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-37抑制脂多糖诱导的小鼠树突状细胞活化

目的探讨白细胞介素37(IL-37)对细菌脂多糖(LPS)诱导的小鼠树突状细胞(DC)活化的调节作用。方法应用GM-CSF和IL-4诱导小鼠骨髓细胞向DC分化,抗CD11c磁珠分选DC。IL-37预处理DC后,进行LPS刺激。流式细胞术检测DC表面共刺激分子(CD80、CD86)表达水平,实时荧光定量PCR检测肿瘤坏死因子α(TNF-α)、IL-6和IL-1αmRNA表达水平,流式细胞微球芯片试剂盒(CBA试剂盒)检测细胞培养上清中IL-1α、IL-6、TNF-α等因子的浓度。结果 DC诱导成功,磁珠分选能够获得高纯度的DC(>90%)。IL-37降低LPS诱导的DC表面共刺激分子CD80、CD86的表达,并抑制DC合成IL-1α、IL-6、TNF-α。结论 IL-37可以通过降低共刺激分子和炎症因子的表达抑制LPS刺激的DC活化。     

IL-4 down-regulates the surface expression of CD5 on B cells and inhibits spontaneous immunoglobulin and IgM-rheumatoid factor production in patients with rheumatoid arthritis.

There is evidence to suggest that CD5+ B cells may be associated with autoimmunity, e.g. they are increased in patients with rheumatoid arthritis (RA). In this study, we found that the expression of CD5 on RA B cells increased spontaneously, following culture for up to 4 days in vitro in the absence of T cells, supporting the idea that the CD5+ B cell possesses distinctive features. The spontaneous increase of CD5 expression was down-regulated by recombinant IL-4 (rIL-4). Other cytokines studied (rIL-1 alpha, rIL-2, rIL-5, rIL-6) did not alter CD5 expression. Studies of antibody production showed that rIL-4 could reduce spontaneous production of total IgG and IgM in non-stimulated RA T plus B cell cultures. Spontaneous production of IgM rheumatoid factor (IgM-RF), measured by a newly developed avidin-biotin complex ELISA, was also reduced by rIL-4. Furthermore, rIL-4 reduced the increase in IgM-RF production observed on stimulation with Staphylococcus aureus Cowan I (SAC) or pokeweed mitogen (PWM). Thus, IL-4 might act as a regulator of the development of abnormal B cell differentiation in patients with RA.     

IL-18 produced by thymic epithelial cells induces development of dendritic cells with CD11b in the fetal thymus

Thymic dendritic cells (DCs) are suggested to be involved in T cell selection; however, their exact origin and function remain to be established. Although DCs in the adult thymus are mostly CD8alpha(+)CD11b(-), we found that CD8alpha(-)CD11b(+) DCs were abundantly present in the fetal thymus and they possessed antigen-presenting activity. Interestingly, these CD11b(+) DCs were significantly decreased in mice deficient for TNFR-associated factor 6 (TRAF6), a key signaling molecule downstream of IL-1 and tumor necrosis factor-alpha that have been known to induce DCs from intra-thymic precursor cells. CD11b(+) DCs were induced from CD4(-)CD8(-) thymocytes by fetal thymic epithelial cells (TECs). Analysis of cytokine expression in TECs revealed that none of the cytokines previously shown to induce DCs were expressed. Instead, we found strong expression of IL-18 that transmits signals through TRAF6. IL-18 induced CD11b(+) DCs from CD4(-)CD8(-) thymocytes in vitro, which exhibited strong antigen-presenting activity and formed conjugates with CD4(+)CD8(+) T cells efficiently. Taken together, these results strongly suggest that CD11b(+) DCs are differentiated from CD4(-)CD8(-) thymocytes by IL-18 produced from TECs and that they are involved in T cell selection in the fetal thymus.     

Tetraspanin CD37 contributes to the initiation of cellular immunity by promoting dendritic cell migration

Previous studies on the role of the tetraspanin CD37 in cellular immunity appear contradictory. In vitro approaches indicate a negative regulatory role, whereas in vivo studies suggest that CD37 is necessary for optimal cellular responses. To resolve this discrepancy, we studied the adaptive cellular immune responses of CD37^?/? mice to intradermal challenge with either tumors or model antigens and found that CD37 is essential for optimal cell‐mediated immunity. We provide evidence that an increased susceptibility to tumors observed in CD37^?/? mice coincides with a striking failure to induce antigen‐specific IFN‐γ‐secreting T cells. We also show that CD37 ablation impairs several aspects of DC function including: in vivo migration from skin to draining lymph nodes; chemo‐tactic migration; integrin‐mediated adhesion under flow; the ability to spread and form actin protrusions and in vivo priming of adoptively transferred naïve T cells. In addition, multiphoton microscopy‐based assessment of dermal DC migration demonstrated a reduced rate of migration and increased randomness of DC migration in CD37^?/? mice. Together, these studies are consistent with a model in which the cellular defect that underlies poor cellular immune induction in CD37^?/? mice is impaired DC migration.     

树突状细胞对佐剂性关节炎作用的实验研究

本文建立了大鼠佐剂性关节炎模型，经体内应用ＷＺＤ５（大鼠树突状细胞单抗）和输注新鲜分离的同系大鼠淋巴树突状细胞，以模型鼠的关节肿胀率和关节组织的病理改变、ＣｏｎＡ刺激淋巴细胞增殖反应和循环免疫复合物等为指标，来分析树突状细胞在佐剂性关节炎发病过程中的作用。结果表明：该细胞具有促进佐剂性关节炎的作用，而ＷＺＤ５则能减少关节肿胀率、减轻病变、缩短病程。     

CD147 modulates the differentiation of T‐helper 17 cells in patients with rheumatoid arthritis

The role of CD147 in regulation of rheumatoid arthritis (RA) is not fully elucidated. The aim of this study was to investigate the effect of cell‐to‐cell contact of activated CD14⁺ monocytes with CD4⁺ T cells, and the modulatory role of CD147 on T‐helper 17 (Th17) cells differentiation in patients with RA. Twenty confirmed active RA patients and twenty normal controls were enrolled. CD4⁺ T cells and CD14⁺ monocytes were purified by magnetic beads cell sorting. Cells were cultured under different conditions in CD4⁺ T cells alone, direct cell‐to‐cell contact co‐culture of CD4⁺ and CD14⁺ cells, or indirect transwell co‐culture of CD4⁺/CD14⁺ cells in response to LPS and anti‐CD3 stimulation with or without anti‐CD147 antibody pretreatments. The proportion of IL‐17‐producing CD4⁺ T cells (defined as Th17 cells) was determined by flow cytometry. The levels of interleukin (IL)‐17, IL‐6, and IL‐1β in the supernatants of cultured cells were measured by ELISA. The optimal condition for in vitro induction of Th17 cells differentiation was co‐stimulation with 0.1 μg/mL of LPS and 100 ng/mL of anti‐CD3 for 3 days under direct cell‐to‐cell contact co‐culture of CD4⁺ and CD14⁺ cells. Anti‐CD147 antibody reduced the proportion of Th17 cells, and also inhibited the productions of IL‐17, IL‐6, and IL‐1β in PBMC culture from RA patients. The current results revealed that Th17 differentiation required cell‐to‐cell contact with activated monocytes. CD147 promoted the differentiation of Th17 cells by regulation of cytokine production, which provided the evidence for pathogenesis and potential therapeutic targets for RA.     

Susceptibility of aging mice to listeriosis: Role of anti-inflammatory responses with enhanced Treg-cell expression of CD39/CD73 and Th-17 cells

Foodborne Listeria monocytogenes (Lm) causes serious illness and death in immunosuppressed hosts, including the elderly population. We investigated Lm susceptibility and inflammatory cytokines in geriatric mice. Young-adult and old mice were gavaged with a Lm strain Lmo-InlA^m. Tissues were assayed for Lm burden and splenocytes were analyzed for Th1/Th2/Th17/Treg responses and expression of CD39 and CD73. Old Lm-infected mice lost body-weight dose-dependently, had higher Lm colonization, and showed higher inflammatory responses than Lm-infected young-adult mice. After infection, IL-17 levels increased significantly in old mice whereas IFN-γ levels were unchanged. Levels of IL-10 and Treg cells were increased in infected old mice as compared to infected young-adult mice. Age-dependent enhanced expression of CD39/CD73 was observed in purified Treg prior to infection, suggesting increased baseline adenosine production in old mice. Lm lysate-treated splenocytes from older mice produced significantly higher levels of IL-10, IL17, and IL-1β, produced less IFN-γ and IL-2, and proliferated less than splenocytes from young-adult mice. Data suggests that older mice maybe more susceptible to Lm infection due to an imbalance of Th cell responses with disproportionate and persistent anti-inflammatory responses. Lm infection enhanced differentiation of proinflammatory Th17 cells, which may also exacerbate pathological responses during listeriosis.     

IL-6 inhibits the proliferation of fibroblastic synovial cells from rheumatoid arthritis patients in the presence of soluble IL-6 receptor

IL-6 and tumor necrosis factor (TNF)-alpha have been proven to play an important role in the development of rheumatoid arthritis (RA). It is well known that TNF-alpha induces IL-6 production from synovial cells as well as their proliferation. The effect of IL-6 on synovial cells, however, is not clear. An in vitrostudy was performed to determine the effect of IL-6 on the proliferation of synovial cells. Fibroblastic synovial cells isolated from the synovial tissues of eight RA patients were employed after the third to sixth passages. IL-6 in the presence of soluble IL-6 receptor (sIL-6R) inhibited the proliferation of synovial cells in a dose-dependent manner in seven cases without increasing the number of necrotic or apoptotic cells, while TNF-alpha increased synovial cell proliferation in all cases. The inhibitory effect of IL-6 was observed only in the presence of sIL-6R although small amounts of IL-6R were detected in these cells by RT-PCR analysis. However, anti-IL-6R or anti-gp130 mAb treatment increased spontaneous growth of synovial cells in all eight cases, suggesting that endogenous IL-6 and a small amount of IL-6R expressed in synovial cells suppressed their growth without exogenous IL-6 or sIL-6R. In addition, the IL-6-sIL-6R complex reduced the TNF-alpha-induced proliferation of synovial cells while TNF-alpha induced their IL-6 production. These data suggest that IL-6 may act as a negative feedback factor for TNF-alpha-induced synovial cell growth.     

Critical role of CCL22/CCR4 axis in the maintenance of immune homeostasis during apoptotic cell clearance by splenic CD8α+ CD103+ dendritic cells

Macrophages and dendritic cells (DCs) in murine spleen are essential for the maintenance of immune homeostasis by elimination of blood‐borne foreign particles and organisms. It has been reported that splenic DCs, especially CD8α⁺ CD103⁺ DCs, are responsible for tolerance to apoptosis‐associated antigens. However, the molecular mechanism by which these DCs maintain immune homeostasis by blood‐borne apoptotic cell clearance remains elusive. Here, we found that the CCL22/CCR4 axis played a critical role in the maintenance of immune homeostasis during apoptotic cell clearance by splenic CD8α⁺ CD103⁺ DCs. The present results revealed that systemic administration of apoptotic cells rapidly induced a large number of CCL22 and CCR4⁺ regulatory T (Treg) cells in the spleen of C57BL/6J mice. Further study demonstrated that CD8α⁺ CD103⁺ DCs dominantly produce much higher CCL22 than CD8α⁺ CD103^? DCs. Moreover, the transient deletion of CD8α⁺ CD103⁺ DCs caused a decrease in CCL22 levels together with CCR4⁺ Treg cell percentage. Subsequently, the levels of some pro‐inflammatory cytokines, such as interleukin‐17 and interferon‐γ in the spleen with the absence of CD8α⁺ CD103⁺ DCs increased in response to the administration of apoptotic cells. Hence, intravenous injection of apoptotic cells induced a subsequent increase in CCL22 expression and CCR4⁺ Treg cells, which contribute to the maintenance of immune homeostasis at least partially by splenic CD8α⁺ CD103⁺ DCs.     

A high proportion of the V delta 1+ synovial fluid gamma delta T cells in juvenile rheumatoid arthritis patients express the very early activation marker CD69, but carry the high molecular weight isoform of the leucocyte common antigen (CD45RA).

We have previously shown that gamma delta T cells in the synovial compartment of patients with juvenile rheumatoid arthritis (JRA) express activation antigens (CD69 and HLA-DR) and that they are predominantly of the V delta 1 subset. In this study we have analysed the expression of activation antigens (CD69 and HLA-DR) and different isoforms of the leucocyte common antigen (CD45RO and CD45RA) on the V delta 1 and the V delta 2 subsets of gamma delta T cells in paired samples of synovial fluid and peripheral blood of nine patients with JRA, and in the peripheral blood of five children with idiopathic scoliosis. In the synovial fluid of children with JRA, there were significantly more V delta 1+CD69+ and V delta 2+CD69+ cells compared with the peripheral blood of the same patients. In contrast, however, in the synovial fluid the V delta 1 and the V delta 2 subsets differed with respect to the expression of the two isoforms of the leucocyte common antigen. The majority of the V delta 1+ cells expressed the high molecular weight isoform (CD45RA+) while most of the V delta 2+ cells carried the low molecular weight variant (CD45RO+) of this molecule.