scholarly journals Discrete Generation of Superoxide and Hydrogen Peroxide by T Cell Receptor Stimulation

2002 ◽  
Vol 195 (1) ◽  
pp. 59-70 ◽  
Author(s):  
Satish Devadas ◽  
Luba Zaritskaya ◽  
Sue Goo Rhee ◽  
Larry Oberley ◽  
Mark S. Williams
Keyword(s):  
Hydrogen Peroxide ◽  
T Cell ◽  
T Cell Receptor ◽  
Superoxide Anion ◽  
Fas Ligand ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Activated T Cells ◽  
Tcr Signals ◽  
Hydrogen Peroxide Generation

Receptor-stimulated generation of reactive oxygen species (ROS) has been shown to regulate signal transduction, and previous studies have suggested that T cell receptor (TCR) signals may involve or be sensitive to ROS. In this study, we have shown for the first time that TCR cross-linking induced rapid (within 15 min) generation of both hydrogen peroxide and superoxide anion, as defined with oxidation-sensitive dyes, selective pharmacologic antioxidants, and overexpression of specific antioxidant enzymes. Furthermore, the data suggest the novel observation that superoxide anion and hydrogen peroxide are produced separately by distinct TCR-stimulated pathways. Unexpectedly, TCR-stimulated activation of the Fas ligand (FasL) promoter and subsequent cell death was dependent upon superoxide anion, but independent of hydrogen peroxide, while nuclear factor of activated T cells (NFAT) activation or interleukin 2 transcription was independent of all ROS. Anti-CD3 induced phosphorylation of extracellular signal–regulated kinase (ERK)1/2 required hydrogen peroxide generation but was unaffected by superoxide anion. Thus, antigen receptor signaling induces generation of discrete species of oxidants that selectively regulate two distinct redox sensitive pathways, a proapoptotic (FasL) and a proliferative pathway (ERK).

scholarly journals Distinct T cell receptor signaling requirements for perforin- or FasL-mediated cytotoxicity.

1996 ◽  
Vol 183 (4) ◽  
pp. 1697-1706 ◽  
Author(s):  
M T Esser ◽  
B Krishnamurthy ◽  
V L Braciale
Keyword(s):  
Signal Transduction ◽  
T Cell ◽  
T Cell Receptor ◽  
Fas Ligand ◽  
Cytotoxic T Lymphocyte ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Receptor Expression ◽  
Cell Surface Receptor ◽  
Tcr Signaling

A diverse array of signals are generated in a cytotoxic T lymphocyte (CTL) after the T cell receptor (TCR) engages the class I major histocompatibility complex (MHC) peptide complex. These signals result in a multitude of CTL effector functions, including cellular cytotoxicity, cell surface receptor expression, and cytokine secretion. We have examined signaling through the TCR in a wild type CD8+, MHC-restricted, antigen-specific CTL clone, 14-7, and its interleukin 2-dependent variant clone 14-7FD. We report here that 14-7FD is unable to kill via the perforin mechanism of killing, yet is able to kill via the Fas ligand/Fas mechanism and secrete interferon-gamma in an antigen-specific manner. 14-7FD has cytolytic granules that contain perforin and serine esterases, which are secreted after phorbol ester and Ca2+ ionophore treatment. Lastly, to investigate which TCR signaling requirements were operational in 14-7FD, we examined TCR-triggered intracellular Ca2+ mobilization in the two clones. After TCR engagement, 14-7FD failed to mobilize intracellular Ca2+, which may be the cause for its inability to trigger the perforin/granule exocytosis mechanism of killing. These results indicate that the signal transduction events that trigger perforin killing and the signaling requirements to induce FasL expression are distinct. We hypothesize that these two distinct TCR signal transduction requirements allow for separate activation of these two mechanisms of killing relating to their role in eradication of infected cells or regulation of immune responses.

scholarly journals Novel NFAT sites that mediate activation of the interleukin-2 promoter in response to T-cell receptor stimulation.

1995 ◽  
Vol 15 (11) ◽  
pp. 6299-6310 ◽  
Author(s):  
J W Rooney ◽  
Y L Sun ◽  
L H Glimcher ◽  
T Hoey
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Receptor Stimulation ◽  
Activated T Cells ◽  
Diverse Range ◽  
Dnase I Footprinting ◽  
Responsive Element ◽  
Insight Into

The transcription factors NFAT and AP-1 have been shown to be essential for inducible interleukin-2 (IL-2) expression in activated T cells. NFAT has been previously reported to bind to two sites in the IL-2 promoter: in association with AP-1 at the distal antigen response element at -280 and at -135. On the basis of DNase I footprinting with recombinant NFAT and AP-1 proteins, gel shift assays, and transfection experiments, we have identified three additional NFAT sites in the IL-2 promoter. Strikingly, all five NFAT sites are essential for the full induction of promoter activity in response to T-cell receptor stimulation. Four of the five NFAT sites are part of composite elements able to bind AP-1 in association with NFAT. These sites display a diverse range of cooperativity and interdependency on NFAT and AP-1 proteins for binding. One of the NFAT sites directly overlaps the CD28-responsive element. We present evidence that CD28 inducibility is conferred by the AP-1 component in NFAT-AP-1 composite elements. These findings provide further insight into the mechanisms involved in the regulation of the IL-2 promoter.

scholarly journals Normal Regulatory α/β T Cells Effectively Eliminate Abnormally Activated T Cells Lacking the Interleukin 2 Receptor β in Vivo

1999 ◽  
Vol 190 (11) ◽  
pp. 1561-1572 ◽  
Author(s):  
Haruhiko Suzuki ◽  
Yan Wen Zhou ◽  
Masashi Kato ◽  
Tak W. Mak ◽  
Izumi Nakashima
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Fas Ligand ◽  
Bone Marrow Cells ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Activated T Cells ◽  
Receptor System

Although interleukin 2 (IL-2) has been thought to be the most important cytokine for T cell growth, animals lacking IL-2 or a component of its receptor molecules have more expanded T cells with activated memory phenotype, indicating an indispensable role for the IL-2/IL-2 receptor system in regulating the size and activity of the T cell population. In this study, we investigated the possible mechanism of abnormal expansion of activated T cells in IL-2 receptor β chain (IL-2Rβ)−/− mice using the systems of bone marrow transplantation and T cell transfer. Here, we show that IL-2Rβ2/− T cells in mice reconstituted with a mixture of IL-2Rβ2/− and IL-2Rβ1/+ bone marrow cells did not develop into an abnormally activated stage, and that already activated IL-2Rβ2/− T cells were effectively eliminated by IL-2Rβ1/+ T cells when both cells were cotransferred to T cell–deficient host mice. This regulation and/or elimination was dependent on T cells bearing α/β type T cell receptor, especially on CD8+ T cells and independent of the Fas–Fas ligand (FasL) system. IL-2Rβ1/+ T cells that eliminated activated IL-2Rβ2/− T cells expressed FasL, perforin, granzyme B, and tumor necrosis factor α/β. These results indicate a novel function of IL-2Rβ that is necessary for the induction of regulatory T cells acting to eliminate activated T cells.

scholarly journals RasGRF2, a Guanosine Nucleotide Exchange Factor for Ras GTPases, Participates in T-Cell Signaling Responses

2007 ◽  
Vol 27 (23) ◽  
pp. 8127-8142 ◽  
Author(s):  
Sergio Ruiz ◽  
Eugenio Santos ◽  
Xosé R. Bustelo
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Signaling ◽  
Phospholipase C ◽  
T Cell Receptor ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
T Cell Signaling ◽  
Activated T Cells ◽  
Exchange Factor

ABSTRACT The Ras pathway is critical for the development and function of T lymphocytes. The stimulation of this GTPase in T cells occurs primarily through the Vav1- and phospholipase C-γ1-dependent activation of RasGRP1, a diacylglycerol-responsive Ras GDP/GTP exchange factor. Here, we show that a second exchange factor, RasGRF2, also participates in T-cell signaling. RasGRF2 is expressed in T cells, translocates to immune synapses, activates Ras, and stimulates the transcriptional factor NF-AT (nuclear factor of activated T cells) through Ras- and phospholipase C-γ1-dependent routes. T-cell receptor-, Vav1-, and Ca2+-elicited pathways synergize with RasGRF2 for NF-AT stimulation. The analysis of RasGRF2-deficient mice indicates that this protein is required for the induction of bona fide NF-AT targets such as the cytokines tumor necrosis factor alpha and interleukin 2, while it plays minor roles in Ras activation itself. The comparison of lymphocytes from Vav1 −/−, Rasgrf2 −/−, and Vav1 −/−; Rasgrf2 −/− mice demonstrates that the RasGRF2 pathway cooperates with the Vav1/RasGRP1 route in the blasting transformation and proliferation of mature T cells. These results identify RasGRF2 as an additional component of the signaling machinery involved in T-cell receptor- and NF-AT-mediated immune responses.

scholarly journals T cell receptor-dependent cell death of T cell hybridomas mediated by the CD30 cytoplasmic domain in association with tumor necrosis factor receptor-associated factors.

1996 ◽  
Vol 183 (2) ◽  
pp. 669-674 ◽  
Author(s):  
S Y Lee ◽  
C G Park ◽  
Y Choi
Keyword(s):  
Cell Death ◽  
T Cell ◽  
Tumor Necrosis Factor ◽  
T Cell Receptor ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Receptor ◽  
Cell Receptor ◽  
Cytoplasmic Domain ◽  
Activated T Cells ◽  
Necrosis Factor

CD30 is a member of the tumor necrosis factor superfamily and a surface marker for Hodgkin's disease. Normal activated T cells and several virally transformed T or B cell lines also show CD30 expression. The interaction of CD30 with its ligand induces cell death or proliferation, depending on the cell type. In this report we characterize the signals mediated by the intracellular domain of CD30 and show that, in combination with signal(s) transduced by the T cell receptor, the multimerization of CD30 cytoplasmic domain induces Fas(CD95)-independent cell death in T cell hybridomas. Deletion analysis shows that the COOH-terminal 66 amino acids of CD30 are required to induce cell death. Using the yeast two-hybrid system, we have identified that the same region of CD30 interacts with tumor necrosis factor receptor-associated factor (TRAF)1 and TRAF2. These results indicate that TRAF1 and/or TRAF2 play an important role in cell death in addition to their previously identified roles in cell proliferation.

Ig alpha and Ig beta are functionally homologous to the signaling proteins of the T-cell receptor

1994 ◽  
Vol 14 (2) ◽  
pp. 1095-1103
Author(s):  
A L Burkhardt ◽  
T Costa ◽  
Z Misulovin ◽  
B Stealy ◽  
J B Bolen ◽  
...  
Keyword(s):  
Signal Transduction ◽  
T Cells ◽  
T Cell ◽  
B Cell ◽  
T Cell Receptor ◽  
Interleukin 2 ◽  
Antigen Receptor ◽  
Cell Receptor ◽  
Antigen Receptors ◽  
Cell Antigen

Signal transduction by antigen receptors and some Fc receptors requires the activation of a family of receptor-associated transmembrane accessory proteins. One common feature of the cytoplasmic domains of these accessory molecules is the presence is at least two YXXA repeats that are potential sites for interaction with Src homology 2 domain-containing proteins. However, the degree of similarity between the different receptor-associated proteins varies from that of T-cell receptor (TCR) zeta and Fc receptor RIIIA gamma chains, which are homologous, to the distantly related Ig alpha and Ig beta proteins of the B-cell antigen receptor. To determine whether T- and B-cell antigen receptors are in fact functionally homologous, we have studied signal transduction by chimeric immunoglobulins bearing the Ig alpha or Ig beta cytoplasmic domain. We found that Ig alpha and Ig beta cytoplasmic domains were able to activate Ca2+ flux, interleukin-2 secretion, and phosphorylation of the same group of cellular substrates as the TCR in transfected T cells. Chimeric proteins were then used to examine the minimal requirements for activation of the Fyn, Lck, and ZAP kinases in T cells. Both Ig alpha and Ig beta were able to trigger Fyn, Lck, and ZAP directly without involvement of TCR components. Cytoplasmic tyrosine residues in Ig beta were required for recruitment and activation of ZAP-70, but these amino acids were not essential for the activation of Fyn and Lck. We conclude that Fyn and Lck are able to recognize a clustered nonphosphorylated immune recognition receptor, but activation of these kinases is not sufficient to induce cellular responses such as Ca2+ flux and interleukin-2 secretion. In addition, the molecular structures involved in antigen receptor signaling pathways are conserved between T and B cells.

T-cell proliferation involving the CD28 pathway is associated with cyclosporine-resistant interleukin 2 gene expression

1987 ◽  
Vol 7 (12) ◽  
pp. 4472-4481
Author(s):  
C H June ◽  
J A Ledbetter ◽  
M M Gillespie ◽  
T Lindsten ◽  
C B Thompson
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
T Cell Proliferation ◽  
Cd28 Molecule ◽  
T Cell Stimulation ◽  
Protein Kinase C Activation

CD28 is a homodimeric glycoprotein expressed on the surface of a major subset of human T cells that has recently been identified as a member of the immunoglobulin supergene family. The binding of monoclonal antibodies to the CD28 antigen on purified T cells does not result in proliferation; however, previous studies have shown that the combination of CD28 stimulation and protein kinase C activation by phorbol myristate acetate (PMA) results in T-cell proliferation that is independent of both accessory cells and activation of the T-cell receptor-CD3 complex. In the present study, effects of stimulation by anti-CD28 on cell cycle progression and on the interleukin 2 (IL-2) and IL-2 receptor system have been investigated on primary cultures of purified peripheral-blood CD28+ T cells. There was no measurable effect on cell size or on DNA synthesis after stimulation of resting (G0) cells by CD28 alone. After 3 h of activation of T cells by PMA alone, a slight (8%) increase in cell volume occurred that did not progress to DNA synthesis. In contrast, T-cell stimulation by CD28 in combination with PMA resulted in a progressive increase in cell volume in approximately 100% of cells at 12 to 14 h after stimulation. Northern blot (RNA blot) analysis revealed that CD28 stimulation alone failed to cause expression of the alpha chain of the IL-2 receptor or of IL-2 mRNA, and in accord with previous studies, stimulation by PMA alone resulted in the accumulation of IL-2 receptor transcripts but no detectable IL-2 mRNA. In contrast, T-cell stimulation by the combination of CD28 and PMA resulted in the appearance of IL-2 transcripts and enhanced expression of IL-2 receptor mRNA. Functional studies revealed that the proliferation induced by CD28 and PMA stimulation was entirely resistant to cyclosporine, in contrast to T-cell activation induced by the CD3-T-cell receptor complex. Cyclosporine was found not to affect the accumulation of IL-2 mRNA after CD28 plus PMA stimulation, although there was no detectable IL-2 mRNA after stimulation by CD3 in the presence of the drug. Furthermore, stimulation by CD28 in combination with immobilized CD3 antibodies caused a striking enhancement of IL-2 mRNA expression that was, in part, resistant to the effects of cyclosporine. These studies indicate that the CD28 molecule synergizes with protein kinase C activation to induce IL-2 gene expression and demonstrate that stimulation by the CD28 pathway can cause vigorous T-cell proliferation even in the presence of cyclosporine and that cyclosporine does not prevent transcription of 16-2 mRNA, as has been suggested previously. Moreover, these findings suggest that a potential role for the CD28 molecule in vivo may be to augment IL-2 production after stimulation of the CD3-T-cell receptor molecular complex and thereby to amplify an antigen-specific immune response. Finally, these results provide further evidence that the CD28 molecule triggers T-cell proliferation in a manner that differs biochemically from CD3-T-cell receptor-induced proliferation.

scholarly journals Evidence for extrathymic generation of intermediate T cell receptor cells in the liver revealed in thymectomized, irradiated mice subjected to bone marrow transplantation.

1995 ◽  
Vol 182 (3) ◽  
pp. 759-767 ◽  
Author(s):  
K Sato ◽  
K Ohtsuka ◽  
K Hasegawa ◽  
S Yamagiwa ◽  
H Watanabe ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Bone Marrow Transplantation ◽  
T Cell ◽  
T Cell Receptor ◽  
Marrow Transplantation ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Phenotypic Characterization ◽  
Receptor Cells

In addition to the major intrathymic pathway of T cell differentiation, extrathymic pathways of such differentiation have been shown to exist in the liver and intestine. In particular, hepatic T cells of T cell receptors or CD3 of intermediate levels (i.e., intermediate T cell receptor cells) always contain self-reactive clones and sometimes appear at other sites, including the target tissues in autoimmune diseases and the tumor sites in malignancies. To prove their extrathymic origin and self reactivity, in this study we used thymectomized, irradiated (B6 x C3H/He) F1 mice subjected to transplantation of bone marrow cells of B6 mice. It was clearly demonstrated that all T cells generated under athymic conditions in the peripheral immune organs are intermediate CD3 cells. In the case of nonthymectomized irradiated mice, not only intermediate CD3 cells but also high CD3 cells were generated. Phenotypic characterization showed that newly generated intermediate CD3 cells were unique (e.g., interleukin 2 receptor alpha-/beta+ and CD44+ L-selectin-) and were, therefore, distinguishable from thymus-derived T cells. The precursor cells of intermediate CD3 cells in the bone marrow were Thy-1+ CD3-. The extrathymic generation of intermediate CD3 cells was confirmed in other combinations of bone marrow transplantation, C3H --> C3H and B10.Thy1.1 --> B6.Thy1.2. The generated intermediate CD3 cells in the liver contained high levels of self-reactive clones estimated by anti-V beta monoclonal antibodies in conjunction with the endogenous superantigen minor lymphocyte-stimulating system, especially the combination of B6 --> (B6 x C3H/He) (graft-versus-host-situation).(ABSTRACT TRUNCATED AT 250 WORDS)

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