Human placental trophoblasts express the immunosuppressive cytokine IL-35

Studies of maternal–fetal tolerance focus on defining mechanisms for establishment of immunological privilege within the uterus during pregnancy. Fetal trophoblasts play a key role in maternal tolerance, in part through cytokines production. As a novel inhibitory cytokine, IL-35 is produced by Foxp3⁺ regulatory T cells (Tregs) and mediates maximal suppression of Tregs. The purpose of the study is to analyze the expression of IL-35 in first-trimester human placental trophoblasts. IL-35 expression was detected at both protein and mRNA levels by immunohistochemical staining and quantitative real-time PCR method, respectively and secretion of IL-35 was measured by ELISA assay. Our results demonstrated that human trophoblasts constitutively expressed IL-35. Ebi3 and p35 (two subunits of IL-35) mRNA was shown to be co-expressed in trophoblast cells. Moreover, large amounts of secreted IL-35 were detected in the supernatants of trophoblast cells. But we did not detect the constitutive expression of IL-35 in decidual stromal cells. Our findings confirmed for the first time that first-trimester human trophoblast cells expressed and secreted IL-35, which might contribute to their suppressive capacity to maternal immune cells. Therefore, IL-35 may be an important factor of the cytokine network regulating local immune responses during human pregnancy.     

IL-10 expression profiling in human monocytes

Interleukin-10 (IL-10) is a potent anti-inflammatory cytokine with numerous immunomodulatory effects, including the inhibition of proinflammatory cytokine production. The mechanisms by which IL-10 exerts these effects still remain largely unknown. As there is evidence that suggests IL-10-mediated cytokine suppression requires the induction of an intermediate gene, we have used gene-chip technology to identify IL-10-inducible genes in human monocytes. We have been able to identify a total of 19 genes that are up-regulated in response to IL-10. Three of these genes had been identified previously: IL-1ra, suppressors of cytokine signaling-3, and CD163; however, the other 16 represent newly identified IL-10-responsive genes. Further analysis of the regulation of eight of these genes showed a remarkable specificity to regulation by lipopolysaccharides (LPS) and IL-10, but not by other anti-inflammatory mediators such as IL-4 and transforming growth factor-beta, suggesting that two diverse stimuli such as IL-10 and LPS may engage common signaling mechanisms.     

白细胞介素6(IL-6)和IL-8mRNA在变应原诱导的鼻粘膜晚期反应标本的表达

目的测定IL-6和IL-8变应原诱导的鼻粘膜晚期反应标本中mRNA的表达。方法采用原位杂交技术,测定变应原诱导的10例变态反应性鼻炎病人的鼻粘膜标本表达IL-6和IL-8mRNA阳性细胞数。结果在10例标本中,2种细胞因子的阳性表达率分别为9/10和10/10。与对照相比,变应原诱导的鼻粘膜标本表达IL-6和IL-8mRNA阳性细胞数明显增加(P＜0.05和P＜0.01)。结论IL-6和IL-8mRNA表达增加可作为变态反应性鼻炎晚期的标志。     

Paradoxical priming effects of IL-10 on cytokine production.

IL-10 is a well-known immunosuppressive and/or anti-inflammatory cytokine. However, we report in vitro experimental studies in which IL-10 primed leukocytes and led to an enhanced production of tumor necrosis factor (TNF) upon further stimulation by lipopolysaccharide (LPS). Monocytes and peripheral blood mononuclear cells (PBMC) prepared from whole blood maintained for 20 h at 37 degrees C in the presence of recombinant human IL-10 had an enhanced capacity to produce TNF in response to LPS. In addition to TNF, LPS-induced IL-6 and spontaneous IL-1ra production were also enhanced. When isolated PBMC were first cultured for 20 h in the presence of IL-10 on Teflon to prevent adherence, washed to remove IL-10 and then further cultured in plastic dishes for an additional 20 h in the presence of LPS or IL-1beta, an enhanced release of TNF was observed. This was not the case when PBMC were pre-cultured in plastic multidishes in the presence of IL-10. TNF mRNA expression induced by LPS was decreased when the pre-treatment of PBMC with IL-10 was performed on plastic, whereas this was not the case when cells were pre-cultured with IL-10 on Teflon. Furthermore, NFkappaB translocation following LPS activation was higher after IL-10 pre-treatment on Teflon than on plastic. Interestingly, an enhanced frequency of CD16 and CD68(+) cells among the CD14(+) cells was observed in the presence of IL-10, independently of the pre-culture conditions of the PBMC. Altogether, these results indicate that the IL-10-induced up-regulation of cytokine production depends on the prevention of monocyte adherence by red cells in the whole blood assays or by cultures of PBMC on Teflon. In contrast, the adherence parameter has no effect on the IL-10-induced modulation of some monocyte surface markers.     

Impact of IL-10 on diaphragmatic cytokine expression and contractility during Pseudomonas Infection

Severe weakness of the respiratory muscles, with attendant respiratory failure and death, has been documented in sepsis. In this study, we show that during murine pulmonary infection with Pseudomonas aeruginosa, multiple proinflammatory genes are up-regulated not only within the lungs, but also within the diaphragm. Significant induction of TNF-alpha, IL-1alpha, IL-1beta, IL-6, and IL-18 gene expression occurred within the diaphragm in a bacterial dose-dependent manner. We determined whether the anti-inflammatory cytokine IL-10 could blunt proinflammatory gene expression within the diaphragm under these conditions. The IL-10 receptor was found to be expressed by the diaphragm in vivo as well as in primary diaphragmatic muscle cell cultures. Transduction of myoblasts with an adenoviral vector (Ad-IL-10) induced strong IL-10 expression, and intramuscular injection of the same vector in vivo produced significant increases in IL-10 serum levels. Ad-IL-10 treatment of mice infected with P. aeruginosa significantly inhibited the induction of proinflammatory cytokines within the diaphragm, but not in the infected lungs. Ad-IL-10 treatment also led to greatly improved diaphragmatic force production in infected mice. These results suggest that pulmonary infection triggers proinflammatory gene expression by the diaphragm along with diaphragmatic weakness. Shifting the balance between pro- and anti-inflammatory mediators in favor of the latter by IL-10 gene delivery was able to restore normal diaphragmatic force-generating capacity under these conditions, suggesting a possible avenue for therapeutic intervention.     

Functional characterization of human IL-10.

Rapid progress has been made over the past two years in the characterization of the biological activities of interleukin-10. Interleukin-10, produced by T cells, B cells, macrophages/monocytes and keratinocytes, alters profoundly the morphology, the expression of MHC class II antigens and the production of cytokines by monocytes which in turn can affect a variety of immunological responses including antigen specific proliferation and cytokine production of both soluble and allo-antigens by T cells, cytokine production by natural killer cells and immunoglobulin production by B cells. IL-10 also directly affects the function and growth of T cells, B cells and mast cells. These characteristics indicate that IL-10 has strong anti-inflammatory activities and may act as a general suppressor factor of immune reactions with consequences for transplantation, tolerance, cancer therapy and infectious diseases.     

Loss of heterozygosity for 10q loci in human gliomas.

Cytogenetic and RFLP studies have shown that chromosome 10 is frequently lost in tumor cells from glioblastomas, suggesting that a suppressor gene important in tumorigenesis is present on this chromosome. Forty-one tumors were examined for loss of heterozygosity at 23 loci on chromosome 10 to determine the smallest common deletion interval on this chromosome. Seven tumors did not lose heterozygosity for any of the markers. Twenty-three tumors lost an allele for all the informative loci. In 11 tumors heterozygosity was maintained at some loci and lost at other loci, indicating partial deletion of chromosome 10. The common region of deletion in these 11 tumors was located in 10q24-q26 between the markers pHUK-8 and pMCT122.2.     

ER stress abrogates the immunosuppressive effect of IL-10 on human macrophages through inhibition of STAT3 activation

Inflammation Research - To determine whether ER stress affects the inhibitory pathways of the human immune system, particularly the immunosuppressive effect of IL-10 on macrophages. In vitro...     

Endogenous IL-10 regulates IFN-gamma and IL-5 cytokine production and the granulomatous response in Schistosomiasis mansoni-infected mice.

In murine Schistosomiasis mansoni circumovum, granuloma formation is regulated by pro- and anti-inflammatory cytokines. Among the latter, interleukin-10 (IL-10) has been shown to regulate the inflammatory response. In this study we examined the role of endogenously produced IL-10 in T-helper 1 (Th1)- and Th2-type cytokine production and granuloma formation. The dynamics of IL-10 production through the course of the infection were different in granuloma versus splenic cells. In the former, production peaked during the early developmental stage (6 weeks of infection) of the granuloma and then declined. In splenocytes production peaked at 12 weeks, before down-modulation of the granuloma response. In the developing granuloma both macrophages and T cells secreted IL-10. In anti-IL-10 monoclonal antibody (mAb)-supplemented granuloma cell cultures endogenous IL-10-mediated regulation of interferon-gamma (IFN-gamma) was manifest only at 6 weeks; that of IL-2 continued throughout the infection (6-20 weeks). IL-4 production was unaffected, but IL-5 production was regulated at the 6 and 8 weeks time point. Splenocytes showed regulation of IFN-gamma and IL-2 production at the peak of the granulomatous response (8 weeks). IL-4 production was not regulated, whereas IL-5 production was regulated only at 6 weeks. Repeated injections of anti-IL-10 mAb given to mice at 6, 12 or 20 weeks of the infection significantly enhanced liver and lung granuloma growth, tissue eosinophilia, and IFN-gamma, IL-5 production at the early developmental phase (6 weeks) of the lesions. Thus, in schistosome-infected mice endogenous IL-10 is shown to regulate Th1- and Th2-type cytokine production and granuloma formation during the early Th0/Th1 phase of the immune response.     

GM-CSF, IL-1 alpha, IL-1 beta, IL-6, IL-8, IL-10, ICAM-1 and VCAM-1 gene expression and cytokine production in human duodenal fibroblasts stimulated with lipopolysaccharide, IL-1 alpha and TNF-alpha.

The role of mucosal fibroblasts in intestinal inflammatory reactions is not known. In this study, we demonstrate that fibroblasts grown from histologically normal human duodenal biopsy tissues expressed mRNA genes for granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-1 alpha, IL-1 beta, IL-6, IL-8, IL-10, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) when stimulated with lipopolysaccharide (LPS) or IL-1 alpha. The increased mRNA expression of GM-CSF, IL-1 alpha, IL-1 beta, IL-6 and IL-8 in response to IL-1 alpha and LPS stimulation was time- and dose-dependent. In contrast, IL-10 was weakly expressed when fibroblasts were stimulated with LPS, IL-1 alpha or tumour necrosis factor-alpha (TNF-alpha), but the expression was enhanced in the presence of cycloheximide combined with optimal concentrations of LPS, IL-1 alpha or TNF-alpha, IL-1 alpha was a more potent stimulator than LPS for GM-CSF, IL-6, IL-8 and IL-10 expression, but not for IL-1 alpha and IL-1 beta. Increased GM-CSF, IL-6 and IL-8 gene expression was associated with the production of cytokine proteins in culture supernatant, but IL-1 alpha and IL-1 beta remained undetectable. Dexamethasone suppressed both gene expression and protein production of GM-CSF, IL-6 and IL-8 when fibroblasts were exposed to IL-1 alpha. TNF-alpha stimulated the release of GM-CSF, IL-6 and IL-8 and, combined with IL-1 alpha, cytokine production was enhanced synergistically. Finally, both LPS and IL-1 alpha up-regulated ICAM-1 and VCAM-1 gene expression. These findings implicate duodenal fibroblasts in the initiation and/or regulation of intestinal inflammation.     

High levels of circulating IL-10 in human malaria.

IL-10 is a monocyte/lymphocyte derived cytokine which has been shown to inhibit certain cellular immune responses such as delayed hypersensitivity. In particular, the production of tumour necrosis factor (TNF), IL-1 and IL-6, which are involved in malaria pathology, are strongly inhibited by IL-10. Accordingly, we examined whether IL-10 could be involved in a human acute parasitic infection such as Plasmodium falciparum malaria. Human IL-10 levels in plasma were determined by two-site ELISA method, taking care to avoid non-specific reactions due to autoantibodies. Fourteen cerebral, 11 severe, and 20 mild malaria cases had mean IL-10 levels of 2812, 2882 and 913 pg/ml, respectively, while 98% of healthy individuals had undetectable (less than 100 pg/ml) circulating IL-10. Thirteen of the 25 cerebral/severe cases had > 2000 pg/ml. In 11 hospitalized patients, circulating IL-10 levels were found to return to virtually normal levels 7 days after antimalarial chemotherapy when biological and clinical malaria features had disappeared (mean levels fell from 3880 to 333 pg/ml). Further studies are required to determine whether these elevated levels of IL-10 play a beneficial role by reducing the parasite-induced inflammatory response, or a detrimental one by decreasing the cellular immune responses.     

Role of myeloid cells in the immunosuppressive microenvironment in gliomas

Glioma is the most common primary brain cancer, and half of patients present a diagnosis of glioblastoma (GBM), its most aggressive and lethal form. Conventional therapies, including surgery, radiotherapy, and chemotherapy, have not resulted in major ameliorations in GBM survival outcome, which remains extremely poor. Recent immunotherapy improvements for other tumors, coupled with growing knowledge of the complex interactions between malignant glioma cells and the immune system, led to an exponential increase in glioma immunotherapy research. However, immunotherapeutic strategies in GBM have not yet reached their full potential, mainly due to the limited understanding of the strong immunosuppressive microenvironment (TME) characterizing this tumor. Glioma-associated macrophages and microglia (GAMs) are key drivers of the local immunosuppression promoting tumor progression and its resistance to immunomodulating therapeutic strategies. Together with other myeloid cells, such as dendritic cells and neutrophils, GAMs actively shape glioma TME, modulate anti-tumoral immune response and support angiogenesis, tumor cell invasion and proliferation. In this review, we discuss the role of myeloid cells in the complex TME of glioma and the available clinical data on therapeutic strategies focusing on approaches that affect myeloid cells activity in GBM.     

IL-10 enhances expression of the IL-2 receptor alpha chain on T cells.

Interleukin-10 (IL-10) has various immunomodulatory actions depending on the target cell type. Some of these effects have been shown to be owing to its ability to down-regulate surface expression of markers, for example HLA-DR on macrophages and CD25 (IL-2 receptor alpha chain) on B cells. In this report we show that preincubation of IL-10 for 24 hr up-regulates expression of the activation marker CD25, but not HLA-DR on cloned T cells of various phenotypes such as CD4+, CD8+, CD4- CD8- alpha beta and gamma delta T-cell receptor (TCR)-expressing cells. This up-regulation of CD25 was accompanied by an increase in the T cells IL-2-dependent proliferative response in 63% of the CD4+ clones and 100% of the CD8+, CD4-, CD8- alpha beta and gamma delta TCR+ clones analysed. IL-10 was also shown to be at least partly responsible for the up-regulation of CD25 on mitogen-activated peripheral blood mononuclear cells, suggesting that IL-10 has this CD25 modulatory effect within a more physiological environment. Our data suggest that IL-10 can have a multitude of effects on human T cells, and should not be considered exclusively as an immunoinhibitory cytokine.