Dataset Information

Exposure of Human CD4 T Cells to IL-12 Results in Enhanced TCR-Induced Cytokine Production, Altered TCR Signaling, and Increased Oxidative Metabolism.

ABSTRACT: Human CD4 T cells are constantly exposed to IL-12 during infections and certain autoimmune disorders. The current paradigm is that IL-12 promotes the differentiation of naïve CD4 T cells into Th1 cells, but recent studies suggest IL-12 may play a more complex role in T cell biology. We examined if exposure to IL-12 alters human CD4 T cell responses to subsequent TCR stimulation. We found that IL-12 pretreatment increased TCR-induced IFN-?, TNF-?, IL-13, IL-4 and IL-10 production. This suggests that prior exposure to IL-12 potentiates the TCR-induced release of a range of cytokines. We observed that IL-12 mediated its effects through both transcriptional and post-transcriptional mechanisms. IL-12 pretreatment increased the phosphorylation of AKT, p38 and LCK following TCR stimulation without altering other TCR signaling molecules, potentially mediating the increase in transcription of cytokines. In addition, the IL-12-mediated enhancement of cytokines that are not transcriptionally regulated was partially driven by increased oxidative metabolism. Our data uncover a novel function of IL-12 in human CD4 T cells; specifically, it enhances the release of a range of cytokines potentially by altering TCR signaling pathways and by enhancing oxidative metabolism.

SUBMITTER: Vacaflores A

PROVIDER: S-EPMC4900534 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Exposure of Human CD4 T Cells to IL-12 Results in Enhanced TCR-Induced Cytokine Production, Altered TCR Signaling, and Increased Oxidative Metabolism.

Vacaflores Aldo A Chapman Nicole M NM Harty John T JT Richer Martin J MJ Houtman Jon C D JC

PloS one 20160609 6

Human CD4 T cells are constantly exposed to IL-12 during infections and certain autoimmune disorders. The current paradigm is that IL-12 promotes the differentiation of naïve CD4 T cells into Th1 cells, but recent studies suggest IL-12 may play a more complex role in T cell biology. We examined if exposure to IL-12 alters human CD4 T cell responses to subsequent TCR stimulation. We found that IL-12 pretreatment increased TCR-induced IFN-γ, TNF-α, IL-13, IL-4 and IL-10 production. This suggests t ...[more]

PMID: 27280403

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Project description:BackgroundCD4 T lymphocyte activation requires T cell receptor (TCR) engagement by peptide/MHC (major histocompatibility complex) (pMHC). The TCR complementarity-determining region 3 (CDR3) contains variable ? and ? loops critical for pMHC recognition. During any immune response, tuning of TCR usage through progressive clonal selection occurs. Th1 and Th2 cells operate at different avidities for activation and display distinct transcriptional programs, although polarization may be plastic, influenced by pathogens and cytokines. We therefore hypothesized that CDR3?? sequence features may intrinsically influence CD4 phenotype during progression of a response.ResultsWe show that CD4 polarization involves distinct CDR3? usage: Th1 and Th17 cells favored short TCR CDR3? sequences of 12 and 11 amino acids, respectively, while Th2 cells favored elongated CDR3? loops of 14 amino acids, with lower predicted affinity. The dominant Th2- and Th1-derived TCR? sequences with 14 amino acid CDR3 loops and 12 amino acid CDR3 loops, respectively, were expressed in TCR transgenics. The functional impact of these TCR? transgenes was assessed after in vivo priming with a peptide/adjuvant. The short, Th1-derived receptor transgenic T cell lines made IFN?, but not IL-4, 5 or 13, while the elongated, Th2-derived receptor transgenic T cell lines made little or no IFN?, but increased IL-4, 5 and 13 with progressive re-stimulations, mirrored by GATA-3 up-regulation. T cells from primed Th2 TCR? transgenics selected dominant TCR V? expansions, allowing us to generate TCR?? transgenics carrying the favored, Th2-derived receptor heterodimer. Primed T cells from TCR?? transgenics made little or no IL-17 or IFN?, but favored IL-9 after priming with Complete Freund's adjuvant and IL-4, 5, 9, 10 and 13 after priming with incomplete Freund's. In tetramer-binding studies, this transgenic receptor showed low binding avidity for pMHC and polarized T cell lines show TCR avidity for Th17 > Th1 > Th2. While transgenic expression of a Th2-derived, 'elongated' TCR-CDR3? and the TCR?? pair, clearly generated a program shifted away from Th1 immunity and with low binding avidity, cytokine-skewing could be over-ridden by altering peptide challenge dose.ConclusionWe propose that selection from responding clones with distinctive TCRs on the basis of functional avidity can direct a preference away from Th1 effector responses, favoring Th2 cytokines.

Project description:Mycetoma is a neglected tropical disease, endemic in many tropical and subtropical regions, characterised by massive deformity and disability and can be fatal if untreated early and appropriately. Interleukins (IL) -35 and IL-37 are newly discovered cytokines that play an important role in suppressing the immune system. However, the expression of these interleukins in patients with Madurella mycetomatis (M. mycetomatis) induced eumycetoma has not yet been explored. The aim of this study is to determine the levels of IL-1 family (IL-1β, IL-37) and IL-12 family (IL-12, IL-35) in a group of these patients and the association between these cytokines levels and the patients' demographic characteristics. The present, case-control study was conducted at the Mycetoma Research Centre, Soba University Hospital, University of Khartoum, Sudan and it included 140 individuals. They were divided into two groups; group I: healthy controls [n = 70; median age 25 years (range 12 to 70 years)]. Group II: mycetoma patients [n = 70 patients; median age 25 (range 13 to 70 years)]. Cytokines levels were measured in sera using enzyme linked immunosorbent assay (ELISA). There was a significant negative correlation between IL-1β and IL-12 levels and lesion size and disease duration, while IL-37 and IL-35 levels were significantly positively correlated with both lesion size and disease duration. The analysis of the risk factors of higher circulatory levels of IL-37 in patients of mycetoma showed a negative significant association with IL-1β cytokine, where a unit increment in IL-1β will decrease the levels of IL-37 by 35.28 pg/ml. The levels of IL-37 among the patients with a duration of mycetoma infection ≤ 1 year were significantly low by an average of 18.45 pg/ml compared to patients with a mycetoma infection's duration of ≥ 5years (reference group). Furthermore, the risk factors of higher levels of IL-35 in mycetoma patients revealed a negative significant association with IL-12, as a unit increment in IL-12 decreases the levels of IL-35 by 8.99 pg/ml (p < 0.001). Levels of IL-35 among the patients with duration of mycetoma infection ≤ one year were significantly low on average by 41.82 pg/ml (p value = 0.002) compared to patients with a duration of mycetoma infection ≥ 5 years (reference group). In conclusion, this study indicates that both IL-35 and IL-37 are negatively associated with the levels of IL-1β and IL-12 in eumycetoma mycetoma infection; and high levels of IL-37 and IL-35 may have a negative impact on disease progression.

Dataset Information

Exposure of Human CD4 T Cells to IL-12 Results in Enhanced TCR-Induced Cytokine Production, Altered TCR Signaling, and Increased Oxidative Metabolism.

Publications

Exposure of Human CD4 T Cells to IL-12 Results in Enhanced TCR-Induced Cytokine Production, Altered TCR Signaling, and Increased Oxidative Metabolism.

Similar Datasets

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