Activation of murine invariant NKT cells promotes susceptibility to candidiasis by IL‐10 induced modulation of phagocyte antifungal activity

Invariant NKT (iNKT) cells play an important role in a variety of antimicrobial immune responses due to their ability to produce high levels of immune‐modulating cytokines. Here, we investigated the role of iNKT cells in host defense against candidiasis using Jα18‐deficient mice (Jα18^?/?), which lack iNKT cells. Jα18^?/? mice were more resistant to the development of lethal candidiasis than wild‐type (WT) mice. In contrast, treatment of WT mice with the iNKT cell activating ligand α‐galactosylceramide markedly enhanced their mortality after infection with Candida albicans. Serum IL‐10 levels were significantly elevated in WT mice in response to infection with C. albicans. Futhermore, IL‐10 production increased after in vitro coculture of peritoneal macrophages with iNKT cells and C. albicans. The numbers of peritoneal macrophages, the production of IL‐1β and IL‐18, and caspase‐1 activity were also significantly elevated in Jα18^?/? mice after infection with C. albicans. The adoptive transfer of iNKT cells or exogenous administration of IL‐10 into Jα18^?/? reversed susceptibility to candidiasis to the level of WT mice. These results suggest that activation of iNKT cells increases the initial severity of C. albicans infection, most likely mediated by IL‐10 induced modulation of macrophage antifungal activity.     

IL-4/IL-10诱导的树突状细胞对类风湿性关节炎的作用

目的:探讨经IL-4/IL-10诱导的树突状细胞(DC)对类风湿性关节炎的作用。方法:用Percoll分层离心法从脾脏细胞分离得到DC后,用IL-4或IL-10或IL-4+IL-10进行诱导。用未经诱导和诱导过的DC对类风湿性关节炎大鼠模型进行干扰。SD鼠设为CIA模型组,DC对照组与DC试验组。用ELISA法检测细胞因子与抗体水平,用MTT法检测细胞增殖情况,对鼠爪关节行病理学检测。结果:DC对照组的临床症状评分,病理改变评分,细胞增殖能力,血清中抗胶原抗体及细胞因子水平与CIA模型组的差异无统计学意义。试验组中,注射IL-10-DC能改善CIA鼠的滑膜炎症情况;在初次免疫后第5天注射IL-4-DC能减轻CIA鼠的滑膜炎程度;注射IL-4+IL-10-DC无明显的保护作用。结论:适时注射IL-4或IL-10诱导的DC,对实验性类风湿性关节炎具有保护作用。     

IL-23 up-regulates IL-10 and induces IL-17 synthesis by polyclonally activated naive T cells in human

Interleukin (IL)-23 is a heterodimeric cytokine of the IL-12 family. Human IL-23 is known to induce interferon (IFN)-gamma production and proliferation in T cells, preferentially in the CD45RO+ memory subset. Yet, its role in the differentiation of human naive T cells remains largely unknown. We investigated the effect of recombinant human (rh)IL-23 on cord blood CD4+ and CD8+ T cells during polyclonal activation. The IL-23 receptor complex was not detectable in resting naive T cells. Nevertheless, both IL-23 receptor subunits, IL-12Rbeta1 and IL-23R, were rapidly induced after activation in both naive CD4+ and CD8+ T cells. In both cell types, rhIL-23 enhanced IFN-gamma production. This effect was demonstrable as early as 2 days after activation, illustrating that a functional IL-23 receptor is rapidly induced in naive T cells upon activation. In naive CD8+ T cells, rhIL-23 specifically induced the secretion of IL-17, a pro-inflammatory cytokine. Moreover, rhIL-23 significantly increased the production of IL-10 in both naive CD4+ and CD8+ T cells. IL-17 and IL-10 levels were not affected by the addition of rhIL-12. We conclude that IL-23 induces a specific cytokine profile, remarkably distinct from IL-12, in activated human naive T cells.     

CD4+ Foxp3+ regulatory T cells mediate Toxoplasma gondii-induced T-cell suppression through an IL-2-related mechanism but independently of IL-10

Acute Toxoplasma gondii infection comprises an immunosuppression stage, characterized by a reduction in T-cell proliferation in vitro. Treg cells maintain the homeostasis of the immune system, but their role in T. gondii-induced suppression has not been addressed. We show herein that immunosuppression, affecting both CD4(+) and CD8(+) T-cell proliferation, concurs with a reduction in Treg-cell number. The residual Treg cells, however, are activated and display an increased suppressive capacity. We show that selective elimination of Treg cells using Foxp3(EGFP) mice leads to a full recovery of CD4(+) and CD8(+) T-cell proliferation. After Treg-cell removal, a reduced production of IL-10 was observed, but IL-2 levels were unchanged. The numbers of IL-10-producing Treg cells also increased during infection, although the in vitro neutralization of this cytokine did not modify T-cell proliferation, suggesting that IL-10 does not mediate the Treg-mediated suppression. However, addition of rIL-2 in vitro fully restored T-cell proliferation from infected animals. Thus, we show that Treg cells mediate the T-cell suppression observed during acute T. gondii infection through an IL-2-dependent mechanism. Our results provide novel insights into the regulation of the immune response against T. gondii.     

T细胞与类风湿性关节炎

类风湿性关节炎(RA)是一种慢性、炎症性自身免疫性疾病,发病机制非常复杂,至今尚未阐明.尽管多种免疫细胞和分子被证实参与了RA的关节炎症反应和组织破坏,但抗原特异性T细胞的激活始终被认为是RA发病起始和进展的中心环节.不同亚群T细胞在RA发病中发挥不同作用,以往认为,自身抗原诱导的促炎性Th1细胞活化是RA发病的主要因...     

Interleukin-10 (IL-10) secretion in systemic lupus erythematosus and rheumatoid arthritis: IL-10-dependent CD4+CD45RO+ T cell-B cell antibody synthesis

Interleukin-10 (IL-10) is a major immunoregulatory cytokine and has a multitude of immunomodulatory effects in the immune system. In this study, we have examined the secretion andin vitro function of IL-10 in B cell hyperactivity in antibody production in two common autoimmune diseases, systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). IL-10 was detectable in serum of all active SLE and serum and synovial fluid samples of all RA patients but in none of the normal controls. B cells and CD4+CD45RO+ memory T cells secreted highly enhanced levels of IL-10 in SLE and RA versus normals. Increased IgM and IgG production by B cells-CD4+CD45RO+ T cells in SLE and RA was IL-10 dependent, since neutralization of IL-10 cytokine by anti-IL-10 antibody drastically reduced Ig synthesis in these coculture experiments. B cell hyperactivity in autoantibody production in SLE and RA may be a function of IL-10-dependent CD4+CD45RO+ Th2 cell activation. Therefore, IL-10 may play an important role in highly disturbed immune system and B cell-T cell function in these immune disorders.     

A natural protective function of invariant NKT cells in a mouse model of innate-cell-driven lung inflammation

Activation of invariant natural killer T (iNKT) cells by treatment with their α-galactosyl ceramide ligand provides therapeutic benefits in several immune inflammatory settings. Given the artificial nature of this stimulation, the natural regulatory functions of iNKT remain uncertain. Addressing this issue in a mouse model of innate-cell-driven lung inflammation induced by the cytokine/alarmin IL-33 that targets iNKT cells, we found that eosinophil and neutrophil recruitment was markedly increased in treated iNKT cell-deficient (Jα18 KO) mice, as was the local production of eotaxin and keratinocyte chemoattractant chemokines. By contrast, lung inflammation decreased after adoptive transfer of iNKT cells, which restored the WT inflammatory response in Jα18 KO mice. Finally, we established that this natural anti-inflammatory function of iNKT cells depends on their IFN-γ production and on endogenous IL-12. Our study provides the first evidence of a protective role of iNKT cells during lung inflammation that does not require pharmacological TCR engagement.     

Early activation of invariant natural killer T cells in a rheumatoid arthritis model and application to disease treatment

Invariant NKT (iNKT) cells are a distinctive subtype of CD1d‐restricted T cells involved in regulating autoimmunity and capable of producing various T helper type 1 (Th1), Th2 and Th17 cytokines. Activation of iNKT cells by their exogenous ligand α‐galactosylceramide (α‐GalCer) exerts therapeutic effects in autoimmune diseases such as rheumatoid arthritis (RA). However, the pathophysiological role of iNKT cells in RA, in the absence of exogenous stimulation, is incompletely understood. We investigated the potential pathophysiological effects of iNKT cells in mice with collagen‐induced arthritis (CIA), a model of RA. We found that iNKT cells underwent activation only in the early phases of the disease (6 days post‐induction). In the liver, but not the spleen or lymph nodes, this early activation led to the release of interleukins ‐4, ‐17A and ‐10 and of interferon‐γ; and an increased CD69 expression. Importantly, clinical and histological signs of arthritis were improved by the functional blockade of iNKT cells by a monoclonal antibody to CD1d at the early phase of the disease. This improvement was associated on day 6 post‐induction with decreased expression of co‐stimulatory molecules (CD80, CD86, CD40) on splenic dendritic cells and macrophages, whereas regulatory T‐cell suppressive effects and proportions were not modified. Taken in concert, these findings suggest that iNKT cells are activated early in the course of CIA and contribute to the pathogenesis of arthritis. Therefore, iNKT‐cell activation may be a valid treatment target in RA.     

Expression profiling of IL-10-regulated genes in human monocytes and peripheral blood mononuclear cells from psoriatic patients during IL-10 therapy

Interleukin-10 (IL-10), originally identified as an inhibitor of pro-inflammatory cytokine production, exerts multiple immunomodulatory functions. Its ability to inhibit a Th1 response has been used in clinical trials for the treatment of inflammatory diseases including psoriasis. However, little is known about the molecular mechanisms of IL-10 functions. We aimed at identifying possible mediators of in vitro IL-10 treatment in monocytes by gene chip technology using Hu95a Affymetrix mRNA arrays with 12,000 genes. To prove relevance of the identified genes for the clinical situation we compared these in vitro results with genes being regulated by IL-10 in peripheral blood mononuclear cells from psoriatic patients undergoing IL-10 therapy. A high proportion of the 1,600 genes up-regulated and 1,300 genes down-regulated in vitro was found to be similarly regulated in vivo. Some genes, which were previously unknown to be regulated by IL-10, can be assigned to known IL-10 functions like e.g. the increase of pathogen clearance. Other new potentially immunomodulating genes have been identified to be regulated by IL-10, but their impact needs to be experimentally evaluated. We could confirm a recently reported up-regulation of heme oxygenase-1 (HO-1). However, we demonstrate that the anti-inflammatory mechanisms of IL-10 remain functional even when HO-1 is irreversibly inhibited.     

Joint-derived T cells in rheumatoid arthritis react with self-immunoglobulin heavy chains or immunoglobulin-binding proteins that copurify with immunoglobulin

Rheumatoid arthritis patients were found to have CD4⁺ T cells that proliferate in response to autologous synovial fluid and plasma. T cell clones and polyclonal T cell lines were found to respond to antigen(s) eluted from protein A Sepharose and anti-human immunoglobulin (Ig) antibody Sepharose. The antigen(s) was further resolved to fractions that contained intact Ig or Ig heavy chain since the T cells responded to > 100 kDa and 40--60 kDa polypeptides derived from purified Ig under nonreducing and reducing conditions, respectively. These results indicated that the antigen(s) is either Ig heavy chain or Ig-binding proteins that copurify with Ig and Ig subunits. Pepsin and papain digestion of the antigenic fractions eluted from protein A destroyed the T cell reactivity. Since most Fab regions are resistant to these enzymes, further analyses are required to localize the antigenic epitope(s). The presence of Ig- or Ig-antigen complex-reactive T cells in arthritic joints implies that B cells expressing anti-Ig antibody (i.e. rheumatoid factor) may play an important role in antigen presentation to autoreactive T cells.     

类风湿性关节炎中外周T辅助细胞免疫特征分析

目的 探讨外周T辅助细胞(peripheral helper T cell,Tph)在类风湿性关节炎(rheumatoid arthritis,RA)患者中的免疫特征.方法 分离RA患者外周血(peripheral blood,PB)和关节积液(synovial fluid,SF)中的淋巴细胞,利用CXCR5和PD-1...     

Activation antigens on colonic T cells in inflammatory bowel disease: effects of IL-10

Activated T cells that express activation antigens are termed nonprofessional antigen‐presenting cells (T‐APCs). This study evaluates the ability of lamina propria lymphocytes (LPLs) in inflammatory bowel disease (IBD) to become T‐APCs. LPLs were stained by two‐colour immunofluorescence to determine the expression of activation antigens on T cells. Those from actively inflamed IBD mucosa expressed greater amounts of MHC class II (DR) and CD86 than did LPL T cells from disease controls or normal individuals. After culture in IL‐2 with or without IL‐10, the ability of the T‐APCs from IBD colon to stimulate allogeneic peripheral blood T cell proliferation was measured. The T‐APCs from IBD stimulated an allogeneic mixed lymphocyte reaction, particularly through their expression of DR and CD86, as demonstrated by antibody blocking. Normal LPLs acquired these properties only if repeatedly stimulated with allogeneic peripheral blood lymphocytes (PBLs) used as cell lines in the presence of IL‐2. Addition of IL‐10 reduced expression of activation antigens and the stimulatory ability of LPLs from either IBD patients or from these cell lines. In summary, LPLs from active IBD, but not from disease controls, express activation antigens that stimulate naïve T cells, a process that is reduced by IL‐10. This may contribute to perpetuation of the inflammation.     

Elevated circulating Th17 and follicular helper CD4+ T cells in patients with rheumatoid arthritis

It remains not fully elucidated the potential functions of Th17 cells and follicular helper T (Tfh) cells and secreting cytokines in the pathogenesis of rheumatoid arthritis (RA) and their association with disease activity. In this study, the frequencies of Th17 and Tfh cells were determined by flow cytometry, and the levels of interleukin (IL)‐17, IL‐21, and IL‐22 were measured by ELISA in RA patients with different disease activities. The dynamic changes of cell subsets were also detected in response to disease‐modify antirheumatic drugs (DMARDs) therapy. The percentages of CD3⁺CD4⁺IL‐17A⁺ (Th17) cells and CD3⁺CD4⁺CXCR5⁺ICOS^high (Tfh) cells, as well as the concentrations of IL‐17, IL‐21, and IL‐22 were significantly elevated in RA patients than those in healthy individuals. Furthermore, Tfh cells, IL‐21, and IL‐22 in the serum was positively correlated with the values of disease activity score. Concentrations of IL‐21 and IL‐22 in the serum were remarkably reduced following the DMARDs therapies. Our data suggested that Th17 cells, Tfh cells as well as the secreting cytokines may be involved in the pathogenesis of RA. The frequency of circulating Tfh cells and the productions of IL‐21 and IL‐22 were associated with the disease activity of RA patients, and might be potential therapeutic targets for treatment of RA.     

类风湿关节炎患者外周血Tfh及Th9的变化及临床意义

目的 观察类风湿关节炎(RA)患者外周血中滤泡辅助性T细胞(Tfh)及T辅助细胞9(Th9)的变化,并与病情活动性及脏器受累等临床资料进行相关性分析,探讨Tfh及Th9在RA发病过程中可能的免疫学发病机制.方法 选择36例RA患者和22例健康对照.根据病情活动度不同将病例组分为病情高度活动组(22例)、病情中度活动组(14例),流式细胞仪检测RA和正常对照组外周血单个核细胞( PBMCs)中CD4-FITC、CXCR5-PE、ICOS-APC标记的CD4+ CXCR5+ ICOS+(Tfh)及CD8-FITC、CD3-APC、IL9-PE标记的CD3+CD8-IL-9+( Th9)比例.分析Tfh及Th9与RA患者的血沉(ESR)、C反应蛋白(CRP)、类风湿因子(RF)、关节压痛数、肿胀数及骨质破坏等指标的相关性;分析Tfh与Th9的关系.结果 RA患者的Tfh表达率明显高于对照组(Z=-6.082,P=0.000),RA患者Th9的表达率亦高于对照组(0.989±0.498 vs 0.213 ±0.084,t=13.063,P=0.000);RA重度活动组Tfh表达率亦高于中度活动患者的表达率(3.880±1.255 vs 2.678±1.022,t=2.990,P=0.005),且两组Tfh的表达率均高于对照组(P均＜0.01);RA重度活动患者Th9表达率高于中度患者(1.181±0.523 vs 0.686±0.254,t=4.043,P=0.000),且两组Th9的表达率亦均高于对照组(P均＜0.01); Tfh 细胞数与RA患者DAS28(r=0.571,P=0.000)、ESR(r=0.375,P=0.029)、CRP(r=0.357,P=0.032)、关节压痛数(r=0.598,P=0.000)、RF(r=0.421,P=0.023)及抗CCP滴度(r=0.421,P=0.023)正相关;与病程、晨僵、关节肿胀数、骨质破坏、心电图异常无相关性.Th9表达的百分率与RA患者的DAS28( r=0.461,P=0.005)、ESR(r=0.347,P=0.042)、CRP(r=0.384,P=0210)、关节压痛数(r=0.341,P=0.042)、关节肿胀数(r=0.347,P=0.038)及RF(r=0.379,P=0.025)正相关,与病程、晨僵时间、抗CCP滴度、心电图异常及骨质破坏无相关性;Tfh与Th9在外周血中的表达率呈正相关(r=0.727,P=0.000).结论 RA患者外周血Tfh及Th9的比例显著升高,且与疾病活动度及相关炎症指标明显相关,提示Tfn及Th9可能参与RA的发病及病情发展.     

IL-10-dependent partial refractoriness to Toll-like receptor stimulation modulates gut mucosal dendritic cell function

The default response of the intestinal immune system to most antigens is the induction of immunological tolerance, which is difficult to reconcile with the constant exposure to ligands for TLR and other pattern recognition receptors. We showed previously that dendritic cells (DC) from the lamina propria of normal mouse intestine may be inherently tolerogenic and here we have explored how this might relate to the expression and function of Toll-like receptors (TLR). Lamina propria (LP) DC showed higher levels of TLR 2, 3, 4 and 9 protein expression than spleen and MLN DC, with most TLR-expressing DC in the gut being CD11c(lo), class II MHC(lo), CD103(-), CD11b(-) and F4/80(-). TLR expression by lamina propria DC was low in the upper small intestine and higher in distal small intestine and colon. Freshly isolated lamina propria DC expressed some CD40, CD80, CD86 and functional CCR7. These were up-regulated on CD11c(lo), but not on CD11c(hi) LP DC by stimulation via TLR. However, there was little induction of IL-12 by either subset in response to TLR ligation. This was associated with constitutive IL-10 production and was reversed by blocking IL-10 function. Thus, IL-10 may maintain LP DC in a partially unresponsive state to TLR ligation, allowing them to have a critical role in immune homeostasis in the gut.     

Small interference RNA modulation of IL-10 in human monocyte-derived dendritic cells enhances the Th1 response

RNA interference technology has been used to modulate dendritic cell (DC) function by targeting the expression of genes such as IL-12 and NF-kappa B. In this paper, we demonstrate that transfection of DC with IL-10-specific double strands of small interference RNA (siRNA) resulted in potent suppression of IL-10 gene expression without inducing DC apoptosis or blocking DC maturation. Inhibition of IL-10 by siRNA was accompanied by increased CD40 expression and IL-12 production after maturation, which endowed DC with the ability to significantly enhance allogeneic T cell proliferation. IL-10 siRNA transfection did not affect MHC class II, CD86, CD83, or CD54 expression in mature DC. To further test the ability of IL-10 siRNA-treated DC to induce a T cell response, naive CD4 T cells were stimulated by autologous DC pulsed with KLH. The results indicated that IL-10 siRNA-transfected DC enhanced Th1 responses by increasing IFN-gamma and decreasing IL-4 production. These findings suggest the potential for a novel immunotherapeutic strategy of using IL-10 siRNA-transfected antigen-presenting cells as vaccine delivery agents to boost the Th1 response against pathogens and tumors that are controlled by Th1 immunity.     

Expression, modulation and signalling of IL-17 receptor in fibroblast-like synoviocytes of patients with rheumatoid arthritis

Interleukin-17 (IL-17) has been characterized as a proinflammatory cytokine produced by CD4+ CD45RO+ memory T cells. Overproduction of IL-17 was detected in the synovium of patients with rheumatoid arthritis (RA) compared to patients with osteoarthritis. In contrast to the restricted expression of IL-17, the IL-17 receptor (IL-17R/CDw217) is expressed ubiquitously. Using a real-time RT-PCR assay, we detected similar absolute levels of IL-17R mRNA expression in fibroblast-like synoviocytes (SFC) from patients with RA (mean 9 pg/microg total RNA; ranged from 0.1 pg to 96 pg IL-17R mRNA/microg total RNA) compared to synoviocytes of non-RA patients. Analysis of the IL-17R surface expression confirmed the results obtained for IL-17R mRNA expression. Exposure of SFC to IL-17 led to a mRNA induction of CXC chemokines IL-8, GRO-alpha and GRO-beta. An anti-IL-17 antibody blocked these effects of IL-17. The MAPK p38 appears necessary for the regulation of IL-8, GRO-alpha and GRO-beta expression as shown by inhibition with SB203580. The inhibitors genistein (tyrosine kinase inhibitor) and calphostin C (inhibitor of protein kinase C) reduced significantly the IL-17-stimulated mRNA expression of IL-8, GRO-alpha and GRO-beta in SFC, whereas PD98059 (inhibitor of MEK-1/2) was without effect. Pharmacological drugs used in therapy of RA, such as cyclosporin and methotrexate, induced a fourfold increase of IL-17R mRNA expression and augmented the IL-17-stimulated IL-8 expression. Our results support the hypothesis that IL-17/IL-17R may play a significant role in the pathogenesis of RA contributing to an unbalanced production of cytokines as well as participating in connective tissue remodelling.     

Regulation of T cells and cytokines by the interleukin-10 (IL-10)-family cytokines IL-19, IL-20, IL-22, IL-24 and IL-26

The family of IL-10-related cytokines includes several human members, IL-19, IL-20, IL-22, IL-24 and IL-26, and a series of herpesviral and poxviral paralogs. Some of these cytokines share common receptor subunits. In this study, we investigated the effects of these cytokines on naive T cell differentiation, antigen-specific T cell suppression, survival ad expression of surface markers in comparison to IL-10 and cytomegalovirus (CMV)-IL-10. Human CD45RA(+) T cells were stimulated in the presence of IL-10-family cytokines in sequential 12-day cycles. After three to four cycles of stimulation, IL-10 and CMV-IL-10 led to increased IFN-gamma and IL-10 but decreased IL-4 and IL-13. Interestingly, long-term exposure of T cells to IL-19, IL-20 and IL-22 down-regulated IFN-gamma but up-regulated IL-4 and IL-13 in T cells and supported the polarization of naive T cells to Th2-like cells. In contrast, neutralization of endogenous IL-22 activity by IL-22-binding protein decreased IL-4, IL-13 and IFN-gamma synthesis. The antigen-specific suppressor activity of IL-10 and CMV-IL-10 was not observed for any of the other IL-10-family cytokines. These data demonstrate that IL-19, IL-20 and IL-22 may participate in T cell-mediated diseases by distinct regulation of T cell cytokine profiles.