Article

Cutting Edge: IL-12 inversely regulates T-bet and eomesodermin expression during pathogen-induced CD8

Abramson Family Cancer Research Institute and Department of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA.
The Journal of Immunology (Impact Factor: 5.36). 01/2007; 177(11):7515-9. DOI: 10.4049/jimmunol.177.11.7515
Source: PubMed

ABSTRACT Cytokines are critical determinants for specification of lineage-defining transcription factors of CD4+ T cell subsets. Little is known, however, about how cytokines regulate expression of T-bet and eomesodermin (Eomes) in effector and memory CD8+ T cells. We now report that IL-12, a signature of cell-mediated immunity, represses Eomes while positively regulating T-bet in effector CD8+ T cells during infection with Listeria monocytogenes. After resolution of infection and abatement of IL-12 signaling, Eomes expression rises whereas T-bet expression declines in memory CD8+ T cells. Eomes becomes derepressed in effector cells by ablation of IL-12 signaling. In the absence of IL-12, the dynamics of clonal expansion and contraction are also perturbed. Together, these results reveal how a pathogen-associated signal, such as IL-12, could act as a switch, regulating appropriate clonal growth and decline while, in parallel, shaping a unique pattern of fate-determining transcription factors.

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    • "T-bet is known to modulate a number of genes involved in T-cell mobilization (CXCR3), cell signaling (IL12Rβ1), and cytolytic signaling molecules (IFNγ) (8). Additionally, high levels of T-bet expression are closely associated with cytotoxic CD8+ T-cell effector differentiation and function, including the upregulation of perforin and granzyme B in antigen-specific cells (9–12). T-bet has been implicated in sustaining memory subsets (13–16), however, T-bet levels decline as cells become more memory-like (17). "
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    ABSTRACT: The T-box transcription factors T-bet and Eomesodermin (Eomes) have been well defined as key drivers of immune cell development and cytolytic function. While the majority of studies have defined the roles of these factors in the context of murine T-cells, recent results have revealed that T-bet, and possibly Eomes, are expressed in other immune cell subsets. To date, the expression patterns of these factors in subsets of human peripheral blood mononuclear cells beyond T-cells remain relatively uncharacterized. In this study, we used multiparametric flow cytometry to characterize T-bet and Eomes expression in major human blood cell subsets, including total CD4(+) and CD8(+) T-cells, γδ T-cells, invariant NKT cells, natural killer cells, B-cells, and dendritic cells. Our studies identified novel cell subsets that express T-bet and Eomes and raise implications for their possible functions in the context of other human immune cell subsets besides their well-known roles in T-cells.
    Frontiers in Immunology 05/2014; 5:217. DOI:10.3389/fimmu.2014.00217
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    • "For instance, activation of CD8+ cells also primarily depends on glycolysis [23], and differentiation of effector CD8+ cells requires mTORC1-dependent T-bet expression [24]. Most critically, mTOR is involved in the transition of effector to memory CD8+ T cells (Figure 2), and this appears to rely on conversion of T-bet to eomesodermin transcription factor expression [24-26]; blocking mTOR with rapamycin has this exact effect, and therefore promotes the development and sustenance of memory T cells that transition efficiently into effector cells highly capable of producing immune responses to, for instance, tumours [24]. Similar to Treg cells, memory CD8+ T cells depend on mitochondrial oxidative phosphorylation for energy (rather than glycolysis) and are driven by STAT5 signalling. "
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    11/2013; 2(Suppl 1):S2. DOI:10.1186/2047-1440-2-S1-S2
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    • "We investigated several traditional pathways involved in memory CTL differentiation, including T-bet/Eomes and mTOR signaling. Upregulated T-bet expression is related to effector CTL function whereas Eomes upregulation drives CTLs toward memory functions [24], [46]. In this study, nicotine did not alter the T-bet/Eomes ratio (Fig. 5). "
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    ABSTRACT: Nicotine is the main tobacco component responsible for tobacco addiction and is used extensively in smoking and smoking cessation therapies. However, little is known about its effects on the immune system. We confirmed that multiple nicotinic receptors are expressed on mouse and human cytotoxic T lymphocytes (CTLs) and demonstrated that nicotinic receptors on mouse CTLs are regulated during activation. Acute nicotine presence during activation increases primary CTL expansion in vitro, but impairs in vivo expansion after transfer and subsequent memory CTL differentiation, which reduces protection against subsequent pathogen challenges. Furthermore, nicotine abolishes the regulatory effect of rapamycin on memory CTL programming, which can be attributed to the fact that rapamycin enhances expression of nicotinic receptors. Interestingly, naïve CTLs from chronic nicotine-treated mice have normal memory programming, which is impaired by nicotine during activation in vitro. In conclusion, simultaneous exposure to nicotine and antigen during CTL activation negatively affects memory development.
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