Role of IL-6 in the commitment of T cell subsets (original) (raw)

IL-6-dependent spontaneous proliferation is required for the induction of colitogenic IL-17-producing CD8+ T cells

Journal of Experimental Medicine, 2008

We propose a novel role for interleukin (IL) 6 in inducing rapid spontaneous proliferation (SP) of naive CD8+ T cells, which is a crucial step in the differentiation of colitogenic CD8+ T cells. Homeostasis of T cells is regulated by two distinct modes of cell proliferation: major histocompatibility complex/antigen–driven rapid SP and IL-7/IL-15–dependent slow homeostatic proliferation. Using our novel model of CD8+ T cell–dependent colitis, we found that SP of naive CD8+ T cells is essential for inducing pathogenic cytokine-producing effector T cells. The rapid SP was predominantly induced in mesenteric lymph nodes (LNs) but not in peripheral LNs under the influence of intestinal flora and IL-6. Indeed, this SP was markedly inhibited by treatment with anti–IL-6 receptor monoclonal antibody (IL-6R mAb) or antibiotic-induced flora depletion, but not by anti–IL-7R mAb and/or in IL-15–deficient conditions. Concomitantly with the inhibition of SP, anti–IL-6R mAb significantly inhibited ...

Human IL-6R(hi)TIGIT(-) CD4(+)CD127(low)CD25(+) T cells display potent in vitro suppressive capacity and a distinct Th17 profile

Clinical immunology (Orlando, Fla.), 2017

To date many clinical studies aim to increase the number and/or fitness of CD4(+)CD127(low)CD25(+) regulatory T cells (Tregs) in vivo to harness their regulatory potential in the context of treating autoimmune disease. Here, we sought to define the phenotype and function of Tregs expressing the highest levels of IL-6R. We have identified a population of CD4(+)CD127(low)CD25(+) TIGIT(-) T cells distinguished by their elevated IL-6R expression that lacked expression of HELIOS, showed higher CTLA-4 expression, and displayed increased suppressive capacity compared to IL-6R(hi)TIGIT(+) Tregs. IL-6R(hi)TIGIT(-) CD127(low)CD25(+) T cells contained a majority of cells demethylated at FOXP3 and displayed a Th17 transcriptional signature, including RORC (RORγt) and the capacity of producing both pro- and anti-inflammatory cytokines, such as IL-17, IL-22 and IL-10. We propose that in vivo, in the presence of IL-6-associated inflammation, the suppressive function of CD4(+)CD127(low)CD25(+) FOXP...

Enhancement of T Helper2Response in the Absence of Interleukin (IL-)6; An Inhibition of IL-4-Mediated T Helper2Cell Differentiation by IL-6

Cytokine, 2001

Functional roles of interleukin (IL-)6 in T cell response were investigated. Mice deficient in IL-6 and wild mice were immunized with antigens (myelin oligodendrocyte glycoprotein or methylated BSA) and production of IL-4 and interferon (IFN)-gamma by regional lymph nodes was measured. IL-6 deficiency led to an enhancement of IL-4 and an inhibition of IFN-gamma production. Moreover, polyclonal stimulation of spleen T cells from unimmunized IL-6-deficient mice with anti-CD3 plus anti-CD28 antibodies (Abs) demonstrated an enhancement of T helper (Th)(2)responses. The presence of IL-6, however, augmented IL-4 production but it inhibited IFN-gamma expression by spleen T cells in response to polyclonal stimulation and by antigen-primed spleen T cells in response to re-challenge with the antigen. In contrast, the induction of spleen CD4-positive T cells into Th(2)cells in vitro by the anti-CD3 plus IL-4 was completely suppressed by exogenously added IL-6, whereas Th(1)differentiation of T cells by the anti-CD3 plus IL-12 was not inhibited by the presence of IL-6. Thus, these results indicate that IL-6 physiologically could modulate qualitative T cell response and suggest that it augments Th(1)responses partly through its inhibitory capability of IL-4-induced Th(2)differentiation of naive T cells.

IL-6 controls Th17 immunity in vivo by inhibiting the conversion of conventional T cells into Foxp3+ regulatory T cells

2008

The conditions leading to the induction of adaptive Foxp3 ؉ regulatory T cells (T-regs) from peripheral T cells in vivo are incompletely understood. Here, we show that unresponsiveness of T cells to IL-6 by T cell-selective deletion of gp130 or immunization of wild-type mice with antigen in incomplete Freund's adjuvant (IFA), which fails to induce IL-6, promotes the conversion of peripheral CD4 ؉ T cells into adaptive Foxp3 ؉ T-regs. Thus, both T cell-conditional gp130 knockout (KO) mice immunized with MOG35-55 in complete Freund's adjuvant (CFA) and wild-type mice immunized with MOG35-55 in IFA develop overwhelming antigen-specific T-reg responses and are protected from experimental autoimmune encephalomyelitis (EAE). Depletion of T-regs restores T helper (Th)17 responses and clinical EAE in MOG/CFA-immunized T cell-conditional gp130 KO mice, but not in MOG/IFA-immunized wild-type mice. We conclude that in the absence of T-regs, IL-6 signaling is dispensable for the induction of Th17 cells, and alternative pathways exist to induce Th17 cells and EAE in the absence of IL-6 signaling. However, IL-6 signaling is dominant in inhibiting the conversion of conventional T cells into Foxp3 ؉ T-regs in vivo, and in the absence of IL-6 signaling, no other cytokine can substitute in inhibiting T-reg conversion. These data identify IL-6 as an important target to modulate autoimmune responses and chronic inflammation.

Interleukin-6 promotes the production of interleukin-4 and interleukin-5 by interleukin-2-dependent and -independent mechanisms in freshly isolated human T cells

Immunology, 2002

T helper 2 (Th2) cytokines [interleukin (IL)-4 and IL-5] play a central role in the development of allergic immune responses. After allergen provocation, the expression of Th2 cytokines is rapidly up-regulated in atopy and asthma. IL-6 is a multifunctional cytokine that is able to direct Th2 immune responses and is secreted by multiple tissue cell types. This study shows that IL-6 induces up-regulation of IL-4 and IL-5 after short (5 min) preincubation periods in freshly isolated, a-CD3/ a-CD28-stimulated T cells. After longer preincubation periods with IL-6 (12 and 24 hr), the priming effect on IL-4 production gradually disappears, whereas the effect on IL-5 becomes more pronounced. In contrast, a small but significant inhibitory effect is found on the production of the Th1 cytokine interferon-g. Additional experiments indicate that the long-term priming effect of IL-6 on IL-5 production is dependent on IL-2 signalling. This is not the case for the short-term IL-6 effect on IL-5 secretion, where the p38 mitogen-activated protein kinase-dependent induction of activator protein-1 DNA-binding activity is involved, independent of signal transducer and activator of transcription 3 phosphorylation. In summary, these data demonstrate that the short-term and long-term priming effects of IL-6 on Th2 cytokine production are regulated by different mechanisms.

c-Maf-dependent Treg cell control of intestinal TH17 cells and IgA establishes host–microbiota homeostasis

Nature Immunology, 2019

he intestinal immune system has evolved to maintain a symbiotic relationship with the microbiota while at the same time providing protection against pathogenic microbes. In turn, the microbiota plays a fundamental role in shaping and maintaining the intestinal immune system. Microbiota-induced IgA-secreting plasma cells and interleukin (IL)-17-and IL-22-producing helper T cells (T H 17 cells), which reside in the mucosal lamina propria (LP), are key host mediators of this crosstalk. IgA directly shapes the microbial landscape by promoting colonization with mutualistic microbes and neutralization of invasive pathogens 1. The cytokines IL-17 and IL-22 act cooperatively to maintain the mucosal barrier system and induce the expression of anti-microbial molecules in intestinal epithelial cells 2,3. Impaired IgA production, IL-22 deficiency or disruption of IL-17R signaling severely affects the balance of gut bacterial communities, resulting in dysbiosis and increased susceptibility to intestinal inflammation 4-7. Conversely, unrestrained mucosal immune responses to the microbiota are a driving force of inflammatory bowel disease 4 , necessitating a tight control on the dynamic dialog between host immune system and microbiota. Foxp3 + T reg cells are critical to maintain immune homeostasis in both lymphoid and non-lymphoid tissues. The majority of T reg cells develop in the thymus and recirculate through secondary lymphoid organs, where they undergo further differentiation in response to T cell antigen receptor (TCR) and cytokine signals 5. This process of differentiation into fully suppressive effector T reg cells (eT reg cells) is characterized by expression of the transcriptional regulator Blimp-1 and the ability to produce IL-10 (ref. 6). eT reg cell differentiation is paralleled by an increased ability to migrate into various non-lymphoid tissues, including the gastrointestinal tract, adipose tissue, lung, kidney, skin and injured muscle, where T reg cells contribute to tissue homeostasis and repair 7-10. Notably, migration into non-lymphoid c-Maf-dependent T reg cell control of intestinal T H 17 cells and IgA establishes host-microbiota homeostasis