects of IL-21 on CLL patient derived regulatory T cell (Treg) induction, expansion and the inhibitory effect on natural killer cells in vitro. We demonstrate here the expression of IL-21 receptor in CD4(+)CD25(High) regulatory cells from CLL patients. In contrast to IL-2, the IL-21 cytokine failed to mediate expansion of regulatory T cells or induced expression of Foxp3 in CD4(+)CD25(Intermediate) or CD4(+)CD25(Dim/-) T cells in whole blood derived from CLL patients. Interestingly, in contrast to their differential effects on expansion of the CD4(+)CD25(+)Foxp3(+)T cells, IL-2 and IL-21 exhibited a redundant role in Treg mediated suppression of NK cell mediated antibody dependent cytotoxicity function. Given the infusion related toxicities and pro-survival effect of IL-2 in CLL, these studies provide a rationale to explore IL-21 as an alternate gamma chain cytokine in CLL therapy.

  13. An evidence for adhesion-mediated acquisition of acute myeloid leukemic stem cell-like immaturities

    International Nuclear Information System (INIS)

    Funayama, Keiji; Shimane, Miyuki; Nomura, Hitoshi; Asano, Shigetaka

    2010-01-01

    For long-term survival in vitro and in vivo of acute myeloid leukemia cells, their adhesion to bone marrow stromal cells is indispensable. However, it is still unknown if these events are uniquely induced by the leukemic stem cells. Here we show that TF-1 human leukemia cells, once they have formed a cobblestone area by adhering to mouse bone marrow-derived MS-5 cells, can acquire some leukemic stem cell like properties in association with a change in the CD44 isoform-expression pattern and with an increase in a set of related microRNAs. These findings strongly suggest that at least some leukemia cells can acquire leukemic stem cell like properties in an adhesion-mediated stochastic fashion.

  14. An evidence for adhesion-mediated acquisition of acute myeloid leukemic stem cell-like immaturities

    Energy Technology Data Exchange (ETDEWEB)

    Funayama, Keiji; Shimane, Miyuki; Nomura, Hitoshi [Department of Integrative Bioscience and Biomedical Engineering, Waseda University, 4-3-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555 (Japan); Asano, Shigetaka, E-mail: asgtkmd@waseda.jp [Department of Integrative Bioscience and Biomedical Engineering, Waseda University, 4-3-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555 (Japan)

    2010-02-12

    For long-term survival in vitro and in vivo of acute myeloid leukemia cells, their adhesion to bone marrow stromal cells is indispensable. However, it is still unknown if these events are uniquely induced by the leukemic stem cells. Here we show that TF-1 human leukemia cells, once they have formed a cobblestone area by adhering to mouse bone marrow-derived MS-5 cells, can acquire some leukemic stem cell like properties in association with a change in the CD44 isoform-expression pattern and with an increase in a set of related microRNAs. These findings strongly suggest that at least some leukemia cells can acquire leukemic stem cell like properties in an adhesion-mediated stochastic fashion.

  15. Primed T cell responses to chemokines are regulated by the immunoglobulin-like molecule CD31.

    Directory of Open Access Journals (Sweden)

    Madhav Kishore

    Full Text Available CD31, an immunoglobulin-like molecule expressed by leukocytes and endothelial cells, is thought to contribute to the physiological regulation T cell homeostasis due to the presence of two immunotyrosine-based inhibitory motifs in its cytoplasmic tail. Indeed, loss of CD31 expression leads to uncontrolled T cell-mediated inflammation in a variety of experimental models of disease and certain CD31 polymorphisms correlate with increased disease severity in human graft-versus-host disease and atherosclerosis. The molecular mechanisms underlying CD31-mediated regulation of T cell responses have not yet been clarified. We here show that CD31-mediated signals attenuate T cell chemokinesis both in vitro and in vivo. This effect selectively affects activated/memory T lymphocytes, in which CD31 is clustered on the cell membrane where it segregates to the leading edge. We provide evidence that this molecular segregation, which does not occur in naïve T lymphocytes, might lead to cis-CD31 engagement on the same membrane and subsequent interference with the chemokine-induced PI3K/Akt signalling pathway. We propose that CD31-mediated modulation of memory T cell chemokinesis is a key mechanism by which this molecule contributes to the homeostatic regulation of effector T cell immunity.

  16. Highly active microbial phosphoantigen induces rapid yet sustained MEK/Erk- and PI-3K/Akt-mediated signal transduction in anti-tumor human gammadelta T-cells.

    Directory of Open Access Journals (Sweden)

    Daniel V Correia

    Full Text Available BACKGROUND: The unique responsiveness of Vgamma9Vdelta2 T-cells, the major gammadelta subset of human peripheral blood, to non-peptidic prenyl pyrophosphate antigens constitutes the basis of current gammadelta T-cell-based cancer immunotherapy strategies. However, the molecular mechanisms responsible for phosphoantigen-mediated activation of human gammadelta T-cells remain unclear. In particular, previous reports have described a very slow kinetics of activation of T-cell receptor (TCR-associated signal transduction pathways by isopentenyl pyrophosphate and bromohydrin pyrophosphate, seemingly incompatible with direct binding of these antigens to the Vgamma9Vdelta2 TCR. Here we have studied the most potent natural phosphoantigen yet identified, (E-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMB-PP, produced by Eubacteria and Protozoa, and examined its gammadelta T-cell activation and anti-tumor properties. METHODOLOGY/PRINCIPAL FINDINGS: We have performed a comparative study between HMB-PP and the anti-CD3epsilon monoclonal antibody OKT3, used as a reference inducer of bona fide TCR signaling, and followed multiple cellular and molecular gammadelta T-cell activation events. We show that HMB-PP activates MEK/Erk and PI-3K/Akt pathways as rapidly as OKT3, and induces an almost identical transcriptional profile in Vgamma9(+ T-cells. Moreover, MEK/Erk and PI-3K/Akt activities are indispensable for the cellular effects of HMB-PP, including gammadelta T-cell activation, proliferation and anti-tumor cytotoxicity, which are also abolished upon antibody blockade of the Vgamma9(+ TCR Surprisingly, HMB-PP treatment does not induce down-modulation of surface TCR levels, and thereby sustains gammadelta T-cell activation upon re-stimulation. This ultimately translates in potent human gammadelta T-cell anti-tumor function both in vitro and in vivo upon transplantation of human leukemia cells into lymphopenic mice, CONCLUSIONS/SIGNIFICANCE: The development of

  17. Dysregulated cytokine expression by CD4+ T cells from post-septic mice modulates both Th1 and Th2-mediated granulomatous lung inflammation.

    Directory of Open Access Journals (Sweden)

    William F Carson

    Full Text Available Previous epidemiological studies in humans and experimental studies in animals indicate that survivors of severe sepsis exhibit deficiencies in the activation and effector function of immune cells. In particular, CD4+ T lymphocytes can exhibit reduced proliferative capacity and improper cytokine responses following sepsis. To further investigate the cell-intrinsic defects of CD4+ T cells following sepsis, splenic CD4+ T cells from sham surgery and post-septic mice were transferred into lymphopenic mice. These recipient mice were then subjected to both TH1-(purified protein derivative and TH2-(Schistosoma mansoni egg antigen driven models of granulomatous lung inflammation. Post-septic CD4+ T cells mediated smaller TH1 and larger TH2 lung granulomas as compared to mice receiving CD4+ T cells from sham surgery donors. However, cytokine production by lymph node cells in antigen restimulation assays indicated increased pan-specific cytokine expression by post-septic CD4+ T cell recipient mice in both TH1 and TH2 granuloma models. These include increased production of T(H2 cytokines in TH1 inflammation, and increased production of T(H1 cytokines in TH2 inflammation. These results suggest that cell-intrinsic defects in CD4+ T cell effector function can have deleterious effects on inflammatory processes post-sepsis, due to a defect in the proper regulation of TH-specific cytokine expression.

  18. Hemophagocytic lymphohistiocytosis secondary to T-cell/histiocyte-rich large B-cell lymphoma

    Directory of Open Access Journals (Sweden)

    Katherine Devitt

    2014-01-01

    Full Text Available Hemophagocytic lymphohistiocytosis (HLH is a life-threatening clinical syndrome characterized by dysregulation of the immune system. Impaired function of cytotoxic T cells and natural killer cells is often seen, and T-cell malignancies represent most cases of lymphoma-associated HLH. HLH associated with B-cell lymphoma is rare. We describe a case of a 30-year-old man who presented with fever, splenomegaly, and hyperferritinemia. Bone marrow biopsy revealed T-cell/histiocyte-rich large B-cell lymphoma, a rare, aggressive B-cell malignancy. This case highlights the interplay between a pro-inflammatory cytokine microenvironment and tumor-mediated immune suppression, and addresses the importance of accurately diagnosing these entities for appropriate clinical management.

  19. Hemophagocytic lymphohistiocytosis secondary to T-cell/histiocyte-rich large B-cell lymphoma.

    Science.gov (United States)

    Devitt, Katherine; Cerny, Jan; Switzer, Bradley; Ramanathan, Muthalagu; Nath, Rajneesh; Yu, Hongbo; Woda, Bruce A; Chen, Benjamin J

    2014-01-01

    Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening clinical syndrome characterized by dysregulation of the immune system. Impaired function of cytotoxic T cells and natural killer cells is often seen, and T-cell malignancies represent most cases of lymphoma-associated HLH. HLH associated with B-cell lymphoma is rare. We describe a case of a 30-year-old man who presented with fever, splenomegaly, and hyperferritinemia. Bone marrow biopsy revealed T-cell/histiocyte-rich large B-cell lymphoma, a rare, aggressive B-cell malignancy. This case highlights the interplay between a pro-inflammatory cytokine microenvironment and tumor-mediated immune suppression, and addresses the importance of accurately diagnosing these entities for appropriate clinical management.

  20. The PDL1-PD1 Axis Converts Human Th1 Cells Into Regulatory T Cells

    Science.gov (United States)

    Amarnath, Shoba; Mangus, Courtney W.; Wang, James C.M.; Wei, Fang; He, Alice; Kapoor, Veena; Foley, Jason E.; Massey, Paul R.; Felizardo, Tania C.; Riley, James L.; Levine, Bruce L.; June, Carl H.; Medin, Jeffrey A.; Fowler, Daniel H.

    2011-01-01

    Immune surveillance by T helper type 1 (Th1) cells is critical for the host response to tumors and infection, but also contributes to autoimmunity and graft-versus-host disease (GvHD) after transplantation. The inhibitory molecule programmed death ligand-1 (PDL1) has been shown to anergize human Th1 cells, but other mechanisms of PDL1-mediated Th1 inhibition such as the conversion of Th1 cells to a regulatory phenotype have not been well characterized. We hypothesized that PDL1 may cause Th1 cells to manifest differentiation plasticity. Conventional T cells or irradiated K562 myeloid tumor cells overexpressing PDL1 converted TBET+ Th1 cells into FOXP3+ regulatory T cells (TREGS) in vivo, thereby preventing human-into-mouse xenogeneic GvHD (xGvHD). Either blocking PD1 expression on Th1 cells by siRNA targeting or abrogation of PD1 signaling by SHP1/2 pharmacologic inhibition stabilized Th1 cell differentiation during PDL1 challenge and restored the capacity of Th1 cells to mediate lethal xGVHD. PD1 signaling therefore induces human Th1 cells to manifest in vivo plasticity, resulting in a TREG phenotype that severely impairs cell-mediated immunity. Converting human Th1 cells to a regulatory phenotype with PD1 signaling provides a potential way to block GvHD after transplantation. Moreover, because this conversion can be prevented by blocking PD1 expression or pharmacologically inhibiting SHP1/2, this pathway provides a new therapeutic direction for enhancing T cell immunity to cancer and infection. PMID:22133721

  1. CD4/CD8/Dendritic cell complexes in the spleen: CD8+ T cells can directly bind CD4+ T cells and modulate their response

    Science.gov (United States)

    Barinov, Aleksandr; Galgano, Alessia; Krenn, Gerald; Tanchot, Corinne; Vasseur, Florence

    2017-01-01

    CD4+ T cell help to CD8+ T cell responses requires that CD4+ and CD8+ T cells interact with the same antigen presenting dendritic cell (Ag+DC), but it remains controversial whether helper signals are delivered indirectly through a licensed DC and/or involve direct CD4+/CD8+ T cell contacts and/or the formation of ternary complexes. We here describe the first in vivo imaging of the intact spleen, aiming to evaluate the first interactions between antigen-specific CD4+, CD8+ T cells and Ag+DCs. We show that in contrast to CD4+ T cells which form transient contacts with Ag+DC, CD8+ T cells form immediate stable contacts and activate the Ag+DC, acquire fragments of the DC membranes by trogocytosis, leading to their acquisition of some of the DC properties. They express MHC class II, and become able to present the specific Marilyn peptide to naïve Marilyn CD4+ T cells, inducing their extensive division. In vivo, these CD8+ T cells form direct stable contacts with motile naïve CD4+ T cells, recruiting them to Ag+DC binding and to the formation of ternary complexes, where CD4+ and CD8+ T cells interact with the DC and with one another. The presence of CD8+ T cells during in vivo immune responses leads to the early activation and up-regulation of multiple functions by CD4+ T lymphocytes. Thus, while CD4+ T cell help is important to CD8+ T cell responses, CD8+ T cells can interact directly with naïve CD4+ T cells impacting their recruitment and differentiation. PMID:28686740

  2. CYP2E1-dependent and leptin-mediated hepatic CD57 expression on CD8 + T cells aid progression of environment-linked nonalcoholic steatohepatitis

    International Nuclear Information System (INIS)

    Seth, Ratanesh Kumar; Das, Suvarthi; Kumar, Ashutosh; Chanda, Anindya; Kadiiska, Maria B.; Michelotti, Gregory; Manautou, Jose; Diehl, Anna Mae; Chatterjee, Saurabh

    2014-01-01

    Environmental toxins induce a novel CYP2E1/leptin signaling axis in liver. This in turn activates a poorly characterized innate immune response that contributes to nonalcoholic steatohepatitis (NASH) progression. To identify the relevant subsets of T-lymphocytes in CYP2E1-dependent, environment-linked NASH, we utilized a model of diet induced obese (DIO) mice that are chronically exposed to bromodichloromethane. Mice deficient in CYP2E1, leptin (ob/ob mice), or both T and B cells (Pfp/Rag2 double knockout (KO) mice) were used to delineate the role of each of these factors in metabolic oxidative stress-induced T cell activation. Results revealed that elevated levels of lipid peroxidation, tyrosyl radical formation, mitochondrial tyrosine nitration and hepatic leptin as a consequence of metabolic oxidative stress caused increased levels of hepatic CD57, a marker of peripheral blood lymphocytes including NKT cells. CD8 + CD57 + cytotoxic T cells but not CD4 + CD57 + cells were significantly decreased in mice lacking CYP2E1 and leptin. There was a significant increase in the levels of T cell cytokines IL-2, IL-1β, and IFN-γ in bromodichloromethane exposed DIO mice but not in mice that lacked CYP2E1, leptin or T and B cells. Apoptosis as evidenced by TUNEL assay and levels of cleaved caspase-3 was significantly lower in leptin and Pfp/Rag2 KO mice and highly correlated with protection from NASH. The results described above suggest that higher levels of oxidative stress-induced leptin mediated CD8 + CD57 + T cells play an important role in the development of NASH. It also provides a novel insight of immune dysregulation and may be a key biomarker in NASH. - Highlights: • Metabolic oxidative stress caused increased levels of hepatic CD57 expression. • CD8+ CD57+ cytotoxic T cells were decreased in mice lacking CYP2E1 and leptin. • There was a significant increase in T cell cytokines in toxin-treated mice. • Apoptosis was significantly lower in leptin and Pfp

  3. CYP2E1-dependent and leptin-mediated hepatic CD57 expression on CD8 + T cells aid progression of environment-linked nonalcoholic steatohepatitis

    Energy Technology Data Exchange (ETDEWEB)

    Seth, Ratanesh Kumar; Das, Suvarthi [Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208 (United States); Kumar, Ashutosh [Free Radical Metabolism Group, Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 (United States); Chanda, Anindya [Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208 (United States); Kadiiska, Maria B. [Free Radical Metabolism Group, Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 (United States); Michelotti, Gregory [Division of Gastroenterology, Duke University, Durham, NC 27707 (United States); Manautou, Jose [Dept. of Pharmaceutical Sciences, University of Connecticut, Storrs, CT 06269-3092 (United States); Diehl, Anna Mae [Division of Gastroenterology, Duke University, Durham, NC 27707 (United States); Chatterjee, Saurabh, E-mail: schatt@mailbox.sc.edu [Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208 (United States)

    2014-01-01

    Environmental toxins induce a novel CYP2E1/leptin signaling axis in liver. This in turn activates a poorly characterized innate immune response that contributes to nonalcoholic steatohepatitis (NASH) progression. To identify the relevant subsets of T-lymphocytes in CYP2E1-dependent, environment-linked NASH, we utilized a model of diet induced obese (DIO) mice that are chronically exposed to bromodichloromethane. Mice deficient in CYP2E1, leptin (ob/ob mice), or both T and B cells (Pfp/Rag2 double knockout (KO) mice) were used to delineate the role of each of these factors in metabolic oxidative stress-induced T cell activation. Results revealed that elevated levels of lipid peroxidation, tyrosyl radical formation, mitochondrial tyrosine nitration and hepatic leptin as a consequence of metabolic oxidative stress caused increased levels of hepatic CD57, a marker of peripheral blood lymphocytes including NKT cells. CD8 + CD57 + cytotoxic T cells but not CD4 + CD57 + cells were significantly decreased in mice lacking CYP2E1 and leptin. There was a significant increase in the levels of T cell cytokines IL-2, IL-1β, and IFN-γ in bromodichloromethane exposed DIO mice but not in mice that lacked CYP2E1, leptin or T and B cells. Apoptosis as evidenced by TUNEL assay and levels of cleaved caspase-3 was significantly lower in leptin and Pfp/Rag2 KO mice and highly correlated with protection from NASH. The results described above suggest that higher levels of oxidative stress-induced leptin mediated CD8 + CD57 + T cells play an important role in the development of NASH. It also provides a novel insight of immune dysregulation and may be a key biomarker in NASH. - Highlights: • Metabolic oxidative stress caused increased levels of hepatic CD57 expression. • CD8+ CD57+ cytotoxic T cells were decreased in mice lacking CYP2E1 and leptin. • There was a significant increase in T cell cytokines in toxin-treated mice. • Apoptosis was significantly lower in leptin and Pfp

  4. Enhanced killing of chordoma cells by antibody-dependent cell-mediated cytotoxicity employing the novel anti-PD-L1 antibody avelumab.

    Science.gov (United States)

    Fujii, Rika; Friedman, Eitan R; Richards, Jacob; Tsang, Kwong Y; Heery, Christopher R; Schlom, Jeffrey; Hodge, James W

    2016-06-07

    Chordoma, a rare bone tumor derived from the notochord, has been shown to be resistant to conventional therapies. Checkpoint inhibition has shown great promise in immune-mediated therapy of diverse cancers. The anti-PD-L1 mAb avelumab is unique among checkpoint inhibitors in that it is a fully human IgG1 capable of mediating antibody-dependent cell-mediated cytotoxicity (ADCC) of PD-L1-expressing tumor cells. Here, we investigated avelumab as a potential therapy for chordoma. We examined 4 chordoma cell lines, first for expression of PD-L1, and in vitro for ADCC killing using NK cells and avelumab. PD-L1 expression was markedly upregulated by IFN-γ in all 4 chordoma cell lines, which significantly increased sensitivity to ADCC. Brachyury is a transcription factor that is uniformly expressed in chordoma. Clinical trials are ongoing in which chordoma patients are treated with brachyury-specific vaccines. Co-incubating chordoma cells with brachyury-specific CD8+ T cells resulted in significant upregulation of PD-L1 on the tumor cells, mediated by the CD8+ T cells' IFN-γ production, and increased sensitivity of chordoma cells to avelumab-mediated ADCC. Residential cancer stem cell subpopulations of chordoma cells were also killed by avelumab-mediated ADCC to the same degree as non-cancer stem cell populations. These findings suggest that as a monotherapy for chordoma, avelumab may enable endogenous NK cells, while in combination with T-cell immunotherapy, such as a vaccine, avelumab may enhance NK-cell killing of chordoma cells via ADCC.

  5. The adaptor protein SAP directly associates with PECAM-1 and regulates PECAM-1-mediated-cell adhesion in T-like cell lines.

    Science.gov (United States)

    Proust, Richard; Crouin, Catherine; Gandji, Leslie Yewakon; Bertoglio, Jacques; Gesbert, Franck

    2014-04-01

    SAP is a small cytosolic adaptor protein expressed in hematopoietic lineages whose main function is to regulate intracellular signaling pathways induced by the triggering of members of the SLAM receptor family. In this paper, we have identified the adhesion molecule PECAM-1 as a new partner for SAP in a conditional yeast two-hybrid screen. PECAM-1 is an immunoglobulin-like molecule expressed by endothelial cells and leukocytes, which possesses both pro- and anti-inflammatory properties. However, little is known about PECAM-1 functions in T cells. We show that SAP directly and specifically interacts with the cytosolic tyrosine 686 of PECAM-1. We generated different T-like cell lines in which SAP or PECAM-1 are expressed or down modulated and we demonstrate that a diminished SAP expression correlates with a diminished PECAM-1-mediated adhesion. Although SAP has mainly been shown to associate with SLAM receptors, we evidence here that SAP is a new actor downstream of PECAM-1. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Divergent Roles of Interferon-γ and Innate Lymphoid Cells in Innate and Adaptive Immune Cell-Mediated Intestinal Inflammation.

    Science.gov (United States)

    Brasseit, Jennifer; Kwong Chung, Cheong K C; Noti, Mario; Zysset, Daniel; Hoheisel-Dickgreber, Nina; Genitsch, Vera; Corazza, Nadia; Mueller, Christoph

    2018-01-01

    Aberrant interferon gamma (IFNγ) expression is associated with the pathogenesis of numerous autoimmune- and inflammatory disorders, including inflammatory bowel diseases (IBD). However, the requirement of IFNγ for the pathogenesis of chronic intestinal inflammation remains controversial. The aim of this study was thus to investigate the role of IFNγ in experimental mouse models of innate and adaptive immune cell-mediated intestinal inflammation using genetically and microbiota-stabilized hosts. While we find that IFNγ drives acute intestinal inflammation in the anti-CD40 colitis model in an innate lymphoid cell (ILC)-dependent manner, IFNγ secreted by both transferred CD4 T cells and/or cells of the lymphopenic Rag1 -/- recipient mice was dispensable for CD4 T cell-mediated colitis. In the absence of IFNγ, intestinal inflammation in CD4 T cell recipient mice was associated with enhanced IL17 responses; consequently, targeting IL17 signaling in IFNγ-deficient mice reduced T cell-mediated colitis. Intriguingly, in contrast to the anti-CD40 model of colitis, depletion of ILC in the Rag1 -/- recipients of colitogenic CD4 T cells did not prevent induction of colonic inflammation. Together, our findings demonstrate that IFNγ represents an essential, or a redundant, pro-inflammatory cytokine for the induction of intestinal inflammation, depending on the experimental mouse model used and on the nature of the critical disease inducing immune cell populations involved.

  7. Group 3 innate lymphoid cells mediate intestinal selection of commensal bacteria-specific CD4+ T cells

    Science.gov (United States)

    Hepworth, Matthew R.; Fung, Thomas C.; Masur, Samuel H.; Kelsen, Judith R.; McConnell, Fiona M.; Dubrot, Juan; Withers, David R.; Hugues, Stephanie; Farrar, Michael A.; Reith, Walter; Eberl, Gerard; Baldassano, Robert N.; Laufer, Terri M.; Elson, Charles O.; Sonnenberg, Gregory F.

    2015-01-01

    Inflammatory CD4+ T cell responses to self or commensal bacteria underlie the pathogenesis of autoimmunity and inflammatory bowel disease (IBD), respectively. While selection of self-specific T cells in the thymus limits responses to tissue antigens, the mechanisms that control selection of commensal bacteria-specific T cells remain poorly understood. Here we demonstrate that group 3 innate lymphoid cell (ILC3)-intrinsic expression of major histocompatibility complex class II (MHCII) is regulated similarly to thymic epithelial cells, and that MHCII+ ILC3s directly induce cell death of activated commensal bacteria-specific T cells. Further, MHCII on human colonic ILC3s was reduced in pediatric IBD patients. Collectively, these results define a selection pathway for commensal bacteria-specific CD4+ T cells in the intestine, and suggest that this process is dysregulated in human IBD. PMID:25908663

  8. Circumsporozoite Protein-Specific Kd-Restricted CD8+ T Cells Mediate Protective Antimalaria Immunity in Sporozoite-Immunized MHC-I-Kd Transgenic Mice

    Directory of Open Access Journals (Sweden)

    Jing Huang

    2014-01-01

    Full Text Available Although the roles of CD8+ T cells and a major preerythrocytic antigen, the circumsporozoite (CS protein, in contributing protective antimalaria immunity induced by radiation-attenuated sporozoites, have been shown by a number of studies, the extent to which these players contribute to antimalaria immunity is still unknown. To address this question, we have generated C57BL/6 (B6 transgenic (Tg mice, expressing Kd molecules under the MHC-I promoter, called MHC-I-Kd-Tg mice. In this study, we first determined that a single immunizing dose of IrPySpz induced a significant level of antimalaria protective immunity in MHC-I-Kd-Tg mice but not in B6 mice. Then, by depleting various T-cell subsets in vivo, we determined that CD8+ T cells are the main mediator of the protective immunity induced by IrPySpz. Furthermore, when we immunized (MHC-I-Kd-Tg × CS-Tg F1 mice with IrPySpz after crossing MHC-I-Kd-Tg mice with PyCS-transgenic mice (CS-Tg, which are unable to mount PyCS-specific immunity, we found that IrPySpz immunization failed to induce protective antimalaria immunity in (MHC-I-Kd-Tg × CS-Tg F1 mice, thus indicating the absence of PyCS antigen-dependent immunity in these mice. These results indicate that protective antimalaria immunity induced by IrPySpz in MHC-I-Kd-Tg mice is mediated by CS protein-specific, Kd-restricted CD8+ T cells.

  9. Cholesterol Accumulation in Dendritic Cells Links the Inflammasome to Acquired Immunity.

    Science.gov (United States)

    Westerterp, Marit; Gautier, Emmanuel L; Ganda, Anjali; Molusky, Matthew M; Wang, Wei; Fotakis, Panagiotis; Wang, Nan; Randolph, Gwendalyn J; D'Agati, Vivette D; Yvan-Charvet, Laurent; Tall, Alan R

    2017-06-06

    Autoimmune diseases such as systemic lupus erythematosus (SLE) are associated with increased cardiovascular disease and reduced plasma high-density lipoprotein (HDL) levels. HDL mediates cholesterol efflux from immune cells via the ATP binding cassette transporters A1 and G1 (ABCA1/G1). The significance of impaired cholesterol efflux pathways in autoimmunity is unknown. We observed that Abca1/g1-deficient mice develop enlarged lymph nodes (LNs) and glomerulonephritis suggestive of SLE. This lupus-like phenotype was recapitulated in mice with knockouts of Abca1/g1 in dendritic cells (DCs), but not in macrophages or T cells. DC-Abca1/g1 deficiency increased LN and splenic CD11b + DCs, which displayed cholesterol accumulation and inflammasome activation, increased cell surface levels of the granulocyte macrophage-colony stimulating factor receptor, and enhanced inflammatory cytokine secretion. Consequently, DC-Abca1/g1 deficiency enhanced T cell activation and T h 1 and T h 17 cell polarization. Nlrp3 inflammasome deficiency diminished the enlarged LNs and enhanced T h 1 cell polarization. These findings identify an essential role of DC cholesterol efflux pathways in maintaining immune tolerance. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. MUC1 (CD227) interacts with lck tyrosine kinase in Jurkat lymphoma cells and normal T cells.

    Science.gov (United States)

    Mukherjee, P; Tinder, T L; Basu, G D; Gendler, S J

    2005-01-01

    MUC1 (CD227) is a large transmembrane epithelial mucin glycoprotein, which is aberrantly overexpressed in most adenocarcinomas and is a target for immune therapy for epithelial tumors. Recently, MUC1 has been detected in a variety of hematopoietic cell malignancies including T and B cell lymphomas and myelomas; however, its function in these cells is not clearly defined. Using the Jurkat T cell lymphoma cell line and normal human T cells, we demonstrate that MUC1 is not only expressed in these cells but is also phosphorylated upon T cell receptor (TCR) ligation and associates with the Src-related T cell tyrosine kinase, p56lck. Upon TCR-mediated activation of Jurkat cells, MUC1 is found in the low-density membrane fractions, where linker of T cell activation is contained. Abrogation of MUC1 expression in Jurkat cells by MUC1-specific small interfering RNA resulted in defects in TCR-mediated downstream signaling events associated with T cell activation. These include reduction in Ca2+ influx and extracellular signal-regulated kinase 1/2 phosphorylation, leading to a decrease in CD69 expression, proliferation, and interleukin-2 production. These results suggest a regulatory role of MUC1 in modulating proximal signal transduction events through its interaction with proteins of the activation complex.

  11. Analysis of the paired TCR α- and β-chains of single human T cells.

    Directory of Open Access Journals (Sweden)

    Song-Min Kim

    Full Text Available Analysis of the paired i.e. matching TCR α- and β-chain rearrangements of single human T cells is required for a precise investigation of clonal diversity, tissue distribution and specificity of protective and pathologic T-cell mediated immune responses. Here we describe a multiplex RT-PCR based technology, which for the first time allows for an unbiased analysis of the complete sequences of both α- and β-chains of TCR from single T cells. We validated our technology by the analysis of the pathologic T-cell infiltrates from tissue lesions of two T-cell mediated autoimmune diseases, psoriasis vulgaris (PV and multiple sclerosis (MS. In both disorders we could detect various T cell clones as defined by multiple T cells with identical α- and β-chain rearrangements distributed across the tissue lesions. In PV, single cell TCR analysis of lesional T cells identified clonal CD8(+ T cell expansions that predominated in the epidermis of psoriatic plaques. An MS brain lesion contained two dominant CD8(+ T-cell clones that extended over the white and grey matter and meninges. In both diseases several clonally expanded T cells carried dual TCRs composed of one Vβ and two different Vα-chain rearrangements. These results show that our technology is an efficient instrument to analyse αβ-T cell responses with single cell resolution in man. It should facilitate essential new insights into the mechanisms of protective and pathologic immunity in many human T-cell mediated conditions and allow for resurrecting functional TCRs from any αβ-T cell of choice that can be used for investigating their specificity.

  12. Asthma and gender impact accumulation of T cell subtypes

    Directory of Open Access Journals (Sweden)

    Peters Stephen P

    2010-07-01

    Full Text Available Abstract Background The "Th2 hypothesis for asthma" asserts that an increased ratio of Th2:Th1 cytokine production plays an important pathogenic role in asthma. Although widely embraced, the hypothesis has been challenged by various empirical observations and has been described as overly simplistic. We sought to establish whether CD3+CD28-mediated and antigen-independent accumulation of type 1 and type 2 T cells differs significantly between nonasthmatic and asthmatic populations. Methods An ex vivo system was used to characterize the regulation of IFN-γ-producing (type 1 and IL-13-producing (type 2 T cell accumulation in response to CD3+CD28 and IL-2 stimulation by flow cytometry. Results IL-13-producing T cells increased in greater numbers in response to antigen-independent stimulation in peripheral blood lymphocytes from female atopic asthmatic subjects compared with male asthmatics and both male and female atopic non-asthmatic subjects. IFN-γ+ T cells increased in greater numbers in response to either antigen-independent or CD3+CD28-mediated stimulation in peripheral blood lymphocytes from atopic asthmatic subjects compared to non-asthmatic subjects, regardless of gender. Conclusions We demonstrate that T cells from asthmatics are programmed for increased accumulation of both type 2 and type 1 T cells. Gender had a profound effect on the regulation of type 2 T cells, thus providing a mechanism for the higher frequency of adult asthma in females.

  13. Thiol dependent NF-κB suppression and inhibition of T-cell mediated adaptive immune responses by a naturally occurring steroidal lactone Withaferin A

    Energy Technology Data Exchange (ETDEWEB)

    Gambhir, Lokesh; Checker, Rahul; Sharma, Deepak; Thoh, M. [Radiation Biology & Health Sciences Division, Bio-science Group, Bhabha Atomic Research Centre, Mumbai (India); Patil, Anand [Advanced Centre for Treatment Research and Education in Cancer, Kharghar, Navi Mumbai (India); Degani, M. [Institute of Chemical Technology, Matunga, Mumbai (India); Gota, Vikram [Advanced Centre for Treatment Research and Education in Cancer, Kharghar, Navi Mumbai (India); Sandur, Santosh K., E-mail: sskumar@barc.gov.in [Radiation Biology & Health Sciences Division, Bio-science Group, Bhabha Atomic Research Centre, Mumbai (India)

    2015-12-01

    Withaferin A (WA), a steroidal lactone isolated from ayurvedic medicinal plant Withania somnifera, was shown to inhibit tumor growth by inducing oxidative stress and suppressing NF-κB pathway. However, its effect on T-cell mediated adaptive immune responses and the underlying mechanism has not been investigated. Since both T-cell responses and NF-κB pathway are known to be redox sensitive, the present study was undertaken to elucidate the effect of WA on adaptive immune responses in vitro and in vivo. WA inhibited mitogen induced T-cell and B-cell proliferation in vitro without inducing any cell death. It inhibited upregulation of T-cell (CD25, CD69, CD71 and CD54) and B-cell (CD80, CD86 and MHC-II) activation markers and secretion of Th1 and Th2 cytokines. WA induced oxidative stress by increasing the basal ROS levels and the immunosuppressive effects of WA were abrogated only by thiol anti-oxidants. The redox modulatory effects of WA in T-cells were attributed to its ability to directly interact with free thiols. WA inhibited NF-κB nuclear translocation in lymphocytes and prevented the direct binding of nuclear NF-κB to its consensus sequence. MALDI-TOF analysis using a synthetic NF-κB-p50 peptide containing Cys-62 residue suggested that WA can modify the cysteine residue of NF-κB. The pharmacokinetic studies for WA were also carried out and in vivo efficacy of WA was studied using mouse model of Graft-versus-host disease. In conclusion, WA is a potent inhibitor of T-cell responses and acts via a novel thiol dependent mechanism and inhibition of NF-κB pathway. - Highlights:: • Withaferin A (WA) inhibited T-cell and B-cell mediated immune responses. • WA increased basal ROS levels in lymphocytes. • WA directly interacted with GSH as studied using spectrophotometry and HPLC. • WA inhibited NF-κB nuclear translocation and binding of nuclear NF-κB to DNA. • WA inhibited induction of the graft-versus-host disease in mice.

  14. Membranes of activated CD4+ T cells expressing T cell receptor (TcR) alpha beta or TcR gamma delta induce IgE synthesis by human B cells in the presence of interleukin-4

    NARCIS (Netherlands)

    Gascan, H.; Aversa, G. G.; Gauchat, J. F.; van Vlasselaer, P.; Roncarolo, M. G.; Yssel, H.; Kehry, M.; Spits, H.; de Vries, J. E.

    1992-01-01

    In the present study it is demonstrated that human B cells can be induced to switch to IgE production following a contact-mediated signal provided by activated T cell receptor (TcR) gamma delta+, CD4+ and TcR alpha beta+, CD4+ T cell clones and interleukin (IL)-4. The signal provided by these T cell

  15. BMI-1 Mediates Estrogen-Deficiency-Induced Bone Loss by Inhibiting Reactive Oxygen Species Accumulation and T Cell Activation.

    Science.gov (United States)

    Li, Jinbo; Wang, Qian; Yang, Renlei; Zhang, Jiaqi; Li, Xing; Zhou, Xichao; Miao, Dengshun

    2017-05-01

    Previous studies have shown that estrogen regulates bone homeostasis through regulatory effects on oxidative stress. However, it is unclear how estrogen deficiency triggers reactive oxygen species (ROS) accumulation. Recent studies provide evidence that the B lymphoma Mo-MLV insertion region 1 (BMI-1) plays a critical role in protection against oxidative stress and that this gene is directly regulated by estrogen via estrogen receptor (ER) at the transcriptional level. In this study, ovariectomized mice were given drinking water with/without antioxidant N-acetyl-cysteine (NAC, 1 mg/mL) supplementation, and compared with each other and with sham mice. Results showed that ovariectomy resulted in bone loss with increased osteoclast surface, increased ROS levels, T cell activation, and increased TNF and RANKL levels in serum and in CD4 T cells; NAC supplementation largely prevented these alterations. BMI-1 expression levels were dramatically downregulated in CD4 T cells from ovariectomized mice. We supplemented drinking water to BMI-1-deficient mice with/without NAC and compared them with each other and with wild-type (WT) mice. We found that BMI-1 deficiency mimicked alterations observed in ovariectomy whereas NAC supplementation reversed all alterations induced by BMI-1 deficiency. Because T cells are critical in mediating ovariectomy-induced bone loss, we further assessed whether BMI-1 overexpression in lymphocytes can protect against estrogen deficiency-induced osteoclastogenesis and bone loss by inhibiting oxidative stress, T cell activation, and RANKL production. When WT and Eμ-BMI-1 transgenic mice with BMI-1 specifically overexpressed in lymphocytes were ovariectomized and compared with each other and with WT sham mice, we found that BMI-1 overexpression in lymphocytes clearly reversed all alterations induced by ovariectomy. Results from this study indicate that estrogen deficiency downregulates BMI-1 and subsequently increases ROS, T cell activation, and

  16. Plumbagin exerts an immunosuppressive effect on human T-cell acute lymphoblastic leukemia MOLT-4 cells

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Kyoung Jun; Lee, Yura [Department of Biomedical Laboratory Science, Daejeon 34824 (Korea, Republic of); Kim, Soon Ae [Department of Pharmacology, School of Medicine, Daejeon 34824 (Korea, Republic of); Kim, Jiyeon, E-mail: yeon@eulji.ac.kr [Department of Biomedical Laboratory Science, Daejeon 34824 (Korea, Republic of)

    2016-04-22

    Of the hematological disorders typified by poor prognoses and survival rates, T-cell acute lymphoblastic leukemia (T-ALL) is one of the most commonly diagnosed. Despite the development of new therapeutic agents, the treatment options for this cancer remain limited. In this manuscript, we investigated the anti-proliferative effects of plumbagin, mediated by the activation of mitogen-activated protein kinase (MAPK) pathways, and inhibition of NF-κB signaling; the human T-ALL MOLT-4 cell line was used as our experimental system. Plumbagin is a natural, plant derived compound, which exerts an anti-proliferative activity against many types of human cancer. Our experiments confirm that plumbagin induces a caspase-dependent apoptosis of MOLT-4 cells, with no significant cytotoxicity seen for normal peripheral blood mononuclear cells (PBMCs). Plumbagin also inhibited LPS-induced phosphorylation of p65, and the transcription of NF-κB target genes. Our results now show that plumbagin is a potent inhibitor of the NF-κB signaling pathway, and suppressor of T-ALL cell proliferation. - Highlights: • Plumbagin induces caspase-dependent apoptosis in T-ALL MOLT-4 cells. • Plumbagin activates phosphorylation of stress-activated protein kinase (SAPK) JNK and p38. • Plumbagin inhibits LPS-mediated NF-κB signaling cascade. • Plumbagin inhibits LPS-mediated transcriptional activity of pro-inflammatory cytokines.

  17. CD8+CD122+CD49dlow regulatory T cells maintain T-cell homeostasis by killing activated T cells via Fas/FasL-mediated cytotoxicity.

    Science.gov (United States)

    Akane, Kazuyuki; Kojima, Seiji; Mak, Tak W; Shiku, Hiroshi; Suzuki, Haruhiko

    2016-03-01

    The Fas/FasL (CD95/CD178) system is required for immune regulation; however, it is unclear in which cells, when, and where Fas/FasL molecules act in the immune system. We found that CD8(+)CD122(+) cells, which are mostly composed of memory T cells in comparison with naïve cells in the CD8(+)CD122(-) population, were previously shown to include cells with regulatory activity and could be separated into CD49d(low) cells and CD49d(high) cells. We established in vitro and in vivo experimental systems to evaluate the regulatory activity of CD122(+) cells. Regulatory activity was observed in CD8(+)CD122(+)CD49d(low) but not in CD8(+)CD122(+)CD49d(high) cells, indicating that the regulatory cells in the CD8(+)CD122(+) population could be narrowed down to CD49d(low) cells. CD8(+)CD122(-) cells taken from lymphoproliferation (lpr) mice were resistant to regulation by normal CD122(+) Tregs. CD122(+) Tregs taken from generalized lymphoproliferative disease (gld) mice did not regulate wild-type CD8(+)CD122(-) cells, indicating that the regulation by CD122(+) Tregs is Fas/FasL-dependent. CD122(+) Tregs taken from IL-10-deficient mice could regulate CD8(+)CD122(-) cells as equally as wild-type CD122(+) Tregs both in vitro and in vivo. MHC class I-missing T cells were not regulated by CD122(+) Tregs in vitro. CD122(+) Tregs also regulated CD4(+) cells in a Fas/FasL-dependent manner in vitro. These results suggest an essential role of Fas/FasL as a terminal effector of the CD122(+) Tregs that kill activated T cells to maintain immune homeostasis.

  18. Mast cell function modulating IgE-mediated allergy

    Directory of Open Access Journals (Sweden)

    Ruby Pawankar

    1999-01-01

    Full Text Available Allergic diseases, such as atopic rhinitis, bronchial asthma and urticaria, are prevalent and increasing in frequency. Mast cells are known to play a central role in the immediate phase reaction of allergic diseases through the IgE-mediated release of a variety of chemical mediators, such as histamine, leukotrienes and prostaglandins. In contrast, T lymphocytes, basophils and eosinophils are thought to be responsible for inducing the late phase response. However, whether the mast cell can be simplistically assigned a role in the immediate phase allergic response and whether mast cells are necessary for the ongoing allergic response, including the development of hyperresponsiveness, remains to be completely studied. In the present article, the author will discuss the integrated roles of mast cells in IgE-mediated allergic inflammation, with specific emphasis on the roles of mast cell-derived cytokines in the late phase allergic response and chronic allergic inflammation.

  19. The CD8+ T Cell-Mediated Immunity Induced by HPV-E6 Uploaded in Engineered Exosomes Is Improved by ISCOMATRIXTM Adjuvant

    Science.gov (United States)

    Manfredi, Francesco; di Bonito, Paola; Ridolfi, Barbara; Anticoli, Simona; Arenaccio, Claudia; Chiozzini, Chiara; Baz Morelli, Adriana; Federico, Maurizio

    2016-01-01

    We recently described the induction of an efficient CD8+ T cell-mediated immune response against a tumor-associated antigen (TAA) uploaded in engineered exosomes used as an immunogen delivery tool. This immune response cleared tumor cells inoculated after immunization, and controlled the growth of tumors implanted before immunization. We looked for new protocols aimed at increasing the CD8+ T cell specific response to the antigen uploaded in engineered exosomes, assuming that an optimized CD8+ T cell immune response would correlate with a more effective depletion of tumor cells in the therapeutic setting. By considering HPV-E6 as a model of TAA, we found that the in vitro co-administration of engineered exosomes and ISCOMATRIXTM adjuvant, i.e., an adjuvant composed of purified ISCOPREPTM saponin, cholesterol, and phospholipids, led to a stronger antigen cross-presentation in both B- lymphoblastoid cell lines ( and monocyte-derived immature dendritic cells compared with that induced by the exosomes alone. Consistently, the co-inoculation in mice of ISCOMATRIXTM adjuvant and engineered exosomes induced a significant increase of TAA-specific CD8+ T cells compared to mice immunized with the exosomes alone. This result holds promise for effective usage of exosomes as well as alternative nanovesicles in anti-tumor therapeutic approaches. PMID:27834857

  20. Designing bovine T cell vaccines via reverse immunology

    DEFF Research Database (Denmark)

    Nene, Vishvanath; Svitek, Nicholas; Toye, Philip

    2012-01-01

    T cell responses contribute to immunity against many intracellular infections. There is, for example, strong evidence that major histocompatibility complex (MHC) class I-restricted cytotoxic T lymphocytes (CTLs) play an essential role in mediating immunity to East Coast fever (ECF), a fatal lymph...

  1. Blockade of CD7 expression in T cells for effective chimeric antigen receptor targeting of T-cell malignancies.

    Science.gov (United States)

    Png, Yi Tian; Vinanica, Natasha; Kamiya, Takahiro; Shimasaki, Noriko; Coustan-Smith, Elaine; Campana, Dario

    2017-11-28

    Effective immunotherapies for T-cell malignancies are lacking. We devised a novel approach based on chimeric antigen receptor (CAR)-redirected T lymphocytes. We selected CD7 as a target because of its consistent expression in T-cell acute lymphoblastic leukemia (T-ALL), including the most aggressive subtype, early T-cell precursor (ETP)-ALL. In 49 diagnostic T-ALL samples (including 14 ETP-ALL samples), median CD7 expression was >99%; CD7 expression remained high at relapse (n = 14), and during chemotherapy (n = 54). We targeted CD7 with a second-generation CAR (anti-CD7-41BB-CD3ζ), but CAR expression in T lymphocytes caused fratricide due to the presence of CD7 in the T cells themselves. To downregulate CD7 and control fratricide, we applied a new method (protein expression blocker [PEBL]), based on an anti-CD7 single-chain variable fragment coupled with an intracellular retention domain. Transduction of anti-CD7 PEBL resulted in virtually instantaneous abrogation of surface CD7 expression in all transduced T cells; 2.0% ± 1.7% were CD7 + vs 98.1% ± 1.5% of mock-transduced T cells (n = 5; P < .0001). PEBL expression did not impair T-cell proliferation, interferon-γ and tumor necrosis factor-α secretion, or cytotoxicity, and eliminated CAR-mediated fratricide. PEBL-CAR T cells were highly cytotoxic against CD7 + leukemic cells in vitro and were consistently more potent than CD7 + T cells spared by fratricide. They also showed strong anti-leukemic activity in cell line- and patient-derived T-ALL xenografts. The strategy described in this study fits well with existing clinical-grade cell manufacturing processes and can be rapidly implemented for the treatment of patients with high-risk T-cell malignancies.

  2. Colorectal cancer cells suppress CD4+ T cells immunity through canonical Wnt signaling.

    Science.gov (United States)

    Sun, Xuan; Liu, Suoning; Wang, Daguang; Zhang, Yang; Li, Wei; Guo, Yuchen; Zhang, Hua; Suo, Jian

    2017-02-28

    Understanding how colorectal cancer escapes from immunosurveillance and immune attack is important for developing novel immunotherapies for colorectal cancer. In this study we evaluated the role of canonical Wnt signaling in the regulation of T cell function in a mouse colorectal cancer model. We found that colorectal cancer cells expressed abundant Wnt ligands, and intratumoral T cells expressed various Frizzled proteins. Meanwhile, both active β-catenin and total β-catenin were elevated in intratumoral T cells. In vitro study indicated that colorectal cancer cells suppressed IFN-γ expression and increased IL-17a expression in activated CD4+ T cells. However, the cytotoxic activity of CD8+ T cells was not altered by colorectal cancer cells. To further evaluate the importance of Wnt signaling for CD4+ T cell-mediated cancer immunity, β-catenin expression was enforced in CD4+ T cells using lentiviral transduction. In an adoptive transfer model, enforced expression of β-catenin in intratumoral CD4+ T cells increased IL-17a expression, enhanced proliferation and inhibited apoptosis of colorectal cancer cells. Taken together, our study disclosed a new mechanism by which colorectal cancer impairs T cell immunity.

  3. MMP19 is essential for T cell development and T cell-mediated cutaneous immune responses

    Czech Academy of Sciences Publication Activity Database

    Beck, Inken; Ruckert, R.; Brandt, K.; Mueller, M.S.; Sadowski, T.; Brauer, R.; Schirmacher, P.; Mentlein, R.; Sedláček, Radislav

    2008-01-01

    Roč. 3, č. 6 (2008), e2343-e2343 E-ISSN 1932-6203 Institutional research plan: CEZ:AV0Z50520514; CEZ:AV0Z50520701 Keywords : matrix metalloproteinase * T cell * immune response Subject RIV: EB - Genetics ; Molecular Biology

  4. Immunoregulatory T cells in man. Histamine-induced suppressor T cells are derived from a Leu 2+ (T8+) subpopulation distinct from that which gives rise to cytotoxic T cells

    International Nuclear Information System (INIS)

    Sansoni, P.; Silverman, E.D.; Khan, M.M.; Melmon, K.L.; Engleman, E.G.

    1985-01-01

    One mechanism of histamine-mediated inhibition of the immune response in man is to activate T suppressor cells that bear the Leu 2 (OKT8) marker. The current study was undertaken to characterize the histamine-induced suppressor cell using a monoclonal antibody (9.3) shown previously to distinguish cytotoxic T cells from antigen-specific suppressor T cells. Leu 2+ cells isolated from peripheral blood were further separated with antibody 9.3 into Leu 2+, 9.3+, and Leu 2+, 9.3- subsets and each subset was incubated with different concentrations of histamine before determining their ability to suppress immune responses in vitro. The results indicate that the Leu 2+, 9.3- subpopulation includes all histamine-induced suppressor cells, that 10(-4) M histamine is the optimal concentration for suppressor cell induction, and that exposure of Leu 2+, 9.3- cells to histamine for 30 s is sufficient to initiate the induction process. After treatment with histamine these cells inhibit both phytohemagglutinin-induced T cell proliferation and pokeweed mitogen-induced B cell differentiation. The suppression of phytohemagglutinin-induced proliferation was resistant to x-irradiation with 1,200 rad, either before or after histamine exposure, suggesting that Leu 2+, 9.3- cells need not proliferate to become suppressor cells or exert suppression. Moreover, suppression by these cells was not due to altered kinetics of the response. Finally, a histamine type 2 receptor antagonist (cimetidine) but not a type 1 receptor antagonist (mepyramine) blocked the induction of suppressor cells. On the basis of these results and our previous studies of antigen specific suppressor cells, we conclude that Leu 2+ suppressor cells in man are derived from a precursor pool that is phenotypically distinct from cells that can differentiate into cytotoxic T cells

  5. IL-12-mediated STAT4 signaling and TCR signal strength cooperate in the induction of CD40L in human and mouse CD8+ T cells.

    Science.gov (United States)

    Stark, Regina; Hartung, Anett; Zehn, Dietmar; Frentsch, Marco; Thiel, Andreas

    2013-06-01

    CD40L is one of the key molecules bridging the activation of specific T cells and the maturation of professional and nonprofessional antigen-presenting cells including B cells. CD4(+) T cells have been regarded as the major T-cell subset that expresses CD40L upon cognate activation; however, we demonstrate here that a putative CD8(+) helper T-cell subset expressing CD40L is induced in human and murine CD8(+) T cells in vitro and in mice immunized with antigen-pulsed dendritic cells. IL-12 and STAT4-mediated signaling was the major instructive cytokine signal boosting the ability of CD8(+) T cells to express CD40L both in vitro and in vivo. Additionally, TCR signaling strength modulated CD40L expression in CD8(+) T cells after primary differentiation in vitro as well as in vivo. The induction of CD40L in CD8(+) T cells regulated by IL-12 and TCR signaling may enable CD8(+) T cells to respond autonomously of CD4(+) T cells. Thus, we propose that under proinflammatory conditions, a self-sustaining positive feedback loop could facilitate the efficient priming of T cells stimulated by high affinity peptide displaying APCs. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. An inducible transgenic mouse model for immune mediated hepatitis showing clearance of antigen expressing hepatocytes by CD8+ T cells.

    Directory of Open Access Journals (Sweden)

    Marcin Cebula

    Full Text Available The liver has the ability to prime immune responses against neo antigens provided upon infections. However, T cell immunity in liver is uniquely modulated by the complex tolerogenic property of this organ that has to also cope with foreign agents such as endotoxins or food antigens. In this respect, the nature of intrahepatic T cell responses remains to be fully characterized. To gain deeper insight into the mechanisms that regulate the CD8+ T cell responses in the liver, we established a novel OVA_X_CreER(T2 mouse model. Upon tamoxifen administration OVA antigen expression is observed in a fraction of hepatocytes, resulting in a mosaic expression pattern. To elucidate the cross-talk of CD8+ T cells with antigen-expressing hepatocytes, we adoptively transferred K(b/OVA257-264-specific OT-I T cells to OVA_X_CreER(T2 mice or generated triple transgenic OVA_X CreER(T2_X_OT-I mice. OT-I T cells become activated in OVA_X_CreER(T2 mice and induce an acute and transient hepatitis accompanied by liver damage. In OVA_X_CreER(T2_X_OT-I mice, OVA induction triggers an OT-I T cell mediated, fulminant hepatitis resulting in 50% mortality. Surviving mice manifest a long lasting hepatitis, and recover after 9 weeks. In these experimental settings, recovery from hepatitis correlates with a complete loss of OVA expression indicating efficient clearance of the antigen-expressing hepatocytes. Moreover, a relapse of hepatitis can be induced upon re-induction of cured OVA_X_CreER(T2_X_OT-I mice indicating absence of tolerogenic mechanisms. This pathogen-free, conditional mouse model has the advantage of tamoxifen inducible tissue specific antigen expression that reflects the heterogeneity of viral antigen expression and enables the study of intrahepatic immune responses to both de novo and persistent antigen. It allows following the course of intrahepatic immune responses: initiation, the acute phase and antigen clearance.

  7. Dasatinib-Induced T-Cell-Mediated Colitis: A Case Report and Review of the Literature.

    Science.gov (United States)

    Shanshal, Mohamed; Shakespeare, Andrew; Thirumala, Seshadri; Fenton, Boyd; Quick, Donald P

    2016-01-01

    Dasatinib is a potent inhibitor of the altered tyrosine kinase activity in disease states associated with BCR/ABL1. This agent has been shown to exhibit broad off-target kinase inhibition and immunomodulating properties. These effects may be responsible for dasatinib's unique side effects including a distinctive form of hemorrhagic colitis. We report a case of hemorrhagic colitis associated with dasatinib use in a patient with chronic myelogenous leukemia. Colon biopsies at the time of symptomatic colitis confirmed CD3+CD8+ T cell infiltration. The process rapidly resolved following drug discontinuation, but relapsed when rechallenged with a reduced dose of dasatinib. Colitis did not recur when the patient was treated with an alternative agent. A literature review of prior cases involving dasatinib-induced T-cell mediated colitis provides insight into commonalities that may facilitate the recognition and management of this entity. Most incidences occurred after a 3-month drug exposure and may be accompanied by large granular lymphocytes. The process uniformly resolves within a few days following drug discontinuation and will generally recur in a shorter period of time if the drug is reintroduced. Most patients will require an alternative agent, although select patients could be continued on dasatinib if other options are limited. © 2016 S. Karger AG, Basel.

  8. On the use of an appropriate TdT-mediated dUTP-biotin nick end labeling assay to identify apoptotic cells.

    OpenAIRE

    Lebon, C.; Rodriguez, G.V.; Zaoui, I.E.; Jaadane, I.; Behar-Cohen, F.; Torriglia, A.

    2015-01-01

    Apoptosis is an essential cellular mechanism involved in many processes such as embryogenesis, metamorphosis, and tissue homeostasis. DNA fragmentation is one of the key markers of this form of cell death. DNA fragmentation is executed by endogenous endonucleases such as caspase-activated DNase (CAD) in caspase-dependent apoptosis. The TUNEL (TdT-mediated dUTP-biotin nick end labeling) technique is the most widely used method to identify apoptotic cells in a tissue or culture and to assess dr...

  9. The interaction of dendritic cells and γδ T cells promotes the activation of γδ T cells in experimental autoimmune uveitis

    Directory of Open Access Journals (Sweden)

    Beibei Wang

    2017-03-01

    Full Text Available Uveitis is a severe inflammatory disease that can cause visual impairment. Recently, activated γδ T cells were proved to play a central role in the development of experimental autoimmune uveitis (EAU. However, the mechanism underlying γδ T-cell activation in EAU is incompletely known. In this study, we determined the percentage changes in and the phenotypes of γδ T cells and dendritic cells (DCs obtained from the spleens of immunized C57BL/6 (B6 mice, an animal model of EAU. We found that the number of γδ T cells and DCs obviously increased during the inflammation phase of EAU (days 16–20 of our experiment, and that during this time, γδ T cells expressed high levels of CD69 and the integrin lymphocyte function–associated antigen-1 (LFA-1 and secreted high levels of interleukin (IL-17A. Moreover, DCs obtained during this phase expressed high levels of CD80, CD83, CD86, and intracellular cell adhesion molecule-1 (ICAM-1. Furthermore, we studied the interaction between DCs and γδ T cells by using flow cytometry and confocal microscopy in order to determine whether DCs affected γδ T-cell activation in vitro. Co-cultures of the two types of cells showed that DCs induced high levels of CD69, LFA-1, and IL-17A in γδ T cells. Imaging studies revealed contact between the DCs and γδ T cells. This interaction was mediated by the accumulation of ICAM-1 and LFA-1 at the interface of DCs-γδ T cells. Thus, the activation of γδ T cells in EAU was promoted by DCs interacting with γδ T cells.

  10. The essential role of G protein-coupled receptor (GPCR) signaling in regulating T cell immunity.

    Science.gov (United States)

    Wang, Dashan

    2018-06-01

    The aim of this paper is to clarify the critical role of GPCR signaling in T cell immunity. The G protein-coupled receptors (GPCRs) are the most common targets in current pharmaceutical industry, and represent the largest and most versatile family of cell surface communicating molecules. GPCRs can be activated by a diverse array of ligands including neurotransmitters, chemokines as well as sensory stimuli. Therefore, GPCRs are involved in many key cellular and physiological processes, such as sense of light, taste and smell, neurotransmission, metabolism, endocrine and exocrine secretion. In recent years, GPCRs have been found to play an important role in immune system. T cell is an important type of immune cell, which plays a central role in cell-mediated immunity. A variety of GPCRs and their signaling mediators (RGS proteins, GRKs and β-arrestin) have been found to express in T cells and involved T cell-mediated immunity. We will summarize the role of GPCR signaling and their regulatory molecules in T cell activation, homeostasis and function in this article. GPCR signaling plays an important role in T cell activation, homeostasis and function. GPCR signaling is critical in regulating T cell immunity.

  11. Nuclear Phosphoproteomic Screen Uncovers ACLY as Mediator of IL-2-induced Proliferation of CD4+ T lymphocytes

    DEFF Research Database (Denmark)

    Osinalde, Nerea; Mitxelena, Jone; Sánchez-Quiles, Virginia

    2016-01-01

    -mediated T-cell responses. ACLY becomes phosphorylated on serine 455 in T lymphocytes upon IL-2-driven activation of AKT, and depletion or inactivation of ACLY compromises IL-2-promoted T-cell growth. Mechanistically, we demonstrate that ACLY is required for enhancing histone acetylation levels...

  12. c-Myb Regulates the T-Bet-Dependent Differentiation Program in B Cells to Coordinate Antibody Responses

    Directory of Open Access Journals (Sweden)

    Dana Piovesan

    2017-04-01

    Full Text Available Summary: Humoral immune responses are tailored to the invading pathogen through regulation of key transcription factors and their networks. This is critical to establishing effective antibody-mediated responses, yet it is unknown how B cells integrate pathogen-induced signals to drive or suppress transcriptional programs specialized for each class of pathogen. Here, we detail the key role of the transcription factor c-Myb in regulating the T-bet-mediated anti-viral program. Deletion of c-Myb in mature B cells significantly increased serum IgG2c and CXCR3 expression by upregulating T-bet, normally suppressed during Th2-cell-mediated responses. Enhanced expression of T-bet resulted in aberrant plasma cell differentiation within the germinal center, mediated by CXCR3 expression. These findings identify a dual role for c-Myb in limiting inappropriate effector responses while coordinating plasma cell differentiation with germinal center egress. Identifying such intrinsic regulators of specialized antibody responses can assist in vaccine design and therapeutic intervention in B-cell-mediated immune disorders. : Piovesan et al. examine how B cells establish transcriptional programs that result in tailored responses to invading pathogens. The authors find that the transcription factor c-Myb represses the T-bet-mediated anti-viral program in B cells. c-Myb limits inappropriate effector responses while coordinating plasma cell differentiation with germinal center egress. Keywords: B cells, c-Myb, T-bet, immunoglobulin, CXCR3, plasma cell, germinal center

  13. Freeze-thaw lysates of Plasmodium falciparum-infected red blood cells induce differentiation of functionally competent regulatory T cells from memory T cells.

    Science.gov (United States)

    Finney, Olivia C; Lawrence, Emma; Gray, Alice P; Njie, Madi; Riley, Eleanor M; Walther, Michael

    2012-07-01

    In addition to naturally occurring regulatory T (nTreg) cells derived from the thymus, functionally competent Treg cells can be induced in vitro from peripheral blood lymphocytes in response to TCR stimulation with cytokine costimulation. Using these artificial stimulation conditions, both naïve as well as memory CD4(+) T cells can be converted into induced Treg (iTreg) cells, but the cellular origin of such iTreg cells in vivo or in response to more physiologic stimulation with pathogen-derived antigens is less clear. Here, we demonstrate that a freeze/thaw lysate of Plasmodium falciparum schizont extract (PfSE) can induce functionally competent Treg cells from peripheral lymphocytes in a time- and dose-dependent manner without the addition of exogenous costimulatory factors. The PfSE-mediated induction of Treg cells required the presence of nTreg cells in the starting culture. Further experiments mixing either memory or naïve T cells with antigen presenting cells and CFSE-labeled Treg cells identified CD4(+) CD45RO(+) CD25(-) memory T cells rather than Treg cells as the primary source of PfSE-induced Treg cells. Taken together, these data suggest that in the presence of nTreg cells, PfSE induces memory T cells to convert into iTreg cells that subsequently expand alongside PfSE-induced effector T cells. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Decreased Expression of T-Cell Costimulatory Molecule CD28 on CD4 and CD8 T Cells of Mexican Patients with Pulmonary Tuberculosis

    Directory of Open Access Journals (Sweden)

    German Bernal-Fernandez

    2010-01-01

    Full Text Available Patients with tuberculosis frequently develop anergy, a state of T-cell hyporesponsiveness in which defective T-cell costimulation could be a factor. To know if the expression of T-cell costimulatory molecules was altered in tuberculosis, we analyzed the peripheral blood T-cell phenotype of 23 Mexican patients with pulmonary tuberculosis. There was severe CD4 (P<.001 and CD8 (P<.01 lymphopenia and upregulation of costimulatory molecule CD30 on CD4 and CD8 T cells (P<.05; this increase was higher in relapsing tuberculosis. The main finding was severe downregulation of the major costimulatory molecule CD28 on both CD8 and CD4 T cells (P<.001. Depletion of the CD4/CD28 subset, a hitherto undescribed finding, is relevant because CD4 T cells constitute the main arm of the cell-mediated antimycobacterial immune response.

  15. R5-SHIV induces multiple defects in T cell function during early infection of rhesus macaques including accumulation of T reg cells in lymph nodes.

    Directory of Open Access Journals (Sweden)

    Michael Santosuosso

    2011-04-01

    Full Text Available HIV-1 is a pathogen that T cell responses fail to control. HIV-1gp120 is the surface viral envelope glycoprotein that interacts with CD4 T cells and mediates entry. HIV-1gp120 has been implicated in immune dysregulatory functions that may limit anti-HIV antigen-specific T cell responses. We hypothesized that in the context of early SHIV infection, immune dysregulation of antigen-specific T-effector cell and regulatory functions would be detectable and that these would be associated or correlated with measurable concentrations of HIV-1gp120 in lymphoid tissues.Rhesus macaques were intravaginally inoculated with a Clade C CCR5-tropic simian-human immunodeficiency virus, SHIV-1157ipd3N4. HIV-1gp120 levels, antigen-specificity, levels of apoptosis/anergy and frequency and function of Tregs were examined in lymph node and blood derived T cells at 5 and 12 weeks post inoculation.We observed reduced responses to Gag in CD4 and gp120 in CD8 lymph node-derived T cells compared to the peripheral blood at 5 weeks post-inoculation. Reduced antigen-specific responses were associated with higher levels of PD-1 on lymph node-derived CD4 T cells as compared to peripheral blood and uninfected lymph node-derived CD4 T cells. Lymph nodes contained increased numbers of Tregs as compared to peripheral blood, which positively correlated with gp120 levels; T regulatory cell depletion restored CD8 T cell responses to Gag but not to gp120. HIV gp120 was also able to induce T regulatory cell chemotaxis in a dose-dependent, CCR5-mediated manner. These studies contribute to our broader understanding of the ways in which HIV-1 dysregulates T cell function and localization during early infection.

  16. TGF-beta and 'adaptive' Foxp3(+) regulatory T cells.

    Science.gov (United States)

    Chen, Wanjun; Konkel, Joanne E

    2010-02-01

    In naïve T cells transforming growth factor-beta (TGF-beta) induces Foxp3, a transcription factor essential for programming and developing T regulatory cells (Treg cells). This finding reveals a physiological factor which can turn on the Foxp3 gene and establishes an experimental approach to induce antigen-specific Treg cells as a potential therapy for human diseases. While this role for TGF-beta is well confirmed, several critical questions remain largely unanswered and await further investigation. In this regard, it is imperative to understand the molecular pathways by which TGF-beta signaling initiates and regulates Foxp3 expression. It is also important to elucidate which factors and/or cytokines influence the TGF-beta-mediated conversion of naïve T cells and how to create an immunologically regulatory milieu to facilitate Treg cell generation in vivo. In this short article, we will highlight the key findings and recent progress in the field, discuss the molecular mechanisms underlying the TGF-beta-mediated induction of Foxp3, and attempt to outline the challenges ahead.

  17. Infection of CD4+ T lymphocytes by the human T cell leukemia virus type 1 is mediated by the glucose transporter GLUT-1: Evidence using antibodies specific to the receptor's large extracellular domain

    International Nuclear Information System (INIS)

    Jin, Qingwen; Agrawal, Lokesh; VanHorn-Ali, Zainab; Alkhatib, Ghalib

    2006-01-01

    To analyze HTLV-1 cytotropism, we developed a highly sensitive vaccinia virus-based assay measuring activation of a reporter gene upon fusion of two distinct cell populations. We used this system in a functional cDNA screening to isolate and confirm that the glucose transporter protein 1 (GLUT-1) is a receptor for HTLV-1. GLUT-1 is a ubiquitously expressed plasma membrane glycoprotein with 12 transmembrane domains and 6 extracellular loops (ECL). We demonstrate for the first time that peptide antibodies (GLUT-IgY) raised in chicken to the large extracellular loop (ECL1) detect GLUT-1 at the cell surface and inhibit envelope (Env)-mediated fusion and infection. Efficient GLUT-IgY staining was detected with peripheral blood CD4 + lymphocytes purified by positive selection. Further, GLUT-IgY caused efficient inhibition of Env-mediated fusion and infection of CD4 + T and significantly lower inhibition of CD8 + T lymphocytes. The specificity of GLUT-IgY antibodies to GLUT-1 was demonstrated by ECL1 peptide competition studies. Grafting ECL1 of GLUT-1 onto the receptor-negative GLUT-3 conferred significant receptor activity. In contrast, grafting ECL1 of GLUT-3 onto GLUT-1 resulted in a significant loss of the receptor activity. The ECL1-mediated receptor activity was efficiently blocked with four different human monoclonal antibody (HMab) to HTLV-1 Env. The ECL1-derived peptide blocked HTLV-1 Env-mediated fusion with several nonhuman mammalian cell lines. The results demonstrate the utilization of cell surface GLUT-1 in HTLV-1 infection of CD4 + T lymphocytes and implicate a critical role for the ECL1 region in viral tropism

  18. Recruitment of Mediator Complex by Cell Type and Stage-Specific Factors Required for Tissue-Specific TAF Dependent Gene Activation in an Adult Stem Cell Lineage.

    Science.gov (United States)

    Lu, Chenggang; Fuller, Margaret T

    2015-12-01

    Onset of terminal differentiation in adult stem cell lineages is commonly marked by robust activation of new transcriptional programs required to make the appropriate differentiated cell type(s). In the Drosophila male germ line stem cell lineage, the switch from proliferating spermatogonia to spermatocyte is accompanied by one of the most dramatic transcriptional changes in the fly, as over 1000 new transcripts turn on in preparation for meiosis and spermatid differentiation. Here we show that function of the coactivator complex Mediator is required for activation of hundreds of new transcripts in the spermatocyte program. Mediator appears to act in a sequential hierarchy, with the testis activating Complex (tMAC), a cell type specific form of the Mip/dREAM general repressor, required to recruit Mediator subunits to the chromatin, and Mediator function required to recruit the testis TAFs (tTAFs), spermatocyte specific homologs of subunits of TFIID. Mediator, tMAC and the tTAFs co-regulate expression of a major set of spermatid differentiation genes. The Mediator subunit Med22 binds the tMAC component Topi when the two are coexpressed in S2 cells, suggesting direct recruitment. Loss of Med22 function in spermatocytes causes meiosis I maturation arrest male infertility, similar to loss of function of the tMAC subunits or the tTAFs. Our results illuminate how cell type specific versions of the Mip/dREAM complex and the general transcription machinery cooperate to drive selective gene activation during differentiation in stem cell lineages.

  19. The role of gamma delta T cells in haematopoietic stem cell transplantation

    DEFF Research Database (Denmark)

    Minculescu, L; Sengeløv, H

    2015-01-01

    transplantation modalities increasingly focuses on selective cell depletion and graft engineering with the aim of retaining beneficial immune donor cells for the graft-versus-leukaemia (GVL) effect. In this context, the adoptive and especially innate effector functions of γδ T cells together with clinical studies...... recognition independent from the major histocompatibility complex (MHC) allows for the theoretical possibility of mediating GVL without an allogeneic response in terms of GVHD. Early studies on the impact of γδ T cells in HSCT have reported conflicting results. Recent studies, however, do suggest an overall...

  20. Designing bovine T-cell vaccines via reverse immunology

    Science.gov (United States)

    T-cell responses contribute to immunity against many intra-cellular infections. There is, for example, strong evidence that major histocompatibility complex (MHC) class I restricted cytotoxic T lymphocytes (CTLs) play an essential role in mediating immunity to East Coast fever (ECF), a fatal lymphop...

  1. Regulation of CD8+ T cell responses to retinal antigen by local FoxP3+ regulatory T cells

    Directory of Open Access Journals (Sweden)

    Scott W McPherson

    2012-06-01

    Full Text Available While pathogenic CD4 T cells are well known mediators of autoimmune uveoretinitis, CD8 T cells can also be uveitogenic. Since preliminary studies indicated that C57BL/6 mice were minimally susceptible to autoimmune uveoretinitis induction by CD8 T cells, the basis of the retinal disease resistance was sought. Mice that express β-galactosidase (βgal on a retina-specific promoter (arrβgal mice were backcrossed to mice expressing green fluorescent protein and diphtheria toxin receptor under control of the Foxp3 promoter (Foxp3-DTR/GFP mice, and to T cell receptor transgenic mice that produce βgal specific CD8 T cells (BG1 mice. These mice were used to explore the role of regulatory T cells in the resistance to retinal autoimmune disease. Experiments with T cells from double transgenic BG1 x Foxp3-DTR/GFP mice transferred into Foxp3-DTR/GFP x arrβgal mice confirmed that the retina was well protected from attempts to induce disease by adoptive transfer of activated BG1 T cells. The successful induction of retinal disease following unilateral intraocular administration of diphtheria toxin to deplete regulatory T cells showed that the protective activity was dependent on local, toxin-sensitive regulatory T cells; the opposite, untreated eye remained disease-free. Although there were very few Foxp3+ regulatory T cells in the parenchyma of quiescent retina, and they did not accumulate in retina, their depletion by local toxin administration led to disease susceptibility. We propose that these regulatory T cells modulate the pathogenic activity of βgal-specific CD8 T cells in the retinas of arrβgal mice on a local basis, allowing immunoregulation to be responsive to local conditions.

  2. Genetic engineering with T cell receptors.

    Science.gov (United States)

    Zhang, Ling; Morgan, Richard A

    2012-06-01

    In the past two decades, human gene transfer research has been translated from a laboratory technology to clinical evaluation. The success of adoptive transfer of tumor-reactive lymphocytes to treat the patients with metastatic melanoma has led to new strategies to redirect normal T cells to recognize tumor antigens by genetic engineering with tumor antigen-specific T cell receptor (TCR) genes. This new strategy can generate large numbers of defined antigen-specific cells for therapeutic application. Much progress has been made to TCR gene transfer systems by optimizing gene expression and gene transfer protocols. Vector and protein modifications have enabled excellent expression of introduced TCR chains in human lymphocytes with reduced mis-pairing between the introduced and endogenous TCR chains. Initial clinical studies have demonstrated that TCR gene-engineered T cells could mediate tumor regression in vivo. In this review, we discuss the progress and prospects of TCR gene-engineered T cells as a therapeutic strategy for treating patients with melanoma and other cancers. Published by Elsevier B.V.

  3. T Cell Receptor Vβ Staining Identifies the Malignant Clone in Adult T cell Leukemia and Reveals Killing of Leukemia Cells by Autologous CD8+ T cells.

    Directory of Open Access Journals (Sweden)

    Aileen G Rowan

    2016-11-01

    Full Text Available There is growing evidence that CD8+ cytotoxic T lymphocyte (CTL responses can contribute to long-term remission of many malignancies. The etiological agent of adult T-cell leukemia/lymphoma (ATL, human T lymphotropic virus type-1 (HTLV-1, contains highly immunogenic CTL epitopes, but ATL patients typically have low frequencies of cytokine-producing HTLV-1-specific CD8+ cells in the circulation. It remains unclear whether patients with ATL possess CTLs that can kill the malignant HTLV-1 infected clone. Here we used flow cytometric staining of TCRVβ and cell adhesion molecule-1 (CADM1 to identify monoclonal populations of HTLV-1-infected T cells in the peripheral blood of patients with ATL. Thus, we quantified the rate of CD8+-mediated killing of the putative malignant clone in ex vivo blood samples. We observed that CD8+ cells from ATL patients were unable to lyse autologous ATL clones when tested directly ex vivo. However, short in vitro culture restored the ability of CD8+ cells to kill ex vivo ATL clones in some donors. The capacity of CD8+ cells to lyse HTLV-1 infected cells which expressed the viral sense strand gene products was significantly enhanced after in vitro culture, and donors with an ATL clone that expressed the HTLV-1 Tax gene were most likely to make a detectable lytic CD8+ response to the ATL cells. We conclude that some patients with ATL possess functional tumour-specific CTLs which could be exploited to contribute to control of the disease.

  4. The 3 major types of innate and adaptive cell-mediated effector immunity.

    Science.gov (United States)

    Annunziato, Francesco; Romagnani, Chiara; Romagnani, Sergio

    2015-03-01

    The immune system has tailored its effector functions to optimally respond to distinct species of microbes. Based on emerging knowledge on the different effector T-cell and innate lymphoid cell (ILC) lineages, it is clear that the innate and adaptive immune systems converge into 3 major kinds of cell-mediated effector immunity, which we propose to categorize as type 1, type 2, and type 3. Type 1 immunity consists of T-bet(+) IFN-γ-producing group 1 ILCs (ILC1 and natural killer cells), CD8(+) cytotoxic T cells (TC1), and CD4(+) TH1 cells, which protect against intracellular microbes through activation of mononuclear phagocytes. Type 2 immunity consists of GATA-3(+) ILC2s, TC2 cells, and TH2 cells producing IL-4, IL-5, and IL-13, which induce mast cell, basophil, and eosinophil activation, as well as IgE antibody production, thus protecting against helminthes and venoms. Type 3 immunity is mediated by retinoic acid-related orphan receptor γt(+) ILC3s, TC17 cells, and TH17 cells producing IL-17, IL-22, or both, which activate mononuclear phagocytes but also recruit neutrophils and induce epithelial antimicrobial responses, thus protecting against extracellular bacteria and fungi. On the other hand, type 1 and 3 immunity mediate autoimmune diseases, whereas type 2 responses can cause allergic diseases. Copyright © 2014 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  5. Human CD4+ T cells lyse target cells via granzyme/perforin upon circumvention of MHC class II restriction by an antibody-like immunoreceptor.

    Science.gov (United States)

    Hombach, Andreas; Köhler, Heike; Rappl, Gunter; Abken, Hinrich

    2006-10-15

    Immune elimination of tumor cells requires the close cooperation between CD8+ CTL and CD4+ Th cells. We circumvent MHC class II-restriction of CD4+ T cells by expression of a recombinant immunoreceptor with an Ab-derived binding domain redirecting specificity. Human CD4+ T cells grafted with an immunoreceptor specific for carcinoembryonic Ag (CEA) are activated to proliferate and secrete cytokines upon binding to CEA+ target cells. Notably, redirected CD4+ T cells mediate cytolysis of CEA+ tumor cells with high efficiencies. Lysis by redirected CD4+ T cells is independent of death receptor signaling via TNF-alpha or Fas, but mediated by perforin and granzyme because cytolysis is inhibited by blocking the release of cytotoxic granules, but not by blocking of Fas ligand or TNF-alpha. CD4+ T cells redirected by Ab-derived immunoreceptors in a MHC class II-independent fashion substantially extend the power of an adoptive, Ag-triggered immunotherapy not only by CD4+ T cell help, but also by cytolytic effector functions. Because cytolysis is predominantly mediated via granzyme/perforin, target cells that are resistant to death receptor signaling become sensitive to a cytolytic attack by engineered CD4+ T cells.

  6. Human T-cell lymphotropic virus type III infection in a cohort of homosexual men in New York City

    International Nuclear Information System (INIS)

    Stevens, C.E.; Taylor, P.E.; Zang, E.A.

    1986-01-01

    Using blood samples collected since 1978, the authors investigated the epidemiology of human T-cell lymphotropic virus type III (HTLV-III), the etiologic agent of the acquired immunodeficiency syndrome, in a group of 378 homosexually active men who have resided in New York City since the acquire immunodeficiency syndrome epidemic began. The anti-HTLV-III prevalence was 6.6% in sera from 1978 or 1979, and the subsequent annual incidence of seroconversion among susceptible men ranged between 5.5% and 10.6%. The highest incidences were in recent years, even though these men reported a decrease in their sexual activity during this time. These data demonstrate the continuing risk of HTLV-III infections in the homosexual population studied and emphasize the need for more effective prevention of transmission. The year during which antibody was first present was the only factor identified that was associated with altered cell-mediated immunity in antibody-positive men

  7. Human T-cell lymphotropic virus type III infection in a cohort of homosexual men in New York City

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, C.E.; Taylor, P.E.; Zang, E.A.; Morrison, J.M.; Harley, E.J.; de Cordoba, S.R.; Bacino, C.; Ting, R.C.; Bodner, A.J.; Sarngadharan, M.G.; Gallo, R.C.

    1986-04-25

    Using blood samples collected since 1978, the authors investigated the epidemiology of human T-cell lymphotropic virus type III (HTLV-III), the etiologic agent of the acquired immunodeficiency syndrome, in a group of 378 homosexually active men who have resided in New York City since the acquire immunodeficiency syndrome epidemic began. The anti-HTLV-III prevalence was 6.6% in sera from 1978 or 1979, and the subsequent annual incidence of seroconversion among susceptible men ranged between 5.5% and 10.6%. The highest incidences were in recent years, even though these men reported a decrease in their sexual activity during this time. These data demonstrate the continuing risk of HTLV-III infections in the homosexual population studied and emphasize the need for more effective prevention of transmission. The year during which antibody was first present was the only factor identified that was associated with altered cell-mediated immunity in antibody-positive men.

  8. TNF-α blockade induces IL-10 expression in human CD4+ T cells

    NARCIS (Netherlands)

    Evans, Hayley G.; Roostalu, Urmas; Walter, Gina J.; Gullick, Nicola J.; Frederiksen, Klaus S.; Roberts, Ceri A.; Sumner, Jonathan; Baeten, Dominique L.; Gerwien, Jens G.; Cope, Andrew P.; Geissmann, Frederic; Kirkham, Bruce W.; Taams, Leonie S.

    2014-01-01

    IL-17+ CD4+ T (Th17) cells contribute to the pathogenesis of several human inflammatory diseases. Here we demonstrate that TNF inhibitor (TNFi) drugs induce the anti-inflammatory cytokine IL-10 in CD4+ T cells including IL-17+ CD4+ T cells. TNFi-mediated induction of IL-10 in IL-17+ CD4+ T cells is

  9. Cytokines affecting CD4+T regulatory cells in transplant tolerance. II. Interferon gamma (IFN-γ) promotes survival of alloantigen-specific CD4+T regulatory cells.

    Science.gov (United States)

    Nomura, Masaru; Hodgkinson, Suzanne J; Tran, Giang T; Verma, Nirupama D; Robinson, Catherine; Plain, Karren M; Boyd, Rochelle; Hall, Bruce M

    2017-06-01

    CD4 + T cells that transfer alloantigen-specific transplant tolerance are short lived in culture unless stimulated with specific-donor alloantigen and lymphocyte derived cytokines. Here, we examined if IFN-γ maintained survival of tolerance transferring CD4 + T cells. Alloantigen-specific transplant tolerance was induced in DA rats with heterotopic adult PVG heart allografts by a short course of immunosuppression and these grafts functioned for >100days with no further immunosuppression. In previous studies, we found the CD4 + T cells from tolerant rats that transfer tolerance to an irradiated DA host grafted with a PVG heart, lose their tolerance transferring ability after 3days of culture, either with or without donor alloantigen, and effect rejection of specific-donor grafts. If cultures with specific-donor alloantigen are supplemented by supernatant from ConA activated lymphocytes the tolerance transferring cells survive, suggesting these cells depend on cytokines for their survival. In this study, we found addition of rIFN-γ to MLC with specific-donor alloantigen maintained the capacity of tolerant CD4 + T cells to transfer alloantigen-specific tolerance and their ability to suppress PVG allograft rejection mediated by co-administered naïve CD4 + T cells. IFN-γ suppressed the in vitro proliferation of tolerant CD4 + T cells. Tolerant CD4 + CD25 + T cells did not proliferate in MLC to PVG stimulator cells with no cytokine added, but did when IFN-γ was present. IFN-γ did not alter proliferation of tolerant CD4 + CD25 + T cells to third-party Lewis. Tolerant CD4 + CD25 + T cells' expression of IFN-γ receptor (IFNGR) was maintained in culture when IFN-γ was present. This study suggested that IFN-γ maintained tolerance mediating alloantigen-specific CD4 + CD25 + T cells. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  10. T-cell proliferative responses following sepsis in neonatal rats.

    Science.gov (United States)

    Dallal, Ousama; Ravindranath, Thyyar M; Choudhry, Mashkoor A; Kohn, Annamarie; Muraskas, Jonathan K; Namak, Shahla Y; Alattar, Mohammad H; Sayeed, Mohammed M

    2003-01-01

    Both experimental and clinical evidence suggest a suppression of T-cell function in burn and sepsis. The objective of the present study was to evaluate splenocyte and purified T-cell proliferative response and IL-2 production in septic neonatal rats. We also examined if alterations in T-cell proliferation and IL-2 production in neonatal sepsis is due to elevation in PGE2. PGE2 is known to play a significant role in T-cell suppression during sepsis in adults. Sepsis was induced in 15-day-old neonatal Sprague-Dawley rats by implanting 0.1 cm3 of fecal pellet impregnated with Escherichia coli (50 CFU) and Bacteroides fragilis (10(3) CFU). Animals receiving fecal pellets without the bacteria were designated as sterile. A group of septic and sterile rats were treated with PGE2 synthesis inhibitors, NS398 and resveratrol. These treatments of animals allowed us to evaluate the role of PGE2 in T-cell suppression during neonatal sepsis. Splenocytes as well as purified T cells were prepared and then proliferative response and IL-2 productive capacities were measured. A significant suppression of splenocyte proliferation and IL-2 production was noticed in both sterile and septic animals compared to the T cells from unoperated control rats. In contrast, the proliferation and IL-2 production by nylon wool purified T cells in sterile rats was not significantly different from control rats, whereas, a significant suppression in Con A-mediated T-cell proliferation and IL-2 production noticed in septic rat T cells compared to the sterile and control rat T cells. Such decrease in T-cell proliferation and IL-2 production was accompanied with 20-25% deaths in neonates implanted with septic pellets. No mortality was noted in sterile-implanted neonates. Treatment of animals with COX-1 inhibitor had no effect on T-cell proliferation response in both septic and sterile groups, whereas COX-2 inhibitor abrogated the decrease in T-cell proliferative response in the septic group. The treatment

  11. Vav1 GEF activity is required for T cell mediated allograft rejection.

    Science.gov (United States)

    Haubert, Dirk; Li, Jianping; Saveliev, Alexander; Calzascia, Thomas; Sutter, Esther; Metzler, Barbara; Kaiser, Daniel; Tybulewicz, Victor L J; Weckbecker, Gisbert

    2012-06-01

    The GDP exchange factor (GEF) Vav1 is a central signal transducer downstream of the T cell receptor and has been identified as a key factor for T cell activation in the context of allograft rejection. Vav1 has been shown to transduce signals both dependent and independent of its GEF function. The most promising approach to disrupt Vav1 activity by pharmacological inhibition would be to target its GEF function. However, the contribution of Vav1 GEF activity for allogeneic T cell activation has not been clarified yet. To address this question, we used knock-in mice bearing a mutated Vav1 with disrupted GEF activity but intact GEF-independent functions. T cells from these mice showed strongly reduced proliferation and activation in response to allogeneic stimulation. Furthermore, lack of Vav1 GEF activity strongly abrogated the in vivo expansion of T cells in a systemic graft-versus-host model. In a cardiac transplantation model, mice with disrupted Vav1 GEF activity show prolonged allograft survival. These findings demonstrate a strong requirement for Vav1 GEF activity for allogeneic T cell activation and graft rejection suggesting that disruption of Vav1 GEF activity alone is sufficient to induce significant immunosuppression. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Sex differences in T cells in hypertension.

    Science.gov (United States)

    Tipton, Ashlee J; Sullivan, Jennifer C

    2014-12-01

    Hypertension is a major risk factor for cardiovascular disease, stroke, and end-organ damage. There is a sex difference in blood pressure (BP) that begins in adolescence and continues into adulthood, in which men have a higher prevalence of hypertension compared with women until the sixth decade of life. Less than 50% of hypertensive adults in the United States manage to control their BP to recommended levels using current therapeutic options, and women are more likely than are men to have uncontrolled high BP. This, is despite the facts that more women compared with men are aware that they have hypertension and that women are more likely to seek treatment for the disease. Novel therapeutic targets need to be identified in both sexes to increase the percentage of hypertensive individuals with controlled BP. The purpose of this article was to review the available literature on the role of T cells in BP control in both sexes, and the potential therapeutic application/implications of targeting immune cells in hypertension. A search of PubMed was conducted to determine the impact of sex on T cell-mediated control of BP. The search terms included sex, gender, estrogen, testosterone, inflammation, T cells, T regulatory cells, Th17 cells, hypertension, and blood pressure. Additional data were included from our laboratory examinations of cytokine expression in the kidneys of male and female spontaneously hypertensive rats (SHRs) and differential gene expression in both the renal cortex and mesenteric arterial bed of male and female SHRs. There is a growing scientific literature base regarding the role of T cells in the pathogenesis of hypertension and BP control; however, the majority of these studies have been performed exclusively in males, despite the fact that both men and women develop hypertension. There is increasing evidence that although T cells also mediate BP in females, there are distinct differences in both the T-cell profile and the functional impact of sex

  13. Homeostatic T Cell Expansion to Induce Anti-Tumor Autoimmunity in Breast Cancer

    National Research Council Canada - National Science Library

    Baccala, Roberto

    2007-01-01

    ... that (a) homeostatic T-cell proliferation consistently elicits anti-tumor responses; (b) irradiation is more effective than Tcell depletion by antibodies in inducing anti-tumor responses mediated by homeostatic T-cell proliferation...

  14. The ThPOK transcription factor differentially affects the development and function of self-specific CD8(+) T cells and regulatory CD4(+) T cells.

    Science.gov (United States)

    Twu, Yuh-Ching; Teh, Hung-Sia

    2014-03-01

    The zinc finger transcription factor ThPOK plays a crucial role in CD4 T-cell development and CD4/CD8 lineage decision. In ThPOK-deficient mice, developing T cells expressing MHC class II-restricted T-cell receptors are redirected into the CD8 T-cell lineage. In this study, we investigated whether the ThPOK transgene affected the development and function of two additional types of T cells, namely self-specific CD8 T cells and CD4(+) FoxP3(+) T regulatory cells. Self-specific CD8 T cells are characterized by high expression of CD44, CD122, Ly6C, 1B11 and proliferation in response to either IL-2 or IL-15. The ThPOK transgene converted these self-specific CD8 T cells into CD4 T cells. The converted CD4(+) T cells are no longer self-reactive, lose the characteristics of self-specific CD8 T cells, acquire the properties of conventional CD4 T cells and survive poorly in peripheral lymphoid organs. By contrast, the ThPOK transgene promoted the development of CD4(+) FoxP3(+) regulatory T cells resulting in an increased recovery of CD4(+) FoxP3(+) regulatory T cells that expressed higher transforming growth factor-β-dependent suppressor activity. These studies indicate that the ThPOK transcription factor differentially affects the development and function of self-specific CD8 T cells and CD4(+) FoxP3(+) regulatory T cells. © 2013 John Wiley & Sons Ltd.

  15. Fentanyl Suppresses the Survival of CD4+ T Cells Isolated from Human Umbilical Cord Blood through Inhibition of IKKs-mediated NF-κB Activation.

    Science.gov (United States)

    Ma, K; Ma, P; Lu, H; Liu, S; Cao, Q

    2017-05-01

    The aim of this study was to investigate the effects and the underlying mechanisms of fentanyl anaesthetic on T lymphocytes isolated from human umbilical cord blood in vitro. The percentages of CD4 + , CD8 + and regulatory T (Treg) cells in human umbilical cord blood mononuclear cells (UBMC) treated with fentanyl in vitro were analysed by flow cytometry. The levels of cytokines IFN-γ, IL-2, IL-4 and IL-17 secreted by activated CD4 + T cells were measured by ELISA assays. Expressions of MAPK and NF-κB signalling pathway proteins were determined by Western blotting. Effects of fentanyl on IKK and p65 expression promoter activities were analysed by luciferase assay. Fentanyl decreased the percentages and amounts of CD4 + , CD8 + and Foxp3 + Treg T lymphocyte subsets in UBMCs in a dose-dependent manner. Fentanyl inhibited the proliferation and induced apoptosis of activated CD4 + T cells dose dependently. Fentanyl could not reverse the increase of cell proliferation in activated groups to be equivalent with those in inactivated group. Secretions of IFN-γ, IL-2 and IL-4 cytokines were significantly decreased by moderate to high dose of fentanyl compared with controls. No significant differences were observed in protein expressions of MAPK pathway. In addition, fentanyl suppressed the IKKs-mediated activation of NF-κB. This study demonstrates that fentanyl exerts immunosuppressive effects on T lymphocytes obtained from UBMCs. Thus, the clinical application of fentanyl would not only relieve pain caused by surgery but regulate immune responses post-operation possibly through inhibition of IKKs-mediated NF-κB activation. © 2017 The Foundation for the Scandinavian Journal of Immunology.

  16. Induction of cell death by graphene in Arabidopsis thaliana (Columbia ecotype) T87 cell suspensions

    International Nuclear Information System (INIS)

    Begum, Parvin; Fugetsu, Bunshi

    2013-01-01

    Highlights: • This study was set up to explore potential influence of graphene on T87 cells. • Fragmented nuclei, membrane damage, mitochondrial dysfunction were observed. • ROS increased, ROS are key mediators in the cell death signaling pathway. • Translocation of graphene into cells and an endocytosis-like structure was observed. • Graphene entering into the cells by endocytosis. -- Abstract: The toxicity of graphene on suspensions of Arabidopsis thaliana (Columbia ecotype) T87 cells was investigated by examining the morphology, mitochondrial dysfunction, reactive oxygen species generation (ROS), and translocation of graphene as the toxicological endpoints. The cells were grown in Jouanneau and Péaud-Lenoel (JPL) media and exposed to graphene at concentrations 0–80 mg/L. Morphological changes were observed by scanning electron microscope and the adverse effects such as fragmented nuclei, membrane damage, mitochondrial dysfunction was observed with fluorescence microscopy by staining with Hoechst 33342/propidium iodide and succinate dehydrogenase (mitochondrial bioenergetic enzyme). Analysis of intracellular ROS by 2′,7′-dichlorofluorescein diacetate demonstrated that graphene induced a 3.3-fold increase in ROS, suggesting that ROS are key mediators in the cell death signaling pathway. Transmission electron microscopy verified the translocation of graphene into cells and an endocytosis-like structure was observed which suggested graphene entering into the cells by endocytosis. In conclusion, our results show that graphene induced cell death in T87 cells through mitochondrial damage mediated by ROS

  17. Impact of nicotine on the interplay between human periodontal ligament cells and CD4+ T cells.

    Science.gov (United States)

    Ge, Xin; Liu, Ying-Feng; Wong, Yong; Wu, Li-Zheng; Tan, Ling; Liu, Fen; Wang, Xiao-Jing

    2016-09-01

    Periodontitis is a common infectious disease associated with destruction of periodontal ligaments and alveolar bones. CD4(+) T cell-mediated immune response is involved in the progression of periodontitis. Tobacco consumption increases the risk of periodontal disease. However, the impact of nicotine on the interaction between human periodontal ligament (PDL) cells and CD4(+) T cells remains unrevealed. Our study aims to investigate the effect of nicotine on PDL cells and the cocultured CD4(+) T cells. The PDL cell cultures were established by explants from healthy individuals, exposed to nicotine or α-bungarotoxin (α-BTX), and incubated solely or in combination with CD4(+) T cells. Afterwards, cell viability, secreted cytokines, and matrix metalloproteinases (MMPs) were evaluated. In monoculture of PDL cells, nicotine dramatically repressed cell viability and increased apoptosis. Meanwhile, α-BTX largely reversed the nicotine-induced apoptosis and increased viability of PDL cells. Compared with the monoculture, MMP-1, MMP-3, interleukin (IL)-1β, IL-6, IL-17, and IL-21 in supernatant of cocultures were markedly elevated after treatment with nicotine. Moreover, α-BTX significantly attenuated nicotine-triggered production of these components either in mono- or co-cultures. In addition, PDL cell-derived CXCL12 following nicotine treatment recruited CD4(+) T cells. Above all, nicotine deteriorated periodontitis partially by promoting PDL cell-CD4(+) T cell-mediated inflammatory response and matrix degradation. © The Author(s) 2015.

  18. Flow cytometric analysis of regulatory T cells during hyposensitization of acquired allergic contact dermatitis.

    Science.gov (United States)

    Fraser, Kathleen; Abbas, Mariam; Hull, Peter R

    2014-01-01

    We previously demonstrated that repeated intradermal steroid injections administered at weekly intervals into positive patch-test sites induce hyposensitization and desensitization. To examine changes in CD4CD25CD127lo/ regulatory T cells during the attenuation of the patch-test response. Ten patients with known allergic contact dermatitis were patch tested weekly for 10 weeks. The patch-test site was injected intradermally with 2 mg triamcinolone. At weeks 1 and 7, a biopsy was performed on the patch-test site in 6 patients, and flow cytometry was performed assessing CD4CD25CD127lo/ regulatory T cells. Secondary outcomes were clinical score, reaction size, erythema, and temperature. Statistical analysis included regression, correlation, and repeated-measures analysis of variance. The percentage of CD4CD25CD127lo/ regulatory T cells, measured by flow cytometry, increased from week 1 to week 7 by an average of 19.2%. The average grade of patch-test reaction decreased from +++ (vesicular reaction) to ++ (palpable erythema). The mean drop in temperature following treatment was 0.28°C per week. The mean area decreased 8.6 mm/wk over 10 weeks. Intradermal steroid injections of weekly patch-test reactions resulted in hyposensitization of the allergic contact dermatitis reaction. CD4CD25CD127lo/ regulatory T cells showed a tendency to increase; however, further studies are needed to determine if this is significant.

  19. T Cell-Mediated Beta Cell Destruction: Autoimmunity and Alloimmunity in the Context of Type 1 Diabetes

    Directory of Open Access Journals (Sweden)

    Adam L. Burrack

    2017-12-01

    Full Text Available Type 1 diabetes (T1D results from destruction of pancreatic beta cells by T cells of the immune system. Despite improvements in insulin analogs and continuous blood glucose level monitoring, there is no cure for T1D, and some individuals develop life-threatening complications. Pancreas and islet transplantation have been attractive therapeutic approaches; however, transplants containing insulin-producing cells are vulnerable to both recurrent autoimmunity and conventional allograft rejection. Current immune suppression treatments subdue the immune system, but not without complications. Ideally a successful approach would target only the destructive immune cells and leave the remaining immune system intact to fight foreign pathogens. This review discusses the autoimmune diabetes disease process, diabetic complications that warrant a transplant, and alloimmunity. First, we describe the current understanding of autoimmune destruction of beta cells including the roles of CD4 and CD8 T cells and several possibilities for antigen-specific tolerance induction. Second, we outline diabetic complications necessitating beta cell replacement. Third, we discuss transplant recognition, potential sources for beta cell replacement, and tolerance-promoting therapies under development. We hypothesize that a better understanding of autoreactive T cell targets during disease pathogenesis and alloimmunity following transplant destruction could enhance attempts to re-establish tolerance to beta cells.

  20. Networked T cell death following macrophage infection by Mycobacterium tuberculosis.

    Directory of Open Access Journals (Sweden)

    Stephen H-F Macdonald

    Full Text Available BACKGROUND: Depletion of T cells following infection by Mycobacterium tuberculosis (Mtb impairs disease resolution, and interferes with clinical test performance that relies on cell-mediated immunity. A number of mechanisms contribute to this T cell suppression, such as activation-induced death and trafficking of T cells out of the peripheral circulation and into the diseased lungs. The extent to which Mtb infection of human macrophages affects T cell viability however, is not well characterised. METHODOLOGY/PRINCIPAL FINDINGS: We found that lymphopenia (<1.5 × 10(9 cells/l was prevalent among culture-positive tuberculosis patients, and lymphocyte counts significantly improved post-therapy. We previously reported that Mtb-infected human macrophages resulted in death of infected and uninfected bystander macrophages. In the current study, we sought to examine the influence of infected human alveolar macrophages on T cells. We infected primary human alveolar macrophages (the primary host cell for Mtb or PMA-differentiated THP-1 cells with Mtb H37Ra, then prepared cell-free supernatants. The supernatants of Mtb-infected macrophages caused dose-dependent, caspase-dependent, T cell apoptosis. This toxic effect of infected macrophage secreted factors did not require TNF-α or Fas. The supernatant cytotoxic signal(s were heat-labile and greater than 50 kDa in molecular size. Although ESAT-6 was toxic to T cells, other Mtb-secreted factors tested did not influence T cell viability; nor did macrophage-free Mtb bacilli or broth from Mtb cultures. Furthermore, supernatants from Mycobacterium bovis Bacille de Calmette et Guerin (BCG- infected macrophages also elicited T cell death suggesting that ESAT-6 itself, although cytotoxic, was not the principal mediator of T cell death in our system. CONCLUSIONS: Mtb-Infected macrophages secrete heat-labile factors that are toxic to T cells, and may contribute to the immunosuppression seen in tuberculosis as well as

  1. Selective destruction of mouse islet beta cells by human T lymphocytes in a newly-established humanized type 1 diabetic model

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yong, E-mail: yongzhao@uic.edu [Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612 (United States); Guo, Chengshan; Hwang, David; Lin, Brian; Dingeldein, Michael; Mihailescu, Dan; Sam, Susan; Sidhwani, Seema [Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612 (United States); Zhang, Yongkang [Department of Pharmacology, University of Illinois at Chicago, Chicago, IL 60612 (United States); Jain, Sumit [Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612 (United States); Skidgel, Randal A. [Department of Pharmacology, University of Illinois at Chicago, Chicago, IL 60612 (United States); Prabhakar, Bellur S. [Department of Immunology and Microbiology, University of Illinois at Chicago, Chicago, IL 60612 (United States); Mazzone, Theodore [Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612 (United States); Holterman, Mark J. [Department of Surgery, University of Illinois at Chicago, Chicago, IL 60612 (United States)

    2010-09-03

    Research highlights: {yields} Establish a human immune-mediated type 1 diabetic model in NOD-scid IL2r{gamma}{sup null} mice. {yields} Using the irradiated diabetic NOD mouse spleen mononuclear cells as trigger. {yields} The islet {beta} cells were selectively destroyed by infiltrated human T cells. {yields} The model can facilitate translational research to find a cure for type 1 diabetes. -- Abstract: Type 1 diabetes (T1D) is caused by a T cell-mediated autoimmune response that leads to the loss of insulin-producing {beta} cells. The optimal preclinical testing of promising therapies would be aided by a humanized immune-mediated T1D model. We develop this model in NOD-scid IL2r{gamma}{sup null} mice. The selective destruction of pancreatic islet {beta} cells was mediated by human T lymphocytes after an initial trigger was supplied by the injection of irradiated spleen mononuclear cells (SMC) from diabetic nonobese diabetic (NOD) mice. This resulted in severe insulitis, a marked loss of total {beta}-cell mass, and other related phenotypes of T1D. The migration of human T cells to pancreatic islets was controlled by the {beta} cell-produced highly conserved chemokine stromal cell-derived factor 1 (SDF-1) and its receptor C-X-C chemokine receptor (CXCR) 4, as demonstrated by in vivo blocking experiments using antibody to CXCR4. The specificity of humanized T cell-mediated immune responses against islet {beta} cells was generated by the local inflammatory microenvironment in pancreatic islets including human CD4{sup +} T cell infiltration and clonal expansion, and the mouse islet {beta}-cell-derived CD1d-mediated human iNKT activation. The selective destruction of mouse islet {beta} cells by a human T cell-mediated immune response in this humanized T1D model can mimic those observed in T1D patients. This model can provide a valuable tool for translational research into T1D.

  2. Tyrosine kinase inhibitors as modulators of trastuzumab-mediated antibody-dependent cell-mediated cytotoxicity in breast cancer cell lines.

    Science.gov (United States)

    Collins, Denis M; Gately, Kathy; Hughes, Clare; Edwards, Connla; Davies, Anthony; Madden, Stephen F; O'Byrne, Kenneth J; O'Donovan, Norma; Crown, John

    2017-09-01

    Trastuzumab is an anti-HER2 monoclonal antibody (mAb) therapy capable of antibody-dependent cell-mediated cytotoxicity (ADCC) and used in the treatment of HER2+ breast cancer. Through interactions with FcƴR+ immune cell subsets, trastuzumab functions as a passive immunotherapy. The EGFR/HER2-targeting tyrosine kinase inhibitor (TKI) lapatinib and the next generation TKIs afatinib and neratinib, can alter HER2 levels, potentially modulating the ADCC response to trastuzumab. Using LDH-release assays, we investigated the impact of antigen modulation, assay duration and peripheral blood mononuclear cell (PBMC) activity on trastuzumab-mediated ADCC in breast cancer models of maximal (SKBR3) and minimal (MCF-7) target antigen expression to determine if modulating the ADCC response to trastuzumab using TKIs may be a viable approach for enhancing tumor immune reactivity. HER2 levels were determined in lapatinib, afatinib and neratinib-treated SKBR3 and MCF-7 using high content analysis (HCA). Trastuzumab-mediated ADCC was assessed following treatment with TKIs utilising a colorimetric LDH release-based protocol at 4 and 12h timepoints. PBMC activity was assessed against non-MHC-restricted K562 cells. A flow cytometry-based method (CFSE/7-AAD) was also used to measure trastuzumab-mediated ADCC in medium-treated SKBR3 and MCF-7. HER2 antigen levels were significantly altered by the three TKIs in both cell line models. The TKIs significantly reduced LDH levels directly in SKBR3 cells but not MCF-7. Lapatinib and neratinib augment trastuzumab-related ADCC in SKBR3 but the effect was not consistent with antigen expression levels and was dependent on volunteer PBMC activity (vs. K562). A 12h assay timepoint produced more consistent results. Trastuzumab-mediated ADCC (PBMC:target cell ratio of 10:1) was measured at 7.6±4.7% (T12) by LDH assay and 19±3.2 % (T12) using the flow cytometry-based method in the antigen-low model MCF-7. In the presence of effector cells with high

  3. Recruitment of Mediator Complex by Cell Type and Stage-Specific Factors Required for Tissue-Specific TAF Dependent Gene Activation in an Adult Stem Cell Lineage.

    Directory of Open Access Journals (Sweden)

    Chenggang Lu

    2015-12-01

    Full Text Available Onset of terminal differentiation in adult stem cell lineages is commonly marked by robust activation of new transcriptional programs required to make the appropriate differentiated cell type(s. In the Drosophila male germ line stem cell lineage, the switch from proliferating spermatogonia to spermatocyte is accompanied by one of the most dramatic transcriptional changes in the fly, as over 1000 new transcripts turn on in preparation for meiosis and spermatid differentiation. Here we show that function of the coactivator complex Mediator is required for activation of hundreds of new transcripts in the spermatocyte program. Mediator appears to act in a sequential hierarchy, with the testis activating Complex (tMAC, a cell type specific form of the Mip/dREAM general repressor, required to recruit Mediator subunits to the chromatin, and Mediator function required to recruit the testis TAFs (tTAFs, spermatocyte specific homologs of subunits of TFIID. Mediator, tMAC and the tTAFs co-regulate expression of a major set of spermatid differentiation genes. The Mediator subunit Med22 binds the tMAC component Topi when the two are coexpressed in S2 cells, suggesting direct recruitment. Loss of Med22 function in spermatocytes causes meiosis I maturation arrest male infertility, similar to loss of function of the tMAC subunits or the tTAFs. Our results illuminate how cell type specific versions of the Mip/dREAM complex and the general transcription machinery cooperate to drive selective gene activation during differentiation in stem cell lineages.

  4. The phosphorylation state of CD3gamma influences T cell responsiveness and controls T cell receptor cycling

    DEFF Research Database (Denmark)

    Dietrich, J; Backstrom, T; Lauritsen, JP

    1998-01-01

    The T cell receptor (TCR) is internalized following activation of protein kinase C (PKC) via a leucine (Leu)-based motif in CD3gamma. Some studies have indicated that the TCR is recycled back to the cell surface following PKC-mediated internalization. The functional state of recycled TCR...... the phosphorylation state of CD3gamma and T cell responsiveness. Based on these observations a physiological role of CD3gamma and TCR cycling is proposed....... and the mechanisms involved in the sorting events following PKC-induced internalization are not known. In this study, we demonstrated that following PKC-induced internalization, the TCR is recycled back to the cell surface in a functional state. TCR recycling was dependent on dephosphorylation of CD3gamma, probably...

  5. Increased numbers of pre-existing memory CD8 T cells and decreased T-bet expression can restrain terminal differentiation of secondary effector and memory CD8 T cells1

    Science.gov (United States)

    Joshi, Nikhil S.; Cui, Weiguo; Dominguez, Claudia; Chen, Jonathan H.; Hand, Timothy W.; Kaech, Susan M.

    2011-01-01

    Memory CD8 T cells acquire TEM properties following reinfection, and may reach terminally differentiated, senescent states (“Hayflick limit”) after multiple infections. The signals controlling this process are not well understood, but we found that the degree of 2o effector and memory CD8 T cell differentiation was intimately linked to the amount of T-bet expressed upon reactivation and pre-existing memory CD8 T cell number (i.e., 1o memory CD8 T cell precursor frequency) present during secondary infection. Compared to naïve cells, memory CD8 T cells were predisposed towards terminal effector (TE) cell differentiation because they could immediately respond to IL-12 and induce T-bet, even in the absence of antigen. TE cell formation following 2o or 3o infections was dependent on increased T-bet expression because T-bet+/− cells were resistant to these phenotypic changes. Larger numbers of pre-existing memory CD8 T cells limited the duration of 2o infection and the amount of IL-12 produced, and consequently, this reduced T-bet expression and the proportion of 2o TE CD8 T cells that formed. Together, these data show that, over repeated infections, memory CD8 T cell quality and proliferative fitness is not strictly determined by the number of serial encounters with antigen or cell divisions, but is a function of the CD8 T cell differentiation state, which is genetically controlled in a T-bet-dependent manner. This differentiation state can be modulated by pre-existing memory CD8 T cell number and the intensity of inflammation during reinfection. These results have important implications for vaccinations involving prime-boost strategies. PMID:21930973

  6. Overcoming acquired drug resistance in colorectal cancer cells by targeted delivery of 5-FU with EGF grafted hollow mesoporous silica nanoparticles

    Science.gov (United States)

    Chen, Lijue; She, Xiaodong; Wang, Tao; He, Li; Shigdar, Sarah; Duan, Wei; Kong, Lingxue

    2015-08-01

    Acquired drug resistance (ADR) can be developed in colorectal cancer cells after 5-fluorouracil (5-FU) treatment and diminish the effectiveness of chemotherapy. In this work, acquired 5-FU resistance in the colorectal cancer cell line SW480 was obtained with the up-regulation of dihydropyrimidine dehydrogenase (DPYD) gene expression which can convert 5-FU to its inactive metabolite. To overcome ADR in colorectal cancer, hollow mesoporous silica nanoparticles (HMSNs) grafted with epidermal growth factor (EGF) were used as nanocarriers to deliver 5-FU to colorectal cancer cells with acquired drug resistance. The effect and mechanism of 5-FU loaded EGF grafted HMSNs (EGF-HMSNs-5-FU) in overcoming acquired drug resistance in SW480/ADR cells were studied. The EGF-HMSNs were demonstrated to be specifically internalized in EGFR overexpressed SW480/ADR cells via a receptor-mediated endocytosis and can escape from endo-lysosomes. The EGF-HMSNs-5-FU exhibited much higher cytotoxicity on SW480/ADR cells than HMSNs-5-FU and free 5-FU while the plain HMSNs did not show significant cytotoxicity. The mechanism of EGF-HMSNs-5-FU in overcoming drug resistance in SW480/ADR cells could be attributed to the specific internalization of EGF-HMSNs-5-FU in EGFR overexpressed cells which can lead to high intracellular drug accumulation and cause cell death through S phase arrest.Acquired drug resistance (ADR) can be developed in colorectal cancer cells after 5-fluorouracil (5-FU) treatment and diminish the effectiveness of chemotherapy. In this work, acquired 5-FU resistance in the colorectal cancer cell line SW480 was obtained with the up-regulation of dihydropyrimidine dehydrogenase (DPYD) gene expression which can convert 5-FU to its inactive metabolite. To overcome ADR in colorectal cancer, hollow mesoporous silica nanoparticles (HMSNs) grafted with epidermal growth factor (EGF) were used as nanocarriers to deliver 5-FU to colorectal cancer cells with acquired drug resistance. The

  7. T cell recognition of breast cancer antigens

    DEFF Research Database (Denmark)

    Petersen, Nadia Viborg; Andersen, Sofie Ramskov; Andersen, Rikke Sick

    Recent studies are encouraging research of breast cancer immunogenicity to evaluate the applicability ofimmunotherapy as a treatment strategy. The epitope landscape in breast cancer is minimally described, thus it is necessary to identify T cell targets to develop immune mediated therapies.......This project investigates four proteins commonly upregulated in breast cancer and thus probable tumor associated antigens (TAAs). Aromatase, prolactin, NEK3, and PIAS3 contribute to increase growth, survival, and motility of malignant cells. Aspiring to uncover novel epitopes for cytotoxic T cells, a reverse...... recognition utilizing DNA barcode labeled MHC multimers to screen peripheral blood lymphocytes from breast cancer patients and healthy donor samples. Signif-icantly more TAA specific T cell responses were detected in breast cancer patients than healthy donors for both HLA-A*0201 (P

  8. Modulation of Memory T Cells to Control Acquired Bone Marrow Failure

    Science.gov (United States)

    2016-01-01

    generation of T helper (Th)1 and Th17 cells, which are characterized by producing high levels of IFN-γ and IL-17, respectively.33-36 This leads to...with advanced professional skills and experience assist others in attaining greater proficiency. Training activities may include, for example, courses...or one-on-one work with a mentor. “Professional development” activities result in increased knowledge or skill in one’s area of expertise and may

  9. Toward precision manufacturing of immunogene T-cell therapies.

    Science.gov (United States)

    Xu, Jun; Melenhorst, J Joseph; Fraietta, Joseph A

    2018-05-01

    Cancer can be effectively targeted using a patient's own T cells equipped with synthetic receptors, including chimeric antigen receptors (CARs) that redirect and reprogram these lymphocytes to mediate tumor rejection. Over the past two decades, several strategies to manufacture genetically engineered T cells have been proposed, with the goal of generating optimally functional cellular products for adoptive transfer. Based on this work, protocols for manufacturing clinical-grade CAR T cells have been established, but these complex methods have been used to treat only a few hundred individuals. As CAR T-cell therapy progresses into later-phase clinical trials and becomes an option for more patients, a major consideration for academic institutions and industry is developing robust manufacturing processes that will permit scaling-out production of immunogene T-cell therapies in a reproducible and efficient manner. In this review, we will discuss the steps involved in cell processing, the major obstacles surrounding T-cell manufacturing platforms and the approaches for improving cellular product potency. Finally, we will address the challenges of expanding CAR T-cell therapy to a global patient population. Copyright © 2018 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  10. T cells in multiple sclerosis and experimental autoimmune encephalomyelitis.

    LENUS (Irish Health Repository)

    Fletcher, J M

    2012-02-01

    Multiple sclerosis (MS) is a demyelinating inflammatory disorder of the central nervous system (CNS), which involves autoimmune responses to myelin antigens. Studies in experimental autoimmune encephalomyelitis (EAE), an animal model for MS, have provided convincing evidence that T cells specific for self-antigens mediate pathology in these diseases. Until recently, T helper type 1 (Th1) cells were thought to be the main effector T cells responsible for the autoimmune inflammation. However more recent studies have highlighted an important pathogenic role for CD4(+) T cells that secrete interleukin (IL)-17, termed Th17, but also IL-17-secreting gammadelta T cells in EAE as well as other autoimmune and chronic inflammatory conditions. This has prompted intensive study of the induction, function and regulation of IL-17-producing T cells in MS and EAE. In this paper, we review the contribution of Th1, Th17, gammadelta, CD8(+) and regulatory T cells as well as the possible development of new therapeutic approaches for MS based on manipulating these T cell subtypes.

  11. Production of acquired immunodeficiency syndrome-associated retrovirus in human and nonhuman cells transfected with an infectious molecular clone

    International Nuclear Information System (INIS)

    Adachi, A.; Gendelman, H.E.; Koenig, S.; Folks, T.; Willey, R.; Rabson, A.; Martin, M.A.

    1986-01-01

    The authors considered an infectious molecular clone of acquired immunodeficiency syndrome-associated retrovirus. Upon transfection, this clone directed the production of infectious virus particles in a wide variety of cells in addition to human T4 cells. The progeny, infectious virions, were synthesized in mouse, mink, monkey, and several human non-T cell lines, indicating the absence of any intracellular obstacle to viral RNA or protein production or assembly. During the course of these studies, a human colon carcinoma cell line, exquisitely sensitive to DNA transfection, was identified

  12. Activated human T cells secrete exosomes that participate in IL-2 mediated immune response signaling.

    Directory of Open Access Journals (Sweden)

    Jessica Wahlgren

    Full Text Available It has previously been shown that nano-meter sized vesicles (30-100 nm, exosomes, secreted by antigen presenting cells can induce T cell responses thus showing the potential of exosomes to be used as immunological tools. Additionally, activated CD3⁺ T cells can secrete exosomes that have the ability to modulate different immunological responses. Here, we investigated what effects exosomes originating from activated CD3⁺ T cells have on resting CD3⁺ T cells by studying T cell proliferation, cytokine production and by performing T cell and exosome phenotype characterization. Human exosomes were generated in vitro following CD3⁺ T cell stimulation with anti-CD28, anti-CD3 and IL-2. Our results show that exosomes purified from stimulated CD3⁺ T cells together with IL-2 were able to generate proliferation in autologous resting CD3⁺ T cells. The CD3⁺ T cells stimulated with exosomes together with IL-2 had a higher proportion of CD8⁺ T cells and had a different cytokine profile compared to controls. These results indicate that activated CD3⁺ T cells communicate with resting autologous T cells via exosomes.

  13. Alterations in cellular metabolism modulate CD1d-mediated NKT-cell responses.

    Science.gov (United States)

    Webb, Tonya J; Carey, Gregory B; East, James E; Sun, Wenji; Bollino, Dominique R; Kimball, Amy S; Brutkiewicz, Randy R

    2016-08-01

    Natural killer T (NKT) cells play a critical role in the host's innate immune response. CD1d-mediated presentation of glycolipid antigens to NKT cells has been established; however, the mechanisms by which NKT cells recognize infected or cancerous cells remain unclear. 5(')-AMP activated protein kinase (AMPK) is a master regulator of lipogenic pathways. We hypothesized that activation of AMPK during infection and malignancy could alter the repertoire of antigens presented by CD1d and serve as a danger signal to NKT cells. In this study, we examined the effect of alterations in metabolism on CD1d-mediated antigen presentation to NKT cells and found that an infection with lymphocytic choriomeningitis virus rapidly increased CD1d-mediated antigen presentation. Hypoxia inducible factors (HIF) enhance T-cell effector functions during infection, therefore antigen presenting cells pretreated with pharmacological agents that inhibit glycolysis, induce HIF and activate AMPK were assessed for their ability to induce NKT-cell responses. Pretreatment with 2-deoxyglucose, cobalt chloride, AICAR and metformin significantly enhanced CD1d-mediated NKT-cell activation. In addition, NKT cells preferentially respond to malignant B cells and B-cell lymphomas express HIF-1α. These data suggest that targeting cellular metabolism may serve as a novel means of inducing innate immune responses. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Regulation of T cell migration during viral infection: role of adhesion molecules and chemokines

    DEFF Research Database (Denmark)

    Thomsen, Allan Randrup; Nansen, Anneline; Madsen, Andreas Nygaard

    2003-01-01

    T cell mediated immunity and in particular CD8+ T cells are pivotal for the control of most viral infections. T cells exclusively exert their antiviral effect through close cellular interaction with relevant virus-infected target cells in vivo. It is therefore imperative that efficient mechanisms...

  15. NKp46+CD3+ cells - a novel non-conventional T-cell subset in cattle exhibiting both NK cell and T-cell features

    Science.gov (United States)

    Connelley, Timothy K.; Longhi, Cassandra; Burrells, Alison; Degnan, Kathryn; Hope, Jayne; Allan, Alasdair; Hammond, John A.; Storset, Anne K.; Morrison, W. Ivan

    2014-01-01

    The NKp46 receptor demonstrates a high degree of lineage-specificity, being expressed almost exclusively in natural killer cells. Previous studies have demonstrated NKp46 expression by T-cells, but NKp46+CD3+ cells are rare and almost universally associated with NKp46 acquisition by T-cells following stimulation. In this study we demonstrate the existence of a population of NKp46+CD3+ cells resident in normal bovine PBMC which include cells of both the αβ TCR+ and γδ TCR+ lineages and is present at a frequency of 0.1-1.7%. NKp46+CD3+ cells express transcripts for a broad repertoire of both natural killer (NKR) and T-cell receptors (TCR) and also the CD3ζ, DAP10 and FcεR1γ but not DAP12 adaptor proteins. In vitro functional analysis of NKp46+CD3+ cells confirm that NKp46, CD16 and CD3 signalling pathways are all functionally competent and capable of mediating-re-direct cytolysis. However, only CD3 cross-ligation elicits IFN-γ release. NKp46+CD3+ cells exhibit cytotoxic activity against autologous Theileria parva infected cells in vitro and during in vivo challenge with this parasite an expansion of NKp46+CD3+ cells was observed in some animals, indicating the cells have the potential to act as an anti-pathogen effector population. The results presented herein identifies and describes a novel non-conventional NKp46+CD3+ T-cell subset that is phenotypically and functionally distinct from conventional NK and T-cells. The ability to exploit both NKR and TCR suggests these cells may fill a functional niche at the interface of innate and adaptive immune responses. PMID:24639352

  16. The cathepsin B inhibitor z-FA-CMK induces cell death in leukemic T cells via oxidative stress.

    Science.gov (United States)

    Liow, K Y; Chow, Sek C

    2018-01-01

    The cathepsin B inhibitor benzyloxycarbonyl-phenylalanine-alanine-chloromethyl ketone (z-FA-CMK) was recently found to induce apoptosis at low concentrations in Jurkat T cells, while at higher concentrations, the cells die of necrosis. In the present study, we showed that z-FA-CMK readily depletes intracellular glutathione (GSH) with a concomitant increase in reactive oxygen species (ROS) generation. The toxicity of z-FA-CMK in Jurkat T cells was completely abrogated by N-acetylcysteine (NAC), suggesting that the toxicity mediated by z-FA-CMK is due to oxidative stress. We found that L-buthionine sulfoximine (BSO) which depletes intracellular GSH through the inhibition of GSH biosynthesis in Jurkat T cells did not promote ROS increase or induce cell death. However, NAC was still able to block z-FA-CMK toxicity in Jurkat T cells in the presence of BSO, indicating that the protective effect of NAC does not involve GSH biosynthesis. This is further corroborated by the protective effect of the non-metabolically active D-cysteine on z-FA-CMK toxicity. Furthermore, in BSO-treated cells, z-FA-CMK-induced ROS increased which remains unchanged, suggesting that the depletion of GSH and increase in ROS generation mediated by z-FA-CMK may be two separate events. Collectively, our results demonstrated that z-FA-CMK toxicity is mediated by oxidative stress through the increase in ROS generation.

  17. Narcolepsy Type 1 Is Associated with a Systemic Increase and Activation of Regulatory T Cells and with a Systemic Activation of Global T Cells.

    Science.gov (United States)

    Lecendreux, Michel; Churlaud, Guillaume; Pitoiset, Fabien; Regnault, Armelle; Tran, Tu Anh; Liblau, Roland; Klatzmann, David; Rosenzwajg, Michelle

    2017-01-01

    Narcolepsy is a rare neurologic disorder characterized by excessive daytime sleepiness, cataplexy and disturbed nocturnal sleep patterns. Narcolepsy type 1 (NT1) has been shown to result from a selective loss of hypothalamic hypocretin-secreting neurons with patients typically showing low CSF-hypocretin levels (NT1 could be an immune-mediated pathology. Moreover, susceptibility to NT1 has recently been associated with several pathogens, particularly with influenza A H1N1 virus either through infection or vaccination. The goal of this study was to compare peripheral blood immune cell populations in recent onset pediatric NT1 subjects (post or non-post 2009-influenza A H1N1 vaccination) to healthy donors. We demonstrated an increased number of central memory CD4+ T cells (CD62L+ CD45RA-) associated to an activated phenotype (increase in CD69 and CD25 expression) in NT1 patients. Percentage and absolute count of regulatory T cells (Tregs) in NT1 patients were increased associated with an activated phenotype (increase in GITR and LAP expression), and of activated memory phenotype. Cytokine production by CD4+ and CD8+ T cells after activation was not modified in NT1 patients. In H1N1 vaccinated NT1 patients, absolute counts of CD3+, CD8+ T cells, and B cells were increased compared to non-vaccinated NT1 patients. These results support a global T cell activation in NT1 patients and thus support a T cell-mediated autoimmune origin of NT1, but do not demonstrate the pathological role of H1N1 prophylactic vaccination. They should prompt further studies of T cells, particularly of Tregs (such as suppression and proliferation antigen specific assays, and also T-cell receptor sequencing), in NT1.

  18. Comprehensive Approach for Identifying the T Cell Subset Origin of CD3 and CD28 Antibody-Activated Chimeric Antigen Receptor-Modified T Cells.

    Science.gov (United States)

    Schmueck-Henneresse, Michael; Omer, Bilal; Shum, Thomas; Tashiro, Haruko; Mamonkin, Maksim; Lapteva, Natalia; Sharma, Sandhya; Rollins, Lisa; Dotti, Gianpietro; Reinke, Petra; Volk, Hans-Dieter; Rooney, Cliona M

    2017-07-01

    The outcome of therapy with chimeric Ag receptor (CAR)-modified T cells is strongly influenced by the subset origin of the infused T cells. However, because polyclonally activated T cells acquire a largely CD45RO + CCR7 - effector memory phenotype after expansion, regardless of subset origin, it is impossible to know which subsets contribute to the final T cell product. To determine the contribution of naive T cell, memory stem T cell, central memory T cell, effector memory T cell, and terminally differentiated effector T cell populations to the CD3 and CD28-activated CAR-modified T cells that we use for therapy, we followed the fate and function of individually sorted CAR-modified T cell subsets after activation with CD3 and CD28 Abs (CD3/28), transduction and culture alone, or after reconstitution into the relevant subset-depleted population. We show that all subsets are sensitive to CAR transduction, and each developed a distinct T cell functional profile during culture. Naive-derived T cells showed the greatest rate of proliferation but had more limited effector functions and reduced killing compared with memory-derived populations. When cultured in the presence of memory T cells, naive-derived T cells show increased differentiation, reduced effector cytokine production, and a reduced reproliferative response to CAR stimulation. CD3/28-activated T cells expanded in IL-7 and IL-15 produced greater expansion of memory stem T cells and central memory T cell-derived T cells compared with IL-2. Our strategy provides a powerful tool to elucidate the characteristics of CAR-modified T cells, regardless of the protocol used for expansion, reveals the functional properties of each expanded T cell subset, and paves the way for a more detailed evaluation of the effects of manufacturing changes on the subset contribution to in vitro-expanded T cells. Copyright © 2017 by The American Association of Immunologists, Inc.

  19. Tolerogenic dendritic cells from poorly compensated type 1 diabetes patients have decreased ability to induce stable antigen-specific T cell hyporesponsiveness and generation of suppressive regulatory T cells

    DEFF Research Database (Denmark)

    Dánova, Klara; Grohova, Anna; Strnadova, Pavla

    2017-01-01

    state of patients. tolDCs differentiated from both groups of patients acquired a regulatory phenotype and an anti-inflammatory profile. Interestingly, tolDCs from well-controlled patients expressed higher levels of inhibitory molecules IL-T3 and PD-L1. Additionally, glutamic acid decarboxylase (GAD)65......Tolerogenic dendritic cells (tolDCs) may offer an interesting intervention strategy to re-establish Ag-specific tolerance in autoimmune diseases, including type 1 diabetes (T1D). T1D results from selective destruction of insulin-producing b cells leading to hyperglycemia that, in turn, specifically...... suppressive abilities. The functionality of tolDCs was confirmed in the adoptive transfer model of NOD-SCID mice where tolDCs delayed diabetes onset. These results suggest that metabolic control of T1D affects the functional characteristics of tolDCs and subsequent effector T cell responses. Metabolic control...

  20. A Novel Toll-Like Receptor 9 Agonist, MGN1703, Enhances HIV-1 Transcription and NK Cell-Mediated Inhibition of HIV-1-Infected Autologous CD4+ T Cells.

    Science.gov (United States)

    Offersen, Rasmus; Nissen, Sara Konstantin; Rasmussen, Thomas A; Østergaard, Lars; Denton, Paul W; Søgaard, Ole Schmeltz; Tolstrup, Martin

    2016-05-01

    Toll-like receptor (TLR) agonists are potent enhancers of innate antiviral immunity and may also reverse HIV-1 latency. Therefore, TLR agonists have a potential role in the context of a "shock-and-kill" approach to eradicate HIV-1. Our extensive preclinical evaluation suggests that a novel TLR9 agonist, MGN1703, may indeed perform both functions in an HIV-1 eradication trial. Peripheral blood mononuclear cells (PBMCs) from aviremic HIV-1-infected donors on antiretroviral therapy (ART) that were incubated with MGN1703 ex vivo exhibited increased secretion of interferon alpha (IFN-α) (P= 0.005) and CXCL10 (P= 0.0005) in culture supernatants. Within the incubated PBMC pool, there were higher proportions of CD69-positive CD56(dim)CD16(+)NK cells (P= 0.001) as well as higher proportions of CD107a-positive (P= 0.002) and IFN-γ-producing (P= 0.038) NK cells. Incubation with MGN1703 also increased the proportions of CD69-expressing CD4(+)and CD8(+)T cells. Furthermore, CD4(+)T cells within the pool of MGN1703-incubated PBMCs showed enhanced levels of unspliced HIV-1 RNA (P= 0.036). Importantly, MGN1703 increased the capacity of NK cells to inhibit virus spread within a culture of autologous CD4(+)T cells assessed by using an HIV-1 p24 enzyme-linked immunosorbent assay (ELISA) (P= 0.03). In conclusion, we show that MGN1703 induced strong antiviral innate immune responses, enhanced HIV-1 transcription, and boosted NK cell-mediated suppression of HIV-1 infection in autologous CD4(+)T cells. These findings support clinical testing of MGN1703 in HIV-1 eradication trials. We demonstrate that MGN1703 (a TLR9 agonist currently undergoing phase 3 clinical testing for the treatment of metastatic colorectal cancer) induces potent antiviral responses in immune effector cells from HIV-1-infected individuals on suppressive antiretroviral therapy. The significantly improved safety and tolerability profiles of MGN1703 versus TLR9 agonists of the CpG-oligodeoxynucleotide (CpG-ODN) family

  1. Lysosomal ceramide generated by acid sphingomyelinase triggers cytosolic cathepsin B-mediated degradation of X-linked inhibitor of apoptosis protein in natural killer/T lymphoma cell apoptosis.

    Science.gov (United States)

    Taniguchi, M; Ogiso, H; Takeuchi, T; Kitatani, K; Umehara, H; Okazaki, T

    2015-04-09

    We previously reported that IL-2 deprivation induced acid sphingomyelinase-mediated (ASM-mediated) ceramide elevation and apoptosis in an NK/T lymphoma cell line KHYG-1. However, the molecular mechanism of ASM-ceramide-mediated apoptosis during IL-2 deprivation is poorly understood. Here, we showed that IL-2 deprivation induces caspase-dependent apoptosis characterized by phosphatidylserine externalization, caspase-8, -9, and -3 cleavage, and degradation of X-linked inhibitor of apoptosis protein (XIAP). IL-2 re-supplementation rescued apoptosis via inhibition of XIAP degradation without affecting caspase cleavage. However, IL-2 deprivation induced ceramide elevation via ASM in lysosomes and activated lysosomal cathepsin B (CTSB) but not cathepsin D. A CTSB inhibitor CA-074 Me and knockdown of CTSB inhibited ceramide-mediated XIAP degradation and apoptosis. Inhibition of ceramide accumulation in lysosomes using an ASM inhibitor, desipramine, decreased cytosolic activation of CTSB by inhibiting its transfer into cytosol from the lysosome. Knockdown of ASM also inhibited XIAP degradation and apoptosis. Furthermore, cell permeable N-acetyl sphingosine (C2-ceramide), which increases mainly endogenous d18:1/16:0 and d18:1/24:1 ceramide-like IL-2 deprivation, induced caspase-dependent apoptosis with XIAP degradation through CTSB. These findings suggest that lysosomal ceramide produced by ASM mediates XIAP degradation by activation of cytosolic CTSB and caspase-dependent apoptosis. The ASM-ceramide-CTSB signaling axis is a novel pathway of ceramide-mediated apoptosis in IL-2-deprived NK/T lymphoma cells.

  2. Strong adhesion by regulatory T cells induces dendritic cell cytoskeletal polarization and contact-dependent lethargy.

    Science.gov (United States)

    Chen, Jiahuan; Ganguly, Anutosh; Mucsi, Ashley D; Meng, Junchen; Yan, Jiacong; Detampel, Pascal; Munro, Fay; Zhang, Zongde; Wu, Mei; Hari, Aswin; Stenner, Melanie D; Zheng, Wencheng; Kubes, Paul; Xia, Tie; Amrein, Matthias W; Qi, Hai; Shi, Yan

    2017-02-01

    Dendritic cells are targeted by regulatory T (T reg) cells, in a manner that operates as an indirect mode of T cell suppression. In this study, using a combination of single-cell force spectroscopy and structured illumination microscopy, we analyze individual T reg cell-DC interaction events and show that T reg cells exhibit strong intrinsic adhesiveness to DCs. This increased DC adhesion reduces the ability of contacted DCs to engage other antigen-specific cells. We show that this unusually strong LFA-1-dependent adhesiveness of T reg cells is caused in part by their low calpain activities, which normally release integrin-cytoskeleton linkage, and thereby reduce adhesion. Super resolution imaging reveals that such T reg cell adhesion causes sequestration of Fascin-1, an actin-bundling protein essential for immunological synapse formation, and skews Fascin-1-dependent actin polarization in DCs toward the T reg cell adhesion zone. Although it is reversible upon T reg cell disengagement, this sequestration of essential cytoskeletal components causes a lethargic state of DCs, leading to reduced T cell priming. Our results reveal a dynamic cytoskeletal component underlying T reg cell-mediated DC suppression in a contact-dependent manner. © 2017 Chen et al.

  3. TLR-4 engagement of dendritic cells confers a BST-2/tetherin-mediated restriction of HIV-1 infection to CD4+ T cells across the virological synapse

    Directory of Open Access Journals (Sweden)

    Blanchet Fabien P

    2013-01-01

    Full Text Available Abstract Background Dendritic cells and their subsets, located at mucosal surfaces, are among the first immune cells to encounter disseminating pathogens. The cellular restriction factor BST-2/tetherin (also known as CD317 or HM1.24 potently restricts HIV-1 release by retaining viral particles at the cell surface in many cell types, including primary cells such as macrophages. However, BST-2/tetherin does not efficiently restrict HIV-1 infection in immature dendritic cells. Results We now report that BST-2/tetherin expression in myeloid (myDC and monocyte-derived dendritic cells (DC can be significantly up-regulated by IFN-α treatment and TLR-4 engagement with LPS. In contrast to HeLa or 293T cells, infectious HIV-1 release in immature DC and IFN-α–matured DC was only modestly affected in the absence of Vpu compared to wild-type viruses. Strikingly, immunofluorescence analysis revealed that BST-2/tetherin was excluded from HIV containing tetraspanin-enriched microdomains (TEMs in both immature DC and IFN-α–matured DC. In contrast, in LPS-mediated mature DC, BST-2/tetherin exerted a significant restriction in transfer of HIV-1 infection to CD4+ T cells. Additionally, LPS, but not IFN-α stimulation of immature DC, leads to a dramatic redistribution of cellular restriction factors to the TEM as well as at the virological synapse between DC and CD4+ T cells. Conclusions In conclusion, we demonstrate that TLR-4 engagement in immature DC significantly up-regulates the intrinsic antiviral activity of BST-2/tetherin, during cis-infection of CD4+ T cells across the DC/T cell virological synapse. Manipulating the function and potency of cellular restriction factors such as BST-2/tetherin to HIV-1 infection, has implications in the design of antiviral therapeutic strategies.

  4. Inhibition of CSF-1R supports T-cell mediated melanoma therapy.

    Directory of Open Access Journals (Sweden)

    Marjolein Sluijter

    Full Text Available Tumor associated macrophages (TAM can promote angiogenesis, invasiveness and immunosuppression. The cytokine CSF-1 (or M-CSF is an important factor of TAM recruitment and differentiation and several pharmacological agents targeting the CSF-1 receptor (CSF-1R have been developed to regulate TAM in solid cancers. We show that the kinase inhibitor PLX3397 strongly dampened the systemic and local accumulation of macrophages driven by B16F10 melanomas, without affecting Gr-1(+ myeloid derived suppressor cells. Removal of intratumoral macrophages was remarkably efficient and a modest, but statistically significant, delay in melanoma outgrowth was observed. Importantly, CSF-1R inhibition strongly enhanced tumor control by immunotherapy using tumor-specific CD8 T cells. Elevated IFNγ production by T cells was observed in mice treated with the combination of PLX3397 and immunotherapy. These results support the combined use of CSF-1R inhibition with CD8 T cell immunotherapy, especially for macrophage-stimulating tumors.

  5. T1R3 homomeric sweet taste receptor regulates adipogenesis through Gαs-mediated microtubules disassembly and Rho activation in 3T3-L1 cells.

    Directory of Open Access Journals (Sweden)

    Yosuke Masubuchi

    Full Text Available We previously reported that 3T3-L1 cells express a functional sweet taste receptor possibly as a T1R3 homomer that is coupled to Gs and negatively regulates adipogenesis by a Gαs-mediated but cAMP-independent mechanism. Here, we show that stimulation of this receptor with sucralose or saccharin induced disassembly of the microtubules in 3T3-L1 preadipocytes, which was attenuated by overexpression of the dominant-negative mutant of Gαs (Gαs-G226A. In contrast, overexpression of the constitutively active mutant of Gαs (Gαs-Q227L as well as treatment with cholera toxin or isoproterenol but not with forskolin caused disassembly of the microtubules. Sweetener-induced microtubule disassembly was accompanied by activation of RhoA and Rho-associated kinase (ROCK. This was attenuated with by knockdown of GEF-H1, a microtubule-localized guanine nucleotide exchange factor for Rho GTPase. Furthermore, overexpression of the dominant-negative mutant of RhoA (RhoA-T19N blocked sweetener-induced dephosphorylation of Akt and repression of PPARγ and C/EBPα in the early phase of adipogenic differentiation. These results suggest that the T1R3 homomeric sweet taste receptor negatively regulates adipogenesis through Gαs-mediated microtubule disassembly and consequent activation of the Rho/ROCK pathway.

  6. B cells exposed to enterobacterial components suppress development of experimental colitis

    DEFF Research Database (Denmark)

    Schmidt, Esben Gjerløff Wedebye; Larsen, Hjalte List; Kristensen, Nanna Ny

    2012-01-01

    ). RESULTS: We demonstrate that splenic B cells exposed to ebx produce large amounts of IL-10 in vitro and express CD1d and CD5 previously known to be associated with regulatory B cells. In SCID mice transplanted with colitogenic CD4(+) CD25(-) T cells, co-transfer of ebx-B cells significantly suppressed...... development of colitis. Suppression was dependent on B cell-derived IL-10, as co-transfer of IL-10 knockout ebx-B cells failed to suppress colitis. Ebx-B cell-mediated suppression of colitis was associated with a decrease in interferon gamma (IFN-¿)-producing T(H) 1 cells and increased frequencies of Foxp3......-expressing T cells. CONCLUSIONS: These data demonstrate that splenic B cells exposed to enterobacterial components acquire immunosuppressive functions by which they can suppress development of experimental T cell-mediated colitis in an IL-10-dependent way. (Inflamm Bowel Dis 2011;)....

  7. Flow-cytometric measurement of CD4-8- T cells bearing T-cell receptor αβ chains, 1

    International Nuclear Information System (INIS)

    Kusunoki, Yoichiro; Hirai, Yuko; Kyoizumi, Seishi; Akiyama, Mitoshi.

    1992-09-01

    In this study we detected rare, possibly abnormal, T cells bearing CD3 surface antigen and T-cell receptor (TCR) αβ chains but lacking both CD4 and CD8 antigens (viz., TCRαβ + CD4 - 8 - cells, as determined by flow cytometry). The TCRαβ + CD4 - 8 - T cells were detected at a mean frequency of 0.63 ± 0.35 % (mean ± standard deviation) in peripheral blood TCRαβ + cells of 119 normal persons. Two unusual cases besides the 119 normal persons showed extremely elevated frequencies of TCRαβ + CD4 - 8 - T cells, viz., approximately 5 % to 10 % and 14 % to 19 % in whole TCRαβ + cells. Both individuals were males who were otherwise physiologically quite normal with no history of severe illness, and these high frequencies were also observed in blood samples collected 2 or 8 years prior to the current measurements. The TCRαβ + CD4 - 8 - T cells of the two individuals were found to express mature T-cell markers such as CD2,3, and 5 antigens, as well as natural killer (NK) cell markers, viz., CD11b, 16, 56, and 57 antigens, when peripheral blood lymphocytes were subjected to three-color flow cytometry. Lectin-dependent or redirected antibody-dependent cell-mediated cytotoxicities were observed for both freshly sorted TCRαβ + CD4 - 8 - cells and in vitro established clones. Nevertheless, NK-like activity was not detected. Further, Southern blot analysis of TCRβ and γ genes revealed identical rearrangement patterns for all the TCRαβ + CD4 - 8 - clones established in vitro. These results suggest that the TCRαβ + CD4 - 8 - T cells from these two mean exhibit unique characteristics and proliferate clonally in vivo. (author)

  8. Daikenchuto ameliorates muscle hypercontractility in a murine T-cell-mediated persistent gut motor dysfunction model.

    Science.gov (United States)

    Akiho, Hirotada; Nakamura, Kazuhiko

    2011-01-01

    Low-grade inflammation and immunological alterations are evident in functional gastrointestinal disorders such as irritable bowel syndrome (IBS). We evaluated the effects of daikenchuto (DKT), a pharmaceutical grade Japanese herbal medicine, on the hypercontractility of intestinal smooth muscle persisting after acute inflammation induced by a T-cell-activating anti-CD3 antibody (αCD3). BALB/c mice were injected with αCD3 (12.5 μg, i.p.), and DKT (2.7 g/kg) was administered orally once daily for 1 week. The contraction of isolated small intestinal muscle strips and muscle cells was examined on day 7 after αCD3 injection. The gene and protein expressions in the small intestines were evaluated by real-time PCR and multiplex immunoassays, respectively, on days 1, 3 and 7 after αCD3 injection. αCD3 injection resulted in significant increases in carbachol-evoked contractility in the muscle strips and isolated smooth muscle cells on day 7. DKT ameliorated the αCD3-induced muscle hypercontractility on day 7 in both the muscle strips and smooth muscle cells. αCD3 injection rapidly up- and downregulated the mRNA and protein expressions of pro- and anti-inflammatory cytokines, respectively. Although the influence of DKT on the mRNA expressions was moderate, the protein expressions of IL-13 and IL-17 were significantly decreased. We observed changes in the intestinal muscle contractility in muscle strips and muscle cells following resolution of inflammation in a T-cell-mediated model of enteropathy. The observed modulation of cytokine expression and function by DKT may lead to the development of new pharmacotherapeutic strategies aimed at a wide variety of gut motor dysfunction disorders. Copyright © 2011 S. Karger AG, Basel.

  9. Human T-cell lymphotropic virus type 1 and its oncogenesis

    Institute of Scientific and Technical Information of China (English)

    Lan-lan ZHANG; Jing-yun WEI; Long WANG; Shi-le HUANG; Ji-long CHEN

    2017-01-01

    Human T-cell lymphotropic virus type 1 (HTLV-1) is the etiologic agent of adult T-cell leukemia/lymphoma (ATL),a rapidly progressing clonal malignancy of CD4+ T lymphocytes.Exploring the host-HTLV-1 interactions and the molecular mechanisms underlying HTLV-1-mediated tumorigenesis is critical for developing efficient therapies against the viral infection and associated leukemia/lymphoma.It has been demonstrated to date that several HTLV-1 proteins play key roles in the cellular transformation and immortalization of infected T lymphocytes.Of note,the HTLV-1 oncoprotein Tax inhibits the innate IFN response through interaction with MAVS,STING and RIP1,causing the suppression of TBK1-mediated phosphorylation of IRF3/IRF7.The HTLV-1 protein HBZ disrupts genomic integrity and inhibits apoptosis and autophagy of the target cells.Furthermore,it is revealed that HBZ enhances the proliferation of ATL cells and facilitates evasion of the infected cells from immunosurveillance.These studies provide insights into the molecular mechanisms by which HTLV-1 mediates the formation of cancer as well as useful strategies for the development of new therapeutic interventions against ATL.In this article,we review the recent advances in the understanding of the pathogenesis,the underlying mechanisms,clinical diagnosis and treatment of the disease caused by HTLV-1 infection.In addition,we discuss the future direction for targeting HTLV-1-associated cancers and strategies against HTLV-1.

  10. Cutting edge: CD95 maintains effector T cell homeostasis in chronic immune activation

    NARCIS (Netherlands)

    Arens, Ramon; Baars, Paul A.; Jak, Margot; Tesselaar, Kiki; van der Valk, Martin; van Oers, Marinus H. J.; van Lier, René A. W.

    2005-01-01

    The elimination of activated T cells is important to maintain homeostasis and avoid immunopathology. CD95 (Fas/APO-1) has been identified as a death mediator for activated T cells in vitro but the function of CD95 in death of mature T cells in vivo is still controversial. Here we show that

  11. Selective induction of DNA repair pathways in human B cells activated by CD4+ T cells.

    Directory of Open Access Journals (Sweden)

    Xiaosheng Wu

    Full Text Available Greater than 75% of all hematologic malignancies derive from germinal center (GC or post-GC B cells, suggesting that the GC reaction predisposes B cells to tumorigenesis. Because GC B cells acquire expression of the highly mutagenic enzyme activation-induced cytidine deaminase (AID, GC B cells may require additional DNA repair capacity. The goal of this study was to investigate whether normal human B cells acquire enhanced expression of DNA repair factors upon AID induction. We first demonstrated that several DNA mismatch repair, homologous recombination, base excision repair, and ATR signaling genes were overexpressed in GC B cells relative to naïve and memory B cells, reflecting activation of a process we have termed somatic hyperrepair (SHR. Using an in vitro system, we next characterized activation signals required to induce AID expression and SHR. Although AID expression was induced by a variety of polyclonal activators, SHR induction strictly required signals provided by contact with activated CD4+ T cells, and B cells activated in this manner displayed reduced levels of DNA damage-induced apoptosis. We further show the induction of SHR is independent of AID expression, as GC B cells from AID-/-mice retained heightened expression of SHR proteins. In consideration of the critical role that CD4+ T cells play in inducing the SHR process, our data suggest a novel role for CD4+ T cells in the tumor suppression of GC/post-GC B cells.

  12. Donor T cells primed on leukemia lysate-pulsed recipient APCs mediate strong graft-versus-leukemia effects across MHC barriers in full chimeras

    OpenAIRE

    Ghosh, Arnab; Koestner, Wolfgang; Hapke, Martin; Schlaphoff, Verena; Länger, Florian; Baumann, Rolf; Koenecke, Christian; Cornberg, Markus; Welte, Karl; Blazar, Bruce R.; Sauer, Martin G.

    2009-01-01

    Antigen-presenting cells (APCs) of host origin drive graft-versus-leukemia (GVL) effects but can also trigger life-threatening graft-versus-host disease (GVHD) after hematopoietic cell transplantation (HCT) across major histocompatibility complex (MHC) barriers. We show that in vitro priming of donor lymphocytes can circumvent the need of recipient-derived APCs in vivo for mediating robust GVL effects and significantly diminishes the risk of severe GVHD. In vitro, generated and expanded T cel...

  13. FasL Mediates T-Cell Eradication of Tumor Cells Presenting Low Levels of Antigens | Center for Cancer Research

    Science.gov (United States)

    One approach to cancer immunotherapy, as opposed to therapeutic vaccination, is the transfusion of large numbers of tumor-specific killer T cells (cytotoxic T cells or CTLs) into patients. The body’s own defense killer T cells are a subgroup of T lymphocytes (a type of white blood cells) that are capable of inducing death in tumor cells. CTLs can cause the death of target cells either by releasing granules containing toxic molecules including perforin, or by producing a membrane protein called Fas ligand (FasL) which on interaction with the tumor cell results in cell death.

  14. Lysosomal ceramide generated by acid sphingomyelinase triggers cytosolic cathepsin B-mediated degradation of X-linked inhibitor of apoptosis protein in natural killer/T lymphoma cell apoptosis

    OpenAIRE

    Taniguchi, M; Ogiso, H; Takeuchi, T; Kitatani, K; Umehara, H; Okazaki, T

    2015-01-01

    We previously reported that IL-2 deprivation induced acid sphingomyelinase-mediated (ASM-mediated) ceramide elevation and apoptosis in an NK/T lymphoma cell line KHYG-1. However, the molecular mechanism of ASM?ceramide-mediated apoptosis during IL-2 deprivation is poorly understood. Here, we showed that IL-2 deprivation induces caspase-dependent apoptosis characterized by phosphatidylserine externalization, caspase-8, -9, and -3 cleavage, and degradation of X-linked inhibitor of apoptosis pro...

  15. Chemokine receptors CCR6 and CXCR3 are necessary for CD4(+) T cell mediated ocular surface disease in experimental dry eye disease.