Search

Objective: We previously showed that infusing rats with a solution of ethyl pyruvate ameliorates intestinal mucosal injury after mesenteric ischemia and reperfusion. Ethyl pyruvate also has been shown to inhibit the expression of various pro-inflammatory cytokines in several animal models of critical illness, but dose-response relationships have not been investigated.Design: Anesthetized C57BL/6 mice were subjected to 60 min of mesenteric ischemia followed by 60 min of reperfusion. After 55 min of ischemia, groups of mice were treated with normal saline or graded bolus doses of ethyl pyruvate dissolved in a calcium-containing balanced salt solution. Some animals (i.e., those in the sham group) were subjected to the anesthetic, but not mesenteric ischemia/reperfusion. Gut mucosal permeability was assessed using an everted gut sac technique.Setting: University research laboratory.Measurements and Results: Mesenteric ischemia/reperfusion significantly increased ileal mucosal permeability to the hydrophilic macromolecule, fluorescein isothiocyanate dextran (molecular mass 4,000 Da). Whereas the lowest dose of ethyl pyruvate evaluated (17 mg/kg) had no effect on gut mucosal permeability, the two highest doses tested (50 and 150 mg/kg) significantly ameliorated the development of ischemia/reperfusion-induced mucosal hyperpermeability to about the same extent. The two highest doses of ethyl pyruvate also significantly ameliorated deficits in ileal serosal and mucosal and hepatic surface microvascular perfusion induced by mesenteric ischemia/reperfusion. Ethyl pyruvate inhibited post-ischemia/reperfusion hepatic NF-kappaB activation and TNF mRNA expression in a dose-dependent fashion.Conclusion: Doses of ethyl pyruvate equal to or greater than 50 mg/kg ameliorate inflammation, microvascular hypoperfusion and gut mucosal damage induced by mesenteric ischemia/reperfusion in mice. [ABSTRACT FROM AUTHOR]

Studies in mice have shown that CD70 on dendritic cells (DCs) is sufficient to convert T-cell tolerance into immunity and hence induce anti-tumour immune responses. Therefore, it is important to investigate (i) optimal stimuli to induce CD70 on human monocyte-derived DCs (MoDCs), which are widely used for tumour immunotherapy, and (ii) the role of CD70 in functional differentiation of naive CD4+ and CD8+ T cells stimulated with MoDCs. We show that interferon-α (IFN-α) is a key cytokine to differentiate monocytes into DCs with the capacity to express CD70 upon maturation. CD70 expression on IFN-α-induced MoDCs was elicited by different categories of maturation-inducing factors (Toll-like receptor ligands, CD40 ligand and pro-inflammatory mediators), among which prostaglandin E2 was most effective. Naive T cells stimulated with MoDCs also expressed CD70. Stimulation with MoDCs promoted naive CD4+ T cells to acquire the ability to produce T helper type 1 and 2 cytokines in a CD70-dependent manner. In contrast, the CD70–CD27 interaction diminished the production of an immunoregulatory cytokine IL-10. The CD27 signal did not play a dominant role in the induction of effector molecules in naive CD8+ T cells during the stimulation with MoDCs. This study adds a novel function to the versatile cytokines, type I IFNs, that is, the induction of CD70 on MoDCs. CD70 promotes naive CD4+ T cells to acquire immunostimulatory activity through the DC–T-cell and T-cell–T-cell interactions during the stimulation with MoDCs. Hence, the CD70–CD27 interaction may play an important role in inducing effective immune responses in DC-based immunotherapy. [ABSTRACT FROM AUTHOR]

CD70 expressed on dendritic cells (DCs) has been shown to play a critical role in inducing effective CD8+ T cell responses and a Th1 response in mice. However, it has not been extensively examined whether human primary DCs express CD70 and whether the CD70–CD27 interaction promotes naive CD4+ T cells to acquire the ability to produce effector cytokines during the DC–T cell interaction in humans. Here, we show that human myeloid dendritic cells (mDCs) and plasmacytoid dendritic cells stimulated with CD40 ligand together with pro-inflammatory cytokines or Toll-like receptor ligands express CD70. Thymic stromal lymphopoietin plus prostaglandin E2 also induced CD70 on mDCs. Naive CD4+ T cells stimulated with DCs but not with anti-CD3/CD28 microbeads expressed CD70. Stimulation with CD70 together with anti-CD3/CD28 microbeads imparted the ability to produce Th1 (IFN-γ), Th2 (IL-4, IL-5, IL-13) cytokines, IL-2 and tumor necrosis factor-α to naive CD4+ T cells. The production of IFN-γ was associated with the induction of T-bet. Naive CD4+ T cells stimulated with mDCs acquired an enhanced ability to produce a broad array of immunostimulatory cytokines in a CD70-dependent manner. These data suggest that human CD70 expressed on mDCs and activated T cells transmits a ‘basal level’ signal, rather than a ‘polarizing’ signal, to naive CD4+ T cells, in that CD70 promotes the development of CD4+ T cells that produce a variety of effector cytokines including both Th1 and Th2 types, thus contributing to the enhancement of a broad spectrum of immune responses. [ABSTRACT FROM PUBLISHER]

Sweet syndrome is a multisystem inflammatory disorder characterized by acute fever, as well as painful erythematous plaques infiltrated with mature neutrophils in the absence of vasculitis. The pathogenesis of the disease has not yet been clarified, although several proinflammatory cytokines have been reported to be involved in the disease process. We describe here a patient clinically diagnosed with Sweet syndrome with chronic myelogenous leukemia. The mutational analysis of the patient revealed a compound heterozygous E148Q/R202Q mutation in exon 2 of MEFV gene, which is a causative gene for familial Mediterranean fever. This is the first report to describe MEFV gene mutations in Sweet syndrome. Our results suggest that Sweet syndrome may be mediated though similar inflammatory mechanisms to those of familial Mediterranean fever. Copyright © 2008 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: Lipopolysaccharide (LPS)-induced reactive oxygen species (ROS) generation and the concomitant decline in the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) were demonstrated in human monocyte-derived dendritic cells (DC). Further, their relation to the maturation of DC, characterized by the production of cytokines, up-regulation of cell surface molecules and allo-stimulatory capacity, was examined. The LPS-induced ROS generation was demonstrated using electron paramagnetic resonance spectroscopy in intact cells, and was also confirmed using laser scanning confocal microscopy. The GSH/GSSG was assesed using a glutathione assay kit. When the DC were treated with α-phenyl-tert-butylnitrone, the ROS generation was attenuated, but the declined GSH/GSSG was not attenuated, and only cytokine production was suppressed among the above-mentioned maturation characteristics. When the DC were treated with glutathione monoethyl ester, both the ROS generation and the declined GSH/GSSG were attenuated, and the maturation characteristics were all suppressed. These findings suggest that the LPS-induced ROS generation and the concomitant decline in GSH/GSSG occur in human monocyte-derived DC and that the former is involved in cytokine production, while the latter is involved in the up-regulation of cell surface molecules and allo-stimulatory capacity. Since the cytokine production and the allo-stimulatory capacity of DC play an important role in inflammatory and immune responses, differential regulation of the ROS generation and the declined GSH/GSSG may be useful as therapeutic tools in diseases where both responses become entangled, such as sepsis and graft-versus-host disease. [Copyright &y& Elsevier]

Adult T-cell leukaemia (ATL) is caused by human T-cell leukaemia virus type I (HTLV-I). It has been suggested that cytokines play a role in the development and in the neoplastic cell growth of ATL. However, the precise mechanism involved in this process still remains unclear. Interleukin-21 (IL-21) and its receptor (IL-21R) have been recently described. In this study, we examined the expression of IL-21R and the effect of IL-21 on ATL cells. Real-time reverse transcription polymerase chain reaction showed that HTLV-I-infected cell lines and primary ATL cells expressed IL-21R mRNA. Cell surface expression of IL-21R on these cells was confirmed by flow cytometric analysis using a newly developed monoclonal antibody against human IL-21R. In contrast to the expression of IL-21R, IL-21 mRNA was scarcely detectable in these cells. Notably, IL-21 induced the proliferation of ATL-43T and ED-40515(+) cells, both of which were derived from leukaemic cell clones of ATL. Concerning the intracellular signalling pathways, IL-21 activated the phosphorylation of the signal transducers and activators of transcription (STAT)3 and STAT5. Taken together, these findings provide the first evidence that ATL cells express functional IL-21R, suggesting that it may contribute to the pathophysiology of ATL. In addition, the IL-21/IL-21R system may represent a new target for the treatment of ATL. [ABSTRACT FROM AUTHOR]

Recent studies have shown that human myeloid leukaemia cells can differentiate into dendritic cell (DC)-like cells (leukaemia-DCs) when cultured with a combination of cytokines. In the present study, we examined whether the transduction of leukaemia-DCs with OX40 ligand (OX40L), a member of the tumour necrosis factor (TNF) family, resulted in augmentation of their antigen presenting activity. Bicistronic retroviral vectors expressing both human OX40L and enhanced green fluorescent protein (EGFP) or EGFP alone were generated and used for transduction. Fresh leukaemic cells from five patients with acute myeloid leukaemia (AML) were isolated and retrovirally transduced with OX40L during the culture with a combination of cytokines from stem cell factor, fms-like tyrosine kinase (Flt)-3 ligand, granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin-4 (IL-4) and TNF- α. After 7 d, the majority of cells showed DC-like morphology, and expressed higher levels of CD80, CD86 and HLA-DR than fresh leukaemic cells. The transduction efficiency was 8·5–27·2%. Leukaemia-DCs transduced with OX40L elicited higher proliferative response of allogeneic CD4+ T cells than fresh leukaemic cells, non-transduced, or mock-transduced leukaemia-DCs. Co-culture of allogeneic CD4+ T cells with OX40L-transduced leukaemia-DCs was superior in the generation of interferon (IFN)- γ producing CD4+ T cells and in production of IFN- γ. Furthermore, OX40L-transduced leukaemia-DCs could elicit significant proliferative response of human leucocyte antigen-matched T cells from the donor in allogeneic stem cell transplantation. These results indicate that retroviral transduction of leukaemia-DCs with OX40L augments their antigen presenting cell activity and thus renders them more suitable for tumour vaccines or ex vivo stimulation of leukaemia-specific T cells. [ABSTRACT FROM AUTHOR]