Project description:TOX is a member of the HMG-Box transcription factors and plays important roles in thymic T cell development. Outside of the thymus, however, TOX is also highly expressed by CD8 and CD4 T cells in various states of activation and in settings of cancer and autoimmune disease. In CD4 T cells, TOX has been primarily studied in T follicular helper (TFH) cells where it , along with TOX2 promotes TFH differentiation by regulating key TFH-associated genes and suppressing CD4 cytotoxic T cell differentiation. However, the role of TOX in other Th cell subtypes is less clear. In our study, we show that TOX is expressed in several physiologically-activated Th subtypes and its ectopic expression modestly enhances the in vitro differentiation of Th2 and Treg cells. TOX overexpression also induced the expression of a small number of genes in unpolarized Th cells involved in cell activation (Pdcd1, PD-1), cellular trafficking (Ccl3, Ccl4, Xcl1) and in suppressing inflammation (Il10) that was conserved in multiple Th subtypes. We additionally show that TOX co-occupies these genes with the transcription factor BATF and that TOX-induced expression of IL-10, but not PD-1, is BATF-dependent. Based on these data, we propose a model where TOX regulates Th cell chemotactic genes involved in facilitating dendritic cell-T cell interactions and aids in the resolution or prevention of inflammation through the production of IL-10.
Project description:BackgroundIL-10 is a cytokine mainly produced by macrophages that plays key roles in tolerance to inhaled antigens and in lung homeostasis. Its regulation in alveolar macrophages (HAM), the resident lung phagocytes, remains however unknown.MethodsThe present study investigated the role of intracellular signalling and transcription factors controlling the production of IL-10 in LPS-activated HAM from normal nonsmoking volunteers.ResultsLPS (1-1000 pg/ml) induced in vitro IL-10 production by HAM, both at mRNA and protein levels. LPS also activated the phosphorylation of ERK, p38 and JNK MAPkinases (immunoblots) and Sp-1 nuclear activity (EMSA). Selective inhibitors of MAPKinases (respectively PD98059, SB203580 and SP600125) and of Sp-1 signaling (mithramycin) decreased IL-10 expression in HAM. In addition, whilst not affecting IL-10 mRNA degradation, the three MAPKinase inhibitors completely abolished Sp-1 activation by LPS in HAM.ConclusionThese results demonstrate for the first time that expression of IL-10 in lung macrophages stimulated by LPS depends on the concomitant activation of ERK, p38 and JNK MAPKinases, which control downstream signalling to Sp-1 transcription factor. This study further points to Sp-1 as a key signalling pathway for IL-10 expression in the lung.
Project description:Regulatory T cells (T(reg)) are believed to suppress conventional T cell (T(conv)) proliferation in vitro in a contact-dependent, cytokine-independent manner, based in part on experiments in which T(reg) and T(conv) are separated by a permeable membrane. We show that the production of IL-35, a novel inhibitory cytokine expressed by natural T(reg), increases substantially following contact with T(conv). Surprisingly, T(reg) were able to mediate potent suppression of T(conv) across a permeable membrane when placed in direct contact with T(conv) in the upper chamber of a Transwell plate. Suppression was IL-35 and IL-10 dependent, and T(conv) activation was required for maximal potentiation of T(reg) suppression. These data suggest that it is the induction of suppression, rather than the function of T(reg) that is obligatorily contact dependent.
Project description:Natural killer (NK) cells can produce IFNγ or IL-10 to regulate inflammation and immune responses but the factors driving NK cell IL-10 secretion are poorly-defined. Here, we identified NK cell-intrinsic STAT3 activation as vital for IL-10 production during both systemic Listeria monocytogenes (Lm) infection and following IL-15 cytokine/receptor complex (IL15C) treatment for experimental cerebral malaria (ECM). In both contexts, conditional Stat3 deficiency in NK cells abrogated production of IL-10. Initial NK cell STAT3 phosphorylation was driven by IL-15. During Lm infection, this required capture or presentation of IL-15 by NK cell IL-15Rα. Persistent STAT3 activation was required to drive measurable IL-10 secretion and required NK cell expression of IL-10Rα. Survival-promoting effects of IL-15C treatment in ECM were dependent on NK cell Stat3 while NK cell-intrinsic deficiency for Stat3, Il15ra, or Il10ra abrogated NK cell IL-10 production and increased resistance against Lm. NK cell Stat3 deficiency did not impact production of IFNγ, indicating the STAT3 activation initiated by IL-15 and amplified by IL-10 selectively drives the production of anti-inflammatory IL-10 by responding NK cells.
Project description:CD8(+) T cells play an important role in immune regulation and effective immune responses against tumor cells, viral infection, and intracellular pathogens. In this report, using tiger or 10BiT mice, we defined a population of IL-10-producing CD8(+) T cells that were induced by IL-4. These IL-10(+)CD8(+) T cells possessed a strong inhibitory effect on the CD4(+) T cell proliferation in an IL-10-dependent and cell contact-dependent fashion. In comparison with IL-10(-)CD8(+) T cells, IL-10(+)CD8(+) T cells expressed an array of Th2-like cytokines (IL-4, IL-5), perforin, and granzymes, as well as the cell cycle regulatory protein Cdkn2a. Interestingly, knockdown of cdkn2a using siRNA reduced IL-4-induced IL-10 production significantly. Furthermore, CD8(+) T cells from Cdkn2a(-/-) mice produced a significantly lower amount of IL-10, and the effect was limited to CD8(+) T cells but not observed in CD4(+) T cells and APCs. Finally, IL-10(+)CD8(+) T cells played a protective role in the TNBS-induced murine colitis model, indicating a critical role of this population of CD8(+) T cells in regulatory immune responses. Taken together, we have defined a population of IL-10-producing CD8(+) Tregs induced by IL-4 and mediated by Cdkn2a.
Project description:Basophils play a key role in the development and effector phases of type 2 immune responses in both allergic diseases and helminth infections. This study shows that basophils become less responsive to IgE-mediated stimulation when mice are chronically infected with Litomosoides sigmodontis, a filarial nematode, and Schistosoma mansoni, a blood fluke. Although excretory/secretory products from microfilariae of L. sigmodontis suppressed basophils in vitro, transfer of microfilariae into mice did not result in basophil suppression. Rather, reduced basophil responsiveness, which required the presence of live helminths, was found to be dependent on host IL-10 and was accompanied by decreases in key IgE signaling molecules known to be downregulated by IL-10. Given the importance of basophils in the development of type 2 immune responses, these findings help explain the mechanism by which helminths protect against allergy and may have broad implications for understanding how helminth infections alter other disease states in people.
Project description:Tuberculosis, caused by the intracellular bacterium Mycobacterium tuberculosis, currently causes ∼1.4 million deaths per year, and it therefore remains a leading global health problem. The immune response during tuberculosis remains incompletely understood, particularly regarding immune factors that are harmful rather than protective to the host. Overproduction of the type I IFN family of cytokines is associated with exacerbated tuberculosis in both mouse models and in humans, although the mechanisms by which type I IFN promotes disease are not well understood. We have investigated the effect of type I IFN on M. tuberculosis-infected macrophages and found that production of host-protective cytokines such as TNF-α, IL-12, and IL-1β is inhibited by exogenous type I IFN, whereas production of immunosuppressive IL-10 is promoted in an IL-27-independent manner. Furthermore, much of the ability of type I IFN to inhibit cytokine production was mediated by IL-10. Additionally, type I IFN compromised macrophage activation by the lymphoid immune response through severely disrupting responsiveness to IFN-γ, including M. tuberculosis killing. These findings describe important mechanisms by which type I IFN inhibits the immune response during tuberculosis.
Project description:Mast cells (MCs) are tissue-resident cells of hematopoietic origin that play an important role in host's defense mechanism against nematodes. However, excessive activation of these cells contributes to the development of certain allergic diseases. Immunoglobin E (IgE) is one of the well-known molecules that activate MCs. Even in the absence of specific antigens, the binding of highly cytokinergic IgE to FcεRI on MCs prolongs their survival and induces cytokine production without enhancing their degranulation. In the present study, we examined the effects of the members of the interleukin-10 (IL-10) family of cytokines on IgE-mediated MCs functions. The receptors including Il10r1, Il10r2, and Il20r2, but not Il20r1, Il22r1 or Il28r1, were constitutively expressed in mouse bone marrow cell-derived cultured MCs (BMCMCs), suggesting that IL-10 may influence MCs function. Indeed, we found that only IL-10 could influence upon BMCMCs function; IL-10 enhanced prolongation of survival, promoted IL-6 and/or IL-13 production dependently of STAT1 and STAT3, and suppressed tumor necrosis factor production independently of STAT1 and STAT3 on IgE-stimulated BMCMCs. Moreover, the IL-10-mediated enhancement of IL-6 production by IgE-stimulated BMCMCs promotes Th17 cell expansion. These results suggest that IL-10 has a dual role as an anti-inflammatory and pro-inflammatory cytokine in MCs functions.
Project description:Interleukin (IL)-10 is an important regulatory cytokine that can modulate excessive immune mediated injury. Several distinct cell types have been demonstrated to produce IL-10, including most recently CD8+ cytotoxic T lymphocytes (CTLs) responding to respiratory virus infection. Here we report that CD4+ T cell help in the form of IL-2 is required for IL-10 production by CTLs, but not for the induction of CTL effector cytokines. We show that IL-2 derived from CD4+ helper T cells cooperates with innate immune cell-derived IL-27 to amplify IL-10 production by CTLs through a Blimp-1-dependent mechanism. These findings reveal a previously unrecognized pathway that coordinates signals derived from innate and helper T cells to control the production of a regulatory cytokine by CTLs during acute viral infection.