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1.
BACKGROUND: Recently, it has been established that CD4(+)CD25(+) T cells with regulatory capacity are present in human peripheral blood, inhibiting allogeneic proliferation and cytokine production of preactivated CD4(+)CD25(-) respond-er T cells. OBJECTIVE: The aim of this study was to analyze in an allergen-specific setting whether such regulatory CD4(+)CD25(+) T cells also exist and function normally in atopic individuals, especially concerning the inhibition of T(H)2 cytokines. METHODS: For this purpose, CD4(+)CD25(-) or CD4(+)CD25(+) T cells from donors allergic to grass or birch pollen (mainly with rhinitis) or from healthy nonatopic donors were stimulated in the presence of autologous, mature, monocyte-derived, allergen-pulsed dendritic cells, and the preactivated CD4(+)CD25(+) T cells were added to CD4(+)CD25(-) T cells during restimulation. RESULTS: CD4(+)CD25(+) T cells from the nonatopic donors and from the majority of the patients investigated proliferated poorly, produced fewer cytokines, and inhibited the proliferation and T(H)1 (IFN-gamma) and T(H)2 (IL-4 and IL-5) cytokine production of CD4(+)CD25(-) T cells but not IL-10 production. The suppression of CD4(+)CD25(-) T cells by CD4(+)CD25(+) T cells was at least partially antigen unspecific and not reversible with anti-IL-10, anti-transforming growth factor beta, or anti-cytotoxic T lymphocyte-associated antigen 4 mAb but was reversible with IL-2. In some atopic patients preactivated CD4(+)CD25(+) T cells reproducibly showed strong proliferative responses, produced higher amounts of IL-4 and IL-10 than CD4(+)CD25(-) T cells, and suppressed only the IFN-gamma production of CD4(+)CD25(-) T cells. CONCLUSION: These data indicate that regulatory CD4(+)CD25(+) T cells are present and functional in most atopic patients with allergic rhinitis and are able to inhibit T(H)1, as well as T(H)2, cytokine production.  相似文献   

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In normal mice a subpopulation of CD4 T cells constitutively expresses the IL-2 receptor alpha chain (CD25). This natural CD4 CD25(+) subset is thymus-born, constitutively expresses IL-10 mRNA,does not produce IL-2 and is resistant to apoptosis. These cells behave as regulatory T cells in the control of self-tolerance, inflammatory reactions and T cell homeostasis. The mechanisms by which natural CD4 CD25(+) cells control the immune response is unclear. We examined CD25-deficient mice, which over-express various cytokines, including proinflammatory molecules, after bacterial superantigen stimulation in vivo. We observed that this abnormal cytokine production could be controlled by the injection of natural CD4 CD25(+) T cells and that IL-10 production is needed, as CD4 CD25(+) T cells from IL-10 knockout mice do not correct cytokine over-production in vivo. As the circulating IL-10 produced by CD25-deficient mice was ineffective, we deduced that the key source of IL-10 was the regulatory T cell population. IL-10 is also involved in the control of cytokine production by normal T cells. However, the target of IL-10 in this control is undefined. Whether it acts directly on the effector T cells or on the regulatory CD4 CD25(+) T cells themselves to induce their functional maturation has to be clarified.  相似文献   

4.
The factors that influence the functionality of human CD4(+)CD25(+) regulatory T cells are not well understood. We sought to characterize the effects of dendritic cells (DCs) on the in vitro regulatory activity of CD4(+)CD25(+) T cells obtained from peripheral blood of healthy human donors. Flow cytometry showed that a higher proportion of CD4(+)CD25(+(High)) T cells expressed surface glucocorticoid-induced tumor necrosis factor receptor family-related protein (GITR) and CTL-associated antigen 4 than CD4(+)CD25(-) or CD4(+)CD25(+(Med-low)) T cells. Intracellular Foxp3 was equivalently expressed on CD4(+)CD25(+(All)), CD4(+)CD25(+(High)), CD4(+)CD25(+(Med-low)) and CD4(+)CD25(-) T cell populations, irrespective of GITR and CTL-associated antigen 4 expression. CD4(+)CD25(+) T cells were isolated and then cultured in vitro with CD4(+)CD25(-) responder T cells and stimulated with anti-CD3 antibodies, and immature dendritic cells (iDCs), mature dendritic cells (mDCs), PBMCs or PBMCs plus anti-CD28 antibodies to provide co-stimulation. In addition, secretion of the T(h)1 cytokine IFN-gamma, IL-2 and the immunoregulatory cytokines, IL-10 and transforming growth factor (TGF)-beta, were also assessed in these cultures. We found that iDCs and mDCs were capable of reversing the suppression of proliferation mediated by CD4(+)CD25(+) regulatory T cells. However, the reversal of suppression by DCs was not dependent upon the increase of IFN-gamma and IL-2 production or inhibition of IL-10 and/or TGF-beta production. Therefore, DCs are able to reverse the suppressive effect of regulatory T cells independent of cytokine production. These results suggest for the first time that human DCs possess unique abilities which allow them to influence the functions of regulatory T cells in order to provide fine-tuning in the regulation of T cell responses.  相似文献   

5.
Transforming growth factor beta (TGF-beta) has been shown to be a central immunomodulator used by leishmaniae to escape effective mechanisms of protection in human and murine infections with these parasites. However, all the information is derived from studies of established infection, while little is known about TGF-beta production in response to Leishmania stimulation in healthy subjects. In this study, TGF-beta1 production was demonstrated in peripheral blood mononuclear cells from healthy subjects never exposed to leishmaniae in response to live Leishmania guyanensis, and the TGF-beta1-producing cells were described as a distinct subpopulation of CD4(+) CD25(+) regulatory T cells. The suppressive properties of CD4(+) CD25(+) T cells were demonstrated in vitro by their inhibition of production of interleukin 2 (IL-2) and IL-10 by CD4(+) CD25(-) T cells in the presence of either anti-CD3 or L. guyanensis. Although neutralization of TGF-beta1 did not reverse the suppressive activity of CD4(+) CD25(+) T cells activated by anti-CD3, it reversed the suppressive activity of CD4(+) CD25(+) T cells activated by L. guyanensis. Altogether our data demonstrated that TGF-beta1 is involved in the suppressive activity of L. guyanensis-stimulated CD4(+) CD25(+) T cells from healthy controls.  相似文献   

6.
Naturally occurring CD4(+)CD25(+)FoxP3(+) regulatory T cells (CD25(+) Tregs) constitute a specialized population of T cells that is essential for the maintenance of peripheral self-tolerance. The immune regulatory function of CD25(+) Tregs depends upon their activation. We found that anti-CD4 antibodies activate the suppressive function of human CD25(+) Tregs in a dose-dependent manner. We demonstrate that CD4-activated CD25(+) Tregs suppress the proliferation of CD4(+) and CD8(+) T cells, their IL-2 and IFN-gamma production as well as the capacity of CD8(+) T cells to re-express CD25. By contrast, anti-CD4 stimulation did not induce suppressive activity in conventional CD4(+) T cells. These results identify CD4 as a trigger for the suppressive function of CD25(+) Tregs and suggest a possible CD4-mediated exploitation of these cells.  相似文献   

7.
人外周血CD4+CD25+调节性T细胞的分离、鉴定和功能特征   总被引:4,自引:7,他引:4  
目的: 分离人外周血CD4+ CD25+ Treg细胞, 并检测其功能.方法: RT-PCR技术检测CD4+ CD25+ Treg细胞中Foxp3的mRNA表达;与CD8+ T细胞和CD4+ CD25- T细胞共同培养, 或加入外源性IL-2及IL- 4, 检测其抑制功能;流式细胞术检测IFN-γ、 IL- 4和IL-10.结果: CD4+ CD25+ Treg细胞高表达Foxp3, 主要分泌IL-10, 能够抑制CD8+ T细胞和CD4+ CD25- T细胞的增殖, 高浓度IL-2能够阻断CD4+ CD25+ Treg细胞的抑制功能.结论: CD4+ CD25+ Treg细胞是一群具有免疫抑制功能的调节性T细胞, 这种抑制作用能够被高浓度IL-2阻断.  相似文献   

8.
The use of flow cytometry to detect intracellular cytokines at the single cell level has the potential to quantify cytokine production together with the possibility of phenotypic identification of the cell population concerned. The unbalanced presence of intracellular cytokines produced by T cells has been recognized in some pathological conditions. To better address this issue, we studied the production of IFN-gamma and IL-4 in CD4(+) and CD8(+high) T cells in healthy donors of a broad range of age (17-62 years). Given that an increase of IFN-gamma and IL-4 with aging had been reported by some authors in healthy controls, we have performed a multivariate analysis to assess the intrinsic role of aging or of other external factors, such as chronic antigenic exposures (i.e., viruses), over the cytokine production of phenotypically characterized T cells. In this respect we show that, mainly in CD8(+high) T cells, the production of IFN-gamma is directly correlated with age. Besides, the cytokine production correlates with the CD8(+high)CD28(-)CD57(+) T-cell population, which we have recently reported elevated in aged individuals. Perhaps this T-cell subpopulation plays a regulatory role as a Tc1 response in aging individuals.  相似文献   

9.
CD4+CD25+ T cells have been shown to play a regulatory or suppressive role in the immune response and are possibly relevant to the pathogenesis of autoimmune diseases. In the present study, we attempted to investigate the levels of CD4+CD25+ T cells in the peripheral blood (PB) and synovial fluid (SF) of patients with rheumatoid arthritis (RA) and the effects of CD4+CD25+ T cells on the in vitro cytokine production by stimulated SF mononuclear cells (SFMC). The results showed that RA patients had similar frequencies of CD4+CD25+ T cells in PB, expressed as a percentages of the lymphocyte population, as did healthy subjects (mean +/- SD: 10.52 +/- 5.87% versus 11.11 +/- 4.58%., respectively). But in contrast to PB, the SF of RA patients contained significantly higher levels of CD4+CD25+ T cells (17.77 +/- 7.92% versus 10.52 +/- 5.87%, respectively. P < 0.001). When cocultured in vitro with SFMC, CD4+CD25+ T cells purified from either PB or SF were found to exert a considerable suppressive effect on the production of cytokines including TNF-alpha, IFN-gamma and interleukin-10 (IL-10). The percentages of inhibition of each cytokines ranged from 41.8 to 98.4% (mean, 80.0%) for TNF-alpha, 42.8 to 98.9% (mean, 83.2%) for IFN-gamma and 59.3 to 96.6% (mean, 80.0%) for IL-10. Because both pro-inflammatory and anti-inflammatory cytokines were suppressed by CD4+CD25+ T cells, whether CD4+CD25+ T cells might play a beneficial role in the suppression of sustained inflammation in rheumatoid synovium remains to be elucidated.  相似文献   

10.
The current study was aimed at developing a one-way mixed leucocyte culture-enzyme-linked immunospot (MLC-ELISPOT) assay for the study of CD4(+) CD25(+) regulatory T (T(reg)) cells and applying this method in the study of antifetal immune reactions during human pregnancy. Twenty-one pregnant women and the corresponding fathers-to-be, and 10 non-pregnant control women and men, participated in the study. CD4(+) CD25(+) cells were isolated from peripheral blood mononuclear cells (PBMC) by immunomagnetic selection. Maternal/control PBMC were stimulated with paternal or unrelated PBMC in MLC. Secretion of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) from responder cells, with or without the presence of autologous T(reg) cells, was analysed by ELISPOT. PBMC from pregnant women showed increased secretion of IL-4 compared to controls. In pregnant and non-pregnant controls, T(reg) cells suppressed IFN-gamma reactivity against paternal and unrelated alloantigens. Interestingly, T(reg) cells suppressed IL-4 secretion against paternal but not unrelated alloantigens during pregnancy. We have successfully developed a model for studying T(reg) cells in antifetal cytokine reactions during pregnancy. Results indicate that T(reg) cells contribute to strict regulation of both T helper type 1-like and type 2-like antifetal immune reactions. Interestingly, T helper type 2-like cells specific to unrelated alloantigens are able to escape the suppression of T(reg) cells, which would allow for IL-4, alongside CD4(+) CD25(+) T(reg) cells, to control potentially detrimental IFN-gamma reactions during pregnancy.  相似文献   

11.
Th2 bias of CD4+ NKT cells derived from multiple sclerosis in remission   总被引:3,自引:0,他引:3  
Although CD1d-restricted NKT cells have been implicated as a participant in the regulatory mechanism of autoimmune diseases, it remains unclear how they would regulate human autoimmune diseases such as multiple sclerosis (MS). Furthermore, although the NKT cells comprise CD4(+) and CD4(-) populations, prior studies have often represented them as simply a CD4(-) population. Given that CD4(+) and CD4(-) NKT cells may represent functionally distinct populations, it appears crucial to examine the individual NKT subset in autoimmune diseases. Here we studied the frequency and cytokine phenotypes of the CD4(+) and CD4(-) NKT cells in fresh peripheral blood mononuclear cells, and of alpha-galactosylceramide-stimulated short-term cell lines obtained during the remission or relapse phase of MS as compared with from healthy subjects (HS). Here we report that CD4(+) NKT line cells expanded from MS in remission (MS-rem) would produce a larger amount of IL-4 than those from HS or from MS in relapse (MS-rel). They were significantly biased for T(h)2 as judged by the IL-4/IFN-gamma balance. However, there was no functional bias toward T(h)1 or T(h)2 in CD4(-) NKT line cells from MS-rem due to the defects in both IFN-gamma and IL-4 production, compared with HS. Of note, although double-negative NKT cells in the periphery were greatly reduced, the reduction of CD4(+) NKT cells was only marginal, if any, in MS-rem compared with HS. The T(h)2 bias of CD4(+) NKT line cells from MS-rem may support an immunoregulatory role for the CD4(+) NKT cells in vivo.  相似文献   

12.
13.
CD4(+) CD25(+) regulatory T cells are increasingly recognized as central players in the regulation of immune responses. In vitro studies have mostly employed allogeneic or polyclonal responses to monitor suppression. Little is known about the ability of CD4(+) CD25(+) regulatory T cells to suppress antigen-specific immune responses in humans. It has been previously shown that CD4(+) CD25(+) regulatory T cells anergize CD4(+) T cells and turn them into suppressor T cells. In the present study we demonstrate for the first time in humans that CD4(+) CD25(+) T cells are able to inhibit the proliferation and cytokine production of antigen specific CD4(+) and CD8(+) T cells. This suppression only occurs when CD4(+) CD25(+) T cells are preactivated. Furthermore, we could demonstrate that CD4(+) T-cell clones stop secreting interferon-gamma (IFN-gamma), start to produce interleukin-10 and transforming growth factor-beta after coculture with preactivated CD4(+) CD25(+) T cells and become suppressive themselves. Surprisingly preactivated CD4(+) CD25(+) T cells affect CD8(+) T cells differently, leading to reduced proliferation and reduced production of IFN-gamma. This effect is sustained and cannot be reverted by exogenous interleukin-2. Yet CD8(+) T cells, unlike CD4(+) T cells do not start to produce immunoregulatory cytokines and do not become suppressive after coculture with CD4(+) CD25(+) T cells.  相似文献   

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15.
Myasthenia gravis (MG) is caused by T-cell-dependent autoantibodies against muscle acetylcholine receptors (AChR) at the neuromuscular junction. Here, we adopted ELISA and flow cytometry techniques to measure the levels of Th1, Th2, Th3 cytokines, inflammatory cytokine and chemokine sICAM-1 and to analyze the phenotypes of CD4(+) and CD8(+) regulatory cells as well as the expression of BAFF-R on CD19(+) B cells in peripheral blood from 75 MG patients and 50 healthy controls. There were no differences in the levels of IL-2, IL-4, IL-10, IL-13, IFN-gamma, TNF-alpha, TGF-beta and sCTLA-4 in both sera and culture supernatants between MG patients and healthy controls. The level of IL-12 was decreased in culture supernatants from MG patients, and the level of sICAM-1 was increased in both sera and culture supernatants from MG patients. Although the populations of CD8(+)CD28(-) and CD8(+)CD122(+) regulatory T cells were not different between MG patients and healthy controls, MG patients exhibited the decrease of CD4(+)CD25(high)Foxp3(+) regulatory T cells and the increase of CD19(+)BAFF-R(+) B cells, revealing that MG patients should display the dysfunction of T cell balance and the activation of B cell maturation.  相似文献   

16.
Ageing is associated with evidence of immune deficiency and dysregulation. Key changes in the immune system with ageing include a progressive reduction in naive T cell output associated with thymic involution and peripheral expansion of oligoclonal memory T cells. These features are associated with evidence of impaired immune responsiveness both in vitro and in vivo, termed immune senescence. CD4+ CD25+ T cells have recently been recognized as mediators of peripheral immune regulation and play a role in the control of autoimmune and pathogen-specific immune responses. The significance of CD4+ CD25+ regulatory T cells in the context of immunosenescence is not known. We have investigated the number, phenotype and function of CD4+ CD25+ T cells in healthy volunteers over a wide age range. We demonstrate that the number of CD4+ CD25+ and CD4+ CD25high T cells in healthy volunteers increases with age. In both age groups CD4+ CD25+ T cells showed a phenotype consistent with that described for regulatory T cells. Further analysis of CD4+ CD25high T cells in young and elderly donors showed equivalent expression of intracellular CTLA-4 and surface expression of activation markers. In vitro, functional titration assays of CD4+ CD25high T cells demonstrated equivalent regulatory function in both young and elderly donors, with suppression of proliferation and cytokine production in response to polyclonal T cell stimulation. These observations demonstrate an increase in peripheral blood CD4+ CD25high regulatory T cells associated with ageing. The relevance of these expanded cells in relation to the immune senescence seen in the elderly as yet remains unclear.  相似文献   

17.
CD4+CD25+ T regulatory cells may play a role in the different clinical presentations of chronic hepatitis C virus (HCV) infection by suppressing CD4+ T cell responses. Peripheral CD4+CD25+ T cells from chronic HCV carriers with normal and abnormal alanine aminotransferase (ALT) were analysed for specificity and effect on HCV-specific CD4+ T cell reactivity by flow cytometry for intracellular cytokine production and proliferation assay. HCV-specific CD4+CD25(+high) T cells consistently produced transforming growth factor (TGF)-beta but only limited amounts of interleukin (IL)-10 and no IL-2 and interferon (IFN)-gamma. The HCV-specific TGF-beta response by CD4+CD25(+high) T cells was significantly greater in patients with normal ALT compared to patients with elevated ALT. In addition, a significant inverse correlation was found between the HCV-specific TGF-beta response by CD4+CD25(+high) T cells and liver inflammation. In peripheral blood mononuclear cells (PBMC), both HCV antigen-induced IFN-gamma production and proliferation of CD4+ T cells were greater in patients with elevated ALT compared with patients with normal ALT. Depletion of CD4+CD25+ cells from PBMC resulted in an increase of both IFN-gamma production and proliferation of HCV-specific CD4+ T cells that was significantly greater in patients with normal ALT levels compared with patients with elevated ALT. In addition, CD4+CD25+ T cells from patients with normal ALT levels proved to be significantly more potent to suppress CD4+ T cell reactivity with respect to those from patients with elevated ALT. In conclusion, these data support the hypothesis that CD4+CD25+ cells may play a role in controlling chronic inflammatory response and hepatic damage in chronic HCV carriers.  相似文献   

18.
Qiao M  Thornton AM  Shevach EM 《Immunology》2007,120(4):447-455
CD4(+) CD25(+) Foxp3(+) naturally occurring regulatory T cells (nTreg) are potent inhibitors of almost all immune responses. However, it is unclear how this minor population of cells is capable of exerting its powerful suppressor effects. To determine whether nTreg mediate part of their suppressor function by rendering naive T cells anergic or by converting them to the suppressor phenotype, we cocultured mouse nTreg with naive CD4(+) CD25(-) T cells from T-cell receptor (TCR) transgenic mice on a RAG deficient (RAG(-/-)) background in the presence of anti-CD3 and interleukin-4 (IL-4) to promote cell viability. Two distinct responder cell populations could be recovered from the cocultures. One population remained undivided in the coculture and was non-responsive to restimulation with anti-CD3 or exogenous IL-2, and could not up-regulate IL-2 mRNA or CD25 expression upon TCR restimulation. Those responder cells that had divided in the coculture were anergic to restimulation with anti-CD3 but responded to restimulation with IL-2. The undivided population was capable of suppressing the response of fresh CD4(+) CD25(-) T cells and CD8(+) T cells, while the divided population was only marginally suppressive. Although cell contact between the induced regulatory T cell (iTreg) and the responders was required for suppression to be observed, anti-transforming growth factor-beta partially abrogated their suppressive function. The iTreg did not express Foxp3. Therefore nTreg are not only able to suppress immune responses by inhibiting cytokine production by CD4(+) CD25(-) responder cells, but also appear to modulate the responder cells to render them both anergic and suppressive.  相似文献   

19.
Induction of IL-10+CD4+CD25+ T cells by grass pollen immunotherapy   总被引:24,自引:0,他引:24  
BACKGROUND: Immunotherapy involves the modulation of allergen-specific T-cell responses, either T(H)2-to-T(H)1 immune deviation or, in bee venom-treated patients, induction of IL-10 production by CD4+CD25+ T cells. IL-10-producing CD4+CD25+ regulatory T cells have emerged as potential mediators of immune tolerance in numerous murine models of immunopathology. OBJECTIVE: The aim of this study was to evaluate the role of IL-10 production and CD4+CD25+ T cells in the response to grass pollen immunotherapy. METHODS: PBMCs were isolated from patients after 1 year of grass pollen immunotherapy and from matched untreated atopic and healthy control subjects. After 6 days of in vitro stimulation with Phleum pratense, production of IL-10, IL-5, IL-4, and IFN-gamma and proliferation and numbers of CD4+CD25+ T cells were measured. T cells were then stimulated for a further 5 hours with phorbol 12-myristate 13-acetate and ionomycin and assessed for intracellular IL-10 by means of flow cytometry. RESULTS: Patients undergoing immunotherapy produced significantly more IL-10 than atopic control subjects (patients undergoing immunotherapy, 116 +/- 21 pg/mL [n = 11]; atopic patients, 30 +/- 5 pg/mL [n = 11]; P <.001), and the number of CD4+CD25+ cells identified after allergen stimulation was also greater in the immunotherapy group. The numbers of CD4+CD25+ T cells correlated positively with activation as measured by proliferation in both of the control groups but not in the immunotherapy group. Moreover, only T cells from patients undergoing immunotherapy were positive for intracellular IL-10, and these were almost exclusively CD4+CD25+ cells. CONCLUSION: Grass pollen immunotherapy results in a population of circulating T cells that express the IL-10(+) CD4+CD25+ phenotype in response to allergen restimulation.  相似文献   

20.
  目的 了解结核患者外周血中CD4+CD25+FoxP3+调节T细胞在抑制结核患者结核特异细胞免疫反应中的作用。 方法 使用细胞分离、流式细胞分析、细胞增殖和细胞因子测定等方法,比较结核患者及健康正常人群外周血中CD4+CD25+FoxP3+调节T细胞的量及功能特征的差异。 结果 结核患者外周血中CD4+CD25+FoxP3+调节T细胞数占CD4+细胞总数的比例显著高于健康正常人群;在BCG及ESAT-6的刺激下,结核患者外周血单个核细胞增殖能力和产生γ-干扰素的能力比健康正常人群明显增强。在BCG刺激下,结核患者外周血CD4-细胞产生γ-干扰素(1289.62±519.01)及白介素-10(1045.40±534.12)的能力比结核患者外周血BPMCs细胞产生γ-干扰素(624.50±261.13)及白介素-10(377.00±249.56)的能力显著增强(均p<0.05);在BCG及ESAT-6的刺激下,结核患者外周血CD4+CD25+调节T细胞显著抑制结核患者外周血CD4+CD25-细胞产生γ-干扰素及白介素-10。 结论 结核患者CD4+CD25+FoxP3+调节T细胞数量增多,抑制结核患者结核特异细胞免疫反应功能增强,可能与结核的发生、发展及转归有密切关系。  相似文献   

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