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1.  Imbalance in distribution of functional autologous regulatory T cells in rheumatoid arthritis 
Annals of the Rheumatic Diseases  2007;66(9):1151-1156.
Regulatory T cells (Tregs) exert their anti‐inflammatory activity predominantly by cell contact‐dependent mechanisms. A study was undertaken to investigate the regulatory capacity of autologous peripheral blood Tregs in contact with synovial tissue cell cultures, and to evaluate their presence in peripheral blood, synovial tissue and synovial fluid of patients with rheumatoid arthritis (RA).
44 patients with RA and 5 with osteoarthritis were included in the study. The frequency of interferon (IFN)γ‐secreting cells was quantified in synovial tissue cell cultures, CD3‐depleted synovial tissue cell cultures, synovial tissue cultures co‐cultured with autologous CD4+ and with CD4+CD25+ peripheral blood T cells by ELISPOT. Total CD3+, Th1 polarised and Tregs were quantified by real‐time PCR for CD3ε, T‐bet and FoxP3 mRNA, and by immunohistochemistry for FoxP3 protein.
RA synovial tissue cell cultures exhibited spontaneous expression of IFNγ which was abrogated by depletion of CD3+ T cells and specifically reduced by co‐culture with autologous peripheral blood Treg. The presence of Treg in RA synovitis was indicated by FoxP3 mRNA expression and confirmed by immunohistochemistry. The amount of FoxP3 transcripts, however, was lower in the synovial membrane than in peripheral blood or synovial fluid. The T‐bet/FoxP3 ratio correlated with both a higher grade of synovial tissue lymphocyte infiltration and higher disease activity.
This study has shown, for the first time in human RA, the efficacy of autologous Tregs in reducing the inflammatory activity of synovial tissue cell cultures ex vivo, while in the synovium FoxP3+ Tregs of patients with RA are reduced compared with peripheral blood and synovial fluid. This local imbalance of Th1 and Treg may be responsible for repeated rheumatic flares and thus will be of interest as a target for future treatments.
PMCID: PMC1955165  PMID: 17392348
2.  Simultaneous and Dose Dependent Melanoma Cytotoxic and Immune Stimulatory Activity of Betulin 
PLoS ONE  2015;10(3):e0118802.
Conventional cytostatic cancer treatments rarely result in the complete eradication of tumor cells. Therefore, new therapeutic strategies focus on antagonizing the immunosuppressive activity of established tumors. In particular, recent studies of antigen-loaded dendritic cells (DCs) eliciting a specific antitumor immune response has raised the hopes of achieving the complete elimination of tumor tissue. Genistein, fingolimod and betulin have already been described as active compounds in different types of cancer. Herein, we applied an integrated screening approach to characterize both their cytostatic and their immune-modulating properties side-by-side. As will be described in detail, our data confirmed that all three compounds exerted proapoptotic and antiproliferative activity in different B16 melanoma cell lines to a given extent, as revealed by an MTT assay, CFSE and DAPI staining. However, while genistein and fingolimod also affected the survival of primary bone marrow (BM) derived DCs of C57BL/6 mice, betulin exhibited a lower cytotoxicity for BMDCs in comparison to the melanoma cells. Moreover, we could show for the first time, that only betulin caused a simultaneous, highly specific immune-stimulating activity, as measured by the IL-12p70 release of Toll-like receptor 4-stimulated BMDCs by ELISA, which was due to increased IL-12p35 mRNA expression. Interestingly, the activation of DCs resulted in enhanced T lymphocyte stimulation, indicated by increased IL-2 and IFN-γ production of cytotoxic T cells in spleen cell co-culture assays which led to a decreased viability of B16 cells in an antigen specific model system. This may overcome the immunosuppressive environment of a tumor and destroy tumor cells more effectively in vivo if the immune response is specific targeted against the tumor tissue by antigen-loaded dendritic cells. In summary, cytostatic agents, such as betulin, that simultaneously exhibit immune stimulatory activity may serve as lead compounds and hold great promise as a novel approach for an integrated cancer therapy.
PMCID: PMC4355578  PMID: 25756279
4.  CXCL10 promotes liver fibrosis by prevention of NK cell mediated hepatic stellate cell inactivation 
Journal of autoimmunity  2010;35(4):10.1016/j.jaut.2010.09.003.
Chemokines, such as CXCL10, promote hepatic inflammation in chronic or acute liver injury through recruitment of leukocytes to the liver parenchyma. The CXCL10 receptor CXCR3, which is expressed on a subset of leukocytes, plays an important part in Th1-dependent inflammatory responses. Here, we investigated the role of CXCL10 in chemically induced liver fibrosis. We used carbon tetrachloride (CCl4) to trigger chronic liver damage in wildtype C57BL/6 and CXCL10-deficient mice. Fibrosis severity was assessed by Sirius Red staining and intrahepatic leukocyte subsets were investigated by immunohisto-chemistry. We have further analyzed hepatic stellate cell (HSC) distribution and activation and investigated the effect of CXCL10 on HSC motility and proliferation. In order to demonstrate a possible therapeutic intervention strategy, we have examined the anti-fibrotic potential of a neutralizing anti-CXCL10 antibody. Upon CCl4 administration, CXCL10-deficient mice showed massively reduced liver fibrosis, when compared to wildtype mice. CXCL10-deficient mice had less B- and T lymphocyte and dendritic cell infiltrations within the liver and the number and activity of HSCs was reduced. In contrast, natural killer (NK) cells were more abundant in CXCL10-deficient mice and granzyme B expression was increased in areas with high numbers of NK cells. Further detailed analysis revealed that HSCs express CXCR3, respond to CXCL10 and secrete CXCL10 when stimulated with IFNγ. Blockade of CXCL10 with a neutralizing antibody exhibited a significant anti-fibrotic effect. Our data suggest that CXCL10 is a pro-fibrotic factor, which participates in a crosstalk between hepatocytes, HSCs and immune cells. NK cells seem to play an important role in controlling HSC activity and fibrosis. CXCL10 blockade may constitute a possible therapeutic intervention for hepatic fibrosis.
PMCID: PMC3855675  PMID: 20932719
Hepatic fibrosis; Inflammation; Cellular trafficking; Hepatitis; Chemokine
5.  Blockade but Not Overexpression of the Junctional Adhesion Molecule C Influences Virus-Induced Type 1 Diabetes in Mice 
PLoS ONE  2013;8(1):e54675.
Type 1 diabetes (T1D) results from the autoimmune destruction of insulin-producing beta-cells in the pancreas. Recruitment of inflammatory cells is prerequisite to beta-cell-injury. The junctional adhesion molecule (JAM) family proteins JAM-B and JAM–C are involved in polarized leukocyte transendothelial migration and are expressed by vascular endothelial cells of peripheral tissue and high endothelial venules in lympoid organs. Blocking of JAM-C efficiently attenuated cerulean-induced pancreatitis, rheumatoid arthritis or inflammation induced by ischemia and reperfusion in mice. In order to investigate the influence of JAM-C on trafficking and transmigration of antigen-specific, autoaggressive T-cells, we used transgenic mice that express a protein of the lymphocytic choriomeningitis virus (LCMV) as a target autoantigen in the β-cells of the islets of Langerhans under the rat insulin promoter (RIP). Such RIP-LCMV mice turn diabetic after infection with LCMV. We found that upon LCMV-infection JAM-C protein was upregulated around the islets in RIP-LCMV mice. JAM-C expression correlated with islet infiltration and functional beta-cell impairment. Blockade with a neutralizing anti-JAM-C antibody reduced the T1D incidence. However, JAM-C overexpression on endothelial cells did not accelerate diabetes in the RIP-LCMV model. In summary, our data suggest that JAM-C might be involved in the final steps of trafficking and transmigration of antigen-specific autoaggressive T-cells to the islets of Langerhans.
PMCID: PMC3556033  PMID: 23372751
6.  Failure of Interferon γ to Induce the Anti-Inflammatory Interleukin 18 Binding Protein in Familial Hemophagocytosis 
PLoS ONE  2010;5(1):e8663.
Familial hemophagocytosis (FHL) is a rare disease associated with defects in proteins involved in CD8+ T-cell cytotoxicity. Hyperactivation of immune cells results in a perilous, Th1-driven cytokine storm. We set out to explore the regulation of cytokines in an FHL patient who was clinically stable on low-dose immunosuppressive therapy after bone marrow transplantation over a six-month period. During this period, chimerism analyses showed that the fraction of host cells was between 1 and 10%. Both parents of the patient as well as healthy volunteers were studied for comparison.
Methods/Principal Findings
Using ELISA, quantitative real-time PCR, and clinical laboratory methods, we investigated constitutive and inducible cytokines, polymorphisms, and clinical parameters in whole blood and whole blood cultures. Although routine laboratory tests were within the normal range, the chemokines IP-10 and IL-8 as well as the cytokine IL-27p28 were increased up to 10-fold under constitutive and stimulated conditions compared to healthy controls. Moreover, high levels of IFNγ and TNFα were produced upon stimulation. Unexpectedly, IFNγ induction of IL-18 binding protein (IL-18BP) was markedly reduced (1.6-fold vs 5-fold in controls). The patient's mother featured intermediately increased cytokine levels, whereas levels in the father were similar to those in the controls.
Since IL-18 plays a major role in perpetuating hemophagocytosis, the failure of IFNγ to induce IL-18BP may constitute a fundamental pathogenetic mechanism. Furthermore, increased production of IL-8 and IL-27 appears to be associated with this disease. Such dysregulation of cytokines was also found in the heterozygous parents, providing a novel insight into genotype-phenotype correlation of FHL which may encourage future research of this rare disease.
PMCID: PMC2800185  PMID: 20072626

Results 1-6 (6)