scholarly journals Inhibition of activation of transcription factor AP-1 by CD28 signalling in human T-cells

1994 ◽  
Vol 302 (1) ◽  
pp. 119-123 ◽  
Author(s):  
M Los ◽  
W Dröge ◽  
K Schulze-Osthoff
Keyword(s):  
T Cells ◽  
Transcription Factor ◽  
T Cell ◽  
Dna Binding ◽  
T Cell Activation ◽  
Cell Activation ◽  
Interleukin 2 ◽  
Regulatory Region ◽  
Nf Kappa B ◽  
Stimulation Of

Co-stimulation of T-lymphocytes by T-cell receptor (TcR) occupancy and activation of the CD28 surface molecule results in enhanced proliferation and interleukin 2 (IL-2) production. The increase in IL-2 gene expression triggered by CD28 involves a kappa B-like sequence in the 5′-regulatory region of the IL-2 promoter, called CD28-responsive element. Stimulation of T-cells by agonistic anti-CD28 antibodies in conjunction with phorbol 12-myristate 13-acetate (PMA)- or TcR-derived signals induces the enhanced activation of the transcription factor NF-kappa B. Here we report that CD28 engagement, however, exerts opposite effects on the transcription factor AP-1. Whereas anti-CD28 together with PMA increased the DNA binding and trans-activation activity of NF-kappa B, PMA-induced activation of AP-1 was significantly suppressed. The inhibitory effect exerted by anti-CD28 was observed at the level of DNA binding as well as in functional reporter-gene assays. These results suggest that the two transcription factors are independently regulated and may perform different functions during T-cell activation.

Induction of the POU domain transcription factor Oct-2 during T-cell activation by cognate antigen

1992 ◽  
Vol 12 (7) ◽  
pp. 3149-3154
Author(s):  
S M Kang ◽  
W Tsang ◽  
S Doll ◽  
P Scherle ◽  
H S Ko ◽  
...  
Keyword(s):  
T Cells ◽  
Transcription Factor ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Interleukin 2 ◽  
Cell Lineage ◽  
Antigen Stimulation ◽  
Mrna Induction ◽  
T Cell Clone

Oct-2 is a transcription factor that binds specifically to octamer DNA motifs in the promoters of immunoglobulin and interleukin-2 genes. All tumor cell lines from the B-cell lineage and a few from the T-cell lineage express Oct-2. To address the role of Oct-2 in the T-cell lineage, we studied the expression of Oct-2 mRNA and protein in nontransformed human and mouse T cells. Oct-2 was found in CD4+ and CD8+ T cells prepared from human peripheral blood and in mouse lymph node T cells. In a T-cell clone specific for pigeon cytochrome c in the context of I-Ek, Oct-2 was induced by antigen stimulation, with the increase in Oct-2 protein seen first at 3 h after activation and continuing for at least 24 h. Oct-2 mRNA induction during antigen-driven T-cell activation was blocked by cyclosporin A, as well as by protein synthesis inhibitors. These results suggest that Oct-2 participates in transcriptional regulation during T-cell activation. The relatively delayed kinetics of Oct-2 induction suggests that Oct-2 mediates the changes in gene expression which occur many hours or days following antigen stimulation of T lymphocytes.

scholarly journals Induction of the POU domain transcription factor Oct-2 during T-cell activation by cognate antigen.

1992 ◽  
Vol 12 (7) ◽  
pp. 3149-3154 ◽  
Author(s):  
S M Kang ◽  
W Tsang ◽  
S Doll ◽  
P Scherle ◽  
H S Ko ◽  
...  
Keyword(s):  
T Cells ◽  
Transcription Factor ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Interleukin 2 ◽  
Cell Lineage ◽  
Antigen Stimulation ◽  
Mrna Induction ◽  
T Cell Clone

Oct-2 is a transcription factor that binds specifically to octamer DNA motifs in the promoters of immunoglobulin and interleukin-2 genes. All tumor cell lines from the B-cell lineage and a few from the T-cell lineage express Oct-2. To address the role of Oct-2 in the T-cell lineage, we studied the expression of Oct-2 mRNA and protein in nontransformed human and mouse T cells. Oct-2 was found in CD4+ and CD8+ T cells prepared from human peripheral blood and in mouse lymph node T cells. In a T-cell clone specific for pigeon cytochrome c in the context of I-Ek, Oct-2 was induced by antigen stimulation, with the increase in Oct-2 protein seen first at 3 h after activation and continuing for at least 24 h. Oct-2 mRNA induction during antigen-driven T-cell activation was blocked by cyclosporin A, as well as by protein synthesis inhibitors. These results suggest that Oct-2 participates in transcriptional regulation during T-cell activation. The relatively delayed kinetics of Oct-2 induction suggests that Oct-2 mediates the changes in gene expression which occur many hours or days following antigen stimulation of T lymphocytes.

scholarly journals Inhibition of Antigen-Specific and Nonspecific Stimulation of Bovine T and B Cells by Lymphostatin from Attaching and Effacing Escherichia coli

2016 ◽  
Vol 85 (2) ◽  
Author(s):  
Robin L. Cassady-Cain ◽  
Elizabeth A. Blackburn ◽  
Charlotte R. Bell ◽  
Elizaveta Elshina ◽  
Jayne C. Hope ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
T Cells ◽  
T Cell ◽  
B Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Interleukin 2 ◽  
Content Type ◽  
E Coli ◽  
Stimulation Of

ABSTRACT Enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) are enteric bacterial pathogens of worldwide importance. Most EPEC and non-O157 EHEC strains express lymphostatin (also known as LifA), a chromosomally encoded 365-kDa protein. We previously demonstrated that lymphostatin is a putative glycosyltransferase that is important in intestinal colonization of cattle by EHEC serogroup O5, O111, and O26 strains. However, the nature and consequences of the interaction between lymphostatin and immune cells from the bovine host are ill defined. Using purified recombinant protein, we demonstrated that lymphostatin inhibits mitogen-activated proliferation of bovine T cells and, to a lesser extent, proliferation of cytokine-stimulated B cells, but not NK cells. It broadly affected the T cell compartment, inhibiting all cell subsets (CD4, CD8, WC-1, and γδ T cell receptor [γδ-TCR]) and cytokines examined (interleukin 2 [IL-2], IL-4, IL-10, IL-17A, and gamma interferon [IFN-γ]) and rendered T cells refractory to mitogen for a least 18 h after transient exposure. Lymphostatin was also able to inhibit proliferation of T cells stimulated by IL-2 and by antigen presentation using a Theileria-transformed cell line and autologous T cells from Theileria-infected cattle. We conclude that lymphostatin is likely to act early in T cell activation, as stimulation of T cells with concanavalin A, but not phorbol 12-myristate 13-acetate combined with ionomycin, was inhibited. Finally, a homologue of lymphostatin from E. coli O157:H7 (ToxB; L7095) was also found to possess comparable inhibitory activity against T cells, indicating a potentially conserved strategy for interference in adaptive responses by attaching and effacing E. coli.

scholarly journals Blockade of T-cell activation by dithiocarbamates involves novel mechanisms of inhibition of nuclear factor of activated T cells.

1997 ◽  
Vol 17 (11) ◽  
pp. 6437-6447 ◽  
Author(s):  
S Martínez-Martínez ◽  
P Gómez del Arco ◽  
A L Armesilla ◽  
J Aramburu ◽  
C Luo ◽  
...  
Keyword(s):  
T Cells ◽  
Transcription Factor ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Regulation Of Gene Expression ◽  
Interleukin 2 ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Nf Kappab

Dithiocarbamates (DTCs) have recently been reported as powerful inhibitors of NF-kappaB activation in a number of cell types. Given the role of this transcription factor in the regulation of gene expression in the inflammatory response, NF-kappaB inhibitors have been suggested as potential therapeutic drugs for inflammatory diseases. We show here that DTCs inhibited both interleukin 2 (IL-2) synthesis and membrane expression of antigens which are induced during T-cell activation. This inhibition, which occurred with a parallel activation of c-Jun transactivating functions and expression, was reflected by transfection experiments at the IL-2 promoter level, and involved not only the inhibition of NF-kappaB-driven reporter activation but also that of nuclear factor of activated T cells (NFAT). Accordingly, electrophoretic mobility shift assays (EMSAs) indicated that pyrrolidine DTC (PDTC) prevented NF-kappaB, and NFAT DNA-binding activity in T cells stimulated with either phorbol myristate acetate plus ionophore or antibodies against the CD3-T-cell receptor complex and simultaneously activated the binding of AP-1. Furthermore, PDTC differentially targeted both NFATp and NFATc family members, inhibiting the transactivation functions of NFATp and mRNA induction of NFATc. Strikingly, Western blotting and immunocytochemical experiments indicated that PDTC promoted a transient and rapid shuttling of NFATp and NFATc, leading to their accelerated export from the nucleus of activated T cells. We propose that the activation of an NFAT kinase by PDTC could be responsible for the rapid shuttling of the NFAT, therefore transiently converting the sustained transactivation of this transcription factor that occurs during lymphocyte activation, and show that c-Jun NH2-terminal kinase (JNK) can act by directly phosphorylating NFATp. In addition, the combined inhibitory effects on NFAT and NF-KB support a potential use of DTCs as immunosuppressants.

scholarly journals DNA-PKcs kinase activity stabilizes the transcription factor Egr1 in activated immune cells

2021 ◽  
Author(s):  
Zachary J Waldrip ◽  
Lyle Burdine ◽  
David K Harrison ◽  
Ana Clara Azevedo-Pouly ◽  
Aaron J Storey ◽  
...  
Keyword(s):  
T Cells ◽  
Transcription Factor ◽  
T Cell ◽  
Cell Fate ◽  
T Cell Activation ◽  
Immune Cells ◽  
Cell Activation ◽  
Interleukin 2 ◽  
T Cell Response ◽  
Activated T Cells

DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is known primarily for its function in DNA double-stranded break repair and non-homologous end joining (NHEJ). However, like other DNA damage repair kinases (DDR), DNA-PKcs also has a critical yet undefined role in immunity impacting both myeloid and lymphoid cell lineages spurring interest in targeting DNA-PKcs for therapeutic strategies in immune-related diseases. To gain insight into the function of DNA-PKcs within immune cells, we performed a quantitative phosphoproteomic screen in T cells to identify first order phosphorylation targets of DNA-PKcs. Results indicate that DNA-PKcs phosphorylates the transcription factor Egr1 (early growth response protein 1) at S301. Expression of Egr1 is induced early upon T cell activation and dictates T cell response by modulating expression of cytokines and key costimulatory molecules. Mutation of serine 301 to alanine via CRISPR-Cas9 resulted in increased proteasomal degradation of Egr1 and a decrease in Egr1-dependent transcription of IL2 (interleukin-2) in activated T cells. Our findings identify DNA-PKcs as a critical intermediary link between T cell activation and T cell fate and a novel phosphosite involved in regulating Egr1 activity.

scholarly journals CD28-B7 interactions allow the induction of CD8+ cytotoxic T lymphocytes in the absence of exogenous help.

1993 ◽  
Vol 177 (6) ◽  
pp. 1791-1796 ◽  
Author(s):  
F A Harding ◽  
J P Allison
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cytotoxic T Cells ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Histocompatibility Complex ◽  
Necessary And Sufficient ◽  
Additional Antigen

The activation requirements for the generation of CD8+ cytotoxic T cells (CTL) are poorly understood. Here we demonstrate that in the absence of exogenous help, a CD28-B7 interaction is necessary and sufficient for generation of class I major histocompatibility complex-specific CTL. Costimulation is required only during the inductive phase of the response, and not during the effector phase. Transfection of the CD28 counter receptor, B7, into nonstimulatory P815 cells confers the ability to elicit P815-specific CTL, and this response can be inhibited by anti-CD28 Fab or by the chimeric B7-binding protein CTLA4Ig. Anti-CD28 monoclonal antibody (mAb) can provide a costimulatory signal to CD8+ T cells when the costimulatory capacity of splenic stimulators is destroyed by chemical fixation. CD28-mediated signaling provokes the release of interleukin 2 (IL-2) from the CD8+ CTL precursors, as anti-CD28 mAb could be substituted for by the addition of IL-2, and an anti-IL-2 mAb can block the generation of anti-CD28-induced CTL. CD4+ cells are not involved in the costimulatory response in the systems examined. We conclude that CD8+ T cell activation requires two signals: an antigen-specific signal mediated by the T cell receptor, and an additional antigen nonspecific signal provided via a CD28-B7 interaction.

scholarly journals NF-kappa B as inducible transcriptional activator of the granulocyte-macrophage colony-stimulating factor gene.

1990 ◽  
Vol 10 (3) ◽  
pp. 1281-1286 ◽  
Author(s):  
R Schreck ◽  
P A Baeuerle
Keyword(s):  
T Cells ◽  
Transcription Factor ◽  
T Cell ◽  
Interleukin 2 ◽  
Colony Stimulating Factor ◽  
Nf Kappa B ◽  
Gm Csf ◽  
Macrophage Colony Stimulating Factor ◽  
Macrophage Colony ◽  
Stimulating Factor

The expression of the gene encoding the granulocyte-macrophage colony-stimulating factor (GM-CSF) is induced upon activation of T cells with phytohemagglutinin and active phorbolester and upon expression of tax1, a transactivating protein of the human T-cell leukemia virus type I. The same agents induce transcription from the interleukin-2 receptor alpha-chain and interleukin-2 genes, depending on promoter elements that bind the inducible transcription factor NF-kappa B (or an NF-kappa B-like factor). We therefore tested the possibility that the GM-CSF gene is also regulated by a cognate motif for the NF-kappa B transcription factor. A recent functional analysis by Miyatake et al. (S. Miyatake, M. Seiki, M. Yoshida, and K. Arai, Mol. Cell. Biol. 8:5581-5587, 1988) described a short promoter region in the GM-CSF gene that conferred strong inducibility by T-cell-activating signals and tax1, but no NF-kappa B-binding motifs were identified. Using electrophoretic mobility shift assays, we showed binding of purified human NF-kappa B and of the NF-kappa B activated in Jurkat T cells to an oligonucleotide comprising the GM-CSF promoter element responsible for mediating responsiveness to T-cell-activating signals and tax1. As shown by a methylation interference analysis and oligonucleotide competition experiments, purified NF-kappa B binds at positions -82 to -91 (GGGAACTACC) of the GM-CSF promoter sequence with an affinity similar to that with which it binds to the biologically functional kappa B motif in the beta interferon promoter (GGGAAATTCC). Two kappa B-like motifs at positions -98 to -108 of the GM-CSF promoter were also recognized but with much lower affinities. Our data provide strong evidence that the expression of the GM-CSF gene following T-cell activation is controlled by binding of the NF-kappa B transcription factor to a high-affinity binding site in the GM-CSF promoter.

scholarly journals SLFN2 protection of tRNAs from stress-induced cleavage is essential for T cell–mediated immunity

Science ◽  
2021 ◽  
Vol 372 (6543) ◽  
pp. eaba4220 ◽  
Author(s):  
Tao Yue ◽  
Xiaoming Zhan ◽  
Duanwu Zhang ◽  
Ruchi Jain ◽  
Kuan-wen Wang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Cell Mediated Immunity ◽  
Activated T Cells ◽  
Granule Formation

Reactive oxygen species (ROS) increase in activated T cells because of metabolic activity induced to support T cell proliferation and differentiation. We show that these ROS trigger an oxidative stress response that leads to translation repression. This response is countered by Schlafen 2 (SLFN2), which directly binds transfer RNAs (tRNAs) to protect them from cleavage by the ribonuclease angiogenin. T cell–specific SLFN2 deficiency results in the accumulation of tRNA fragments, which inhibit translation and promote stress-granule formation. Interleukin-2 receptor β (IL-2Rβ) and IL-2Rγ fail to be translationally up-regulated after T cell receptor stimulation, rendering SLFN2-deficient T cells insensitive to interleukin-2’s mitogenic effects. SLFN2 confers resistance against the ROS-mediated translation-inhibitory effects of oxidative stress normally induced by T cell activation, permitting the robust protein synthesis necessary for T cell expansion and immunity.

scholarly journals Antigen-independent activation of naive and memory resting T cells by a cytokine combination.

1994 ◽  
Vol 180 (3) ◽  
pp. 1159-1164 ◽  
Author(s):  
D Unutmaz ◽  
P Pileri ◽  
S Abrignani
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Interleukin 2 ◽  
Effector Function ◽  
Necrosis Factor Alpha ◽  
Naive T Cells ◽  
Naïve T Cells

We investigated whether human resting T cells could be activated to proliferate and display effector function in the absence of T cell receptor occupancy. We report that combination of interleukin 2 (IL-2), tumor necrosis factor alpha, and IL-6 activated highly purified naive (CD45RA+) and memory (CD45RO+) resting CD4+ T cells to proliferate. Under this condition, memory resting T cells could also display effector function as measured by lymphokine synthesis and help for immunoglobulin production by B cells. This novel Ag-independent pathway of T cell activation may play an important role in vivo in recruiting effector T cells at the site of immune response and in maintaining the clonal size of memory T cells in the absence of antigenic stimulation. Moreover, cytokines can induce proliferation of naive T cells without switch to memory phenotype and this may help the maintenance of the peripheral pool of naive T cells.

Effect of CD28 signal transduction on c-Rel in human peripheral blood T cells

1994 ◽  
Vol 14 (12) ◽  
pp. 7933-7942
Author(s):  
R G Bryan ◽  
Y Li ◽  
J H Lai ◽  
M Van ◽  
N R Rice ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Peripheral Blood ◽  
Cell Activation ◽  
Nuclear Translocation ◽  
Human Peripheral Blood ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Cd28 Costimulation

Optimal T-cell activation requires both an antigen-specific signal delivered through the T-cell receptor and a costimulatory signal which can be delivered through the CD28 molecule. CD28 costimulation induces the expression of multiple lymphokines, including interleukin 2 (IL-2). Because the c-Rel transcription factor bound to and activated the CD28 response element within the IL-2 promoter, we focused our study on the mechanism of CD28-mediated regulation of c-Rel in human peripheral blood T cells. We showed that CD28 costimulation accelerated the kinetics of nuclear translocation of c-Rel (and its phosphorylated form), p50 (NFKB1), and p65 (RelA). The enhanced nuclear translocation of c-Rel correlated with the stimulation of Il-2 production and T-cell proliferation by several distinct anti-CD28 monoclonal antibodies. This is explained at least in part by the long-term downregulation of I kappa B alpha following CD28 signalling as opposed to phorbol myristate acetate alone. Furthermore, we showed that the c-Rel-containing CD28-responsive complex is enhanced by, but not specific to, CD28 costimulation. Our results indicate that c-Rel is one of the transcription factors targeted by CD28 signalling.

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