APVV-0737-12), Slovak VEGA Grant 2/0089/13 and EEA Grant SAV-FM-EHP-2008-02-06. MS and IS performed the research, VH and PAN analysed the data, and PAN wrote the paper with help from VH and MS. “
“Interleukin-27 (IL-27) suppresses immune responses through Cilomilast mouse inhibition of the development of IL-17 producing Th17 cells and induction of IL-10 production. We previously showed that forced expression of early growth response gene 2 (Egr-2), a transcription factor required for T-cell anergy induction,

induces IL-10 and lymphocyte activation gene 3 expression and confers regulatory activity on CD4+ T cells in vivo. Here, we evaluated the role of Egr-2 in IL-27-induced IL-10 production. Among various IL-10-inducing factors, only IL-27 induced high levels of Egr-2 and lymphocyte activation gene 3 expression. Intriguingly, IL-27 failed to induce IL-10 in Egr-2-deficient T cells. IL-27-mediated induction of Prdm1 that Stem Cell Compound high throughput screening codes B lymphocyte induced maturation protein-1, a transcriptional regulator important for IL-10 production in CD4+ T cells, was also impaired in the absence of Egr-2. Although IL-27-mediated IL-10 induction was dependent

on both STAT1 and STAT3, only STAT3 was required for IL-27-mediated Egr-2 induction. These results suggest that IL-27 signal transduction through Egr-2 and B lymphocyte induced maturation protein-1 plays an important role in IL-10 production. Furthermore, Egr-2-deficient CD4+ T cells showed dysregulated production of IFN-γ and IL-17 in response to IL-27 stimulation. Therefore, Egr-2 may play key roles in controlling the balance between regulatory and effector cytokines. Naïve CD4+ T cells play central roles in immune regulation by differentiating into effector as well as Treg-cell subsets. Recently, a number of Treg-cell subsets, which are important for suppressing effector T cells, tissue inflammation, and autoimmunity, have also been identified. On one hand, CD4+CD25+ Treg cells, which express the transcription factor Foxp3, BCKDHA have a dominant function in immune suppression and the maintenance of immune homeostasis [1, 2].

On the other hand, other Treg cells, which arise in the periphery, such as Treg type I (Tr1) cells and Th3 cells produce the suppressive cytokines IL-10 and TGF-β1, and contribute to the suppression of immune responses in a Foxp3-independent manner [3, 4]. IL-10 is an anti-inflammatory cytokine which was initially described as a cytokine associated with Th2 cells that inhibits the production of IFN-γ by Th1 cells [5, 6]. A number of reports have revealed that IL-10 suppresses cytokine production and proliferation of T cells [7, 8] and inhibits the T-cell-stimulating capacity of APCs [9]. IL-10-deficient mice die with spontaneously developed inflammatory bowel disease [10]. Interleukin-27 (IL-27), a member of the IL-12/IL-23 hetero-dimeric family of cytokines produced by APCs, is composed of two chains, p28 and EBV-induced gene 3 [11].