An antigen receptor-driven, interleukin 2-independent pathway for proliferation of murine cytolytic T lymphocyte clones.

Proliferation of T lymphocytes can be induced by IL-2, either through an autocrine pathway in which the responding cell produces its own IL-2 or through an exocrine pathway in which IL-2 secreted by Th stimulates proliferation of IL-2-dependent CTL. However, proliferation of at least some CTL clones, such as CTL L3 and CTL dB45, also can be induced by stimulation of the antigen receptor in the absence of IL-2. Stimulation of these cloned CTL with T cell-depleted allogeneic spleen cells, allogeneic tumor cells, or immobilized mAb reactive with the T cell antigen receptor (TCR) induced thymidine incorporation, entry into cell cycle, and secretion of macrophage activating factor, but these stimuli did not induce the secretion of IL-2. Several observations indicated that such proliferation of cloned CTL induced by stimulation of the TCR was independent of IL-2; IL-2 could not be detected in supernatants from stimulated CTL cells. mAbs reactive with the murine IL-2-R efficiently blocked IL-2-mediated thymidine incorporation in cloned CTL and Th, but had no inhibitory effect on TCR-driven thymidine incorporation in the CTL clones. TCR-driven thymidine incorporation in cloned Th L2 cells was profoundly inhibited by these antibodies, indicating the operation of an IL-2-mediated autocrine pathway for proliferation in this cloned Th. When antibodies to the TCR were used to stimulate cloned CTL and Th, IFN-gamma mRNA was easily shown in the cloned CTL and Th. Although IL-2 mRNA could be detected in the cloned Th, it was never observed in the cloned CTL. These findings provide evidence for the existence of a TCR-mediated, IL-2-independent pathway for induction of cellular proliferation in cloned murine CTL.

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Insulin-modulated interleukin-2 production by murine splenocytes and a T-cell hybridoma

Journal of Endocrinology ◽

10.1677/joe.0.1140089 ◽

1987 ◽

Vol 114 (1) ◽

pp. 89-94 ◽

Cited By ~ 2

Author(s):

K. Pavelić ◽

R. J. Bernacki ◽

S. Vuk-Pavlović

Keyword(s):

T Cell ◽

Thymidine Incorporation ◽

Interleukin 2 ◽

Growth Stimulation ◽

Hybridoma Cells ◽

Con A ◽

Murine Splenocytes ◽

Serum Free ◽

Free Media ◽

Stimulation Of

ABSTRACT Murine interleukin-2 (IL-2)-producing AOFS 21 T-cell hybridoma cells and normal murine splenocytes were stimulated in serum-free media by 16 potential mitogens/growth factors. Only insulin, concanavalin A (Con A), peptidoglycan monomer and a tumour-derived insulinoid stimulated [3H]thymidine incorporation by AOFS 21 cells and splenocytes. Supernatants of these stimulated cultures were tested for IL-2 activity which generally followed the pattern of growth stimulation. Both the mitogenicity and stimulation of IL-2 secretion by insulin were second only to the effects of Con A. J. Endocr. (1987) 114, 89–94

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Concanavalin A-inducible, interleukin-2-producing T cell hybridoma.

Journal of Experimental Medicine ◽

10.1084/jem.152.4.893 ◽

1980 ◽

Vol 152 (4) ◽

pp. 893-904 ◽

Cited By ~ 91

Author(s):

L Harwell ◽

B Skidmore ◽

P Marrack ◽

J Kappler

Keyword(s):

T Cells ◽

T Cell ◽

Concanavalin A ◽

Interleukin 2 ◽

Hybridoma Cells ◽

Adherent Cell ◽

Spleen Cells ◽

Con A ◽

Normal Spleen ◽

Stimulation Of

The fusion of an AKR T cell tumor line to normal B6D2F1, T cells resulted in the production of a cloned T cell hybridoma (FS6-14.13) inducible with the mitogen concanavalin A (Con A). The supernate from Con A-stimulated hybridoma cells was active both in the stimulation of an anti-sheep red blood cell response by partially T cell-depleted B cells and in the stimulation of the growth of antigen-specific T cell blasts. The active principle in both assays had a molecular weight of approximately 30-40,000. These results indicated the presence of interleukin 2 (IL2) in the hybridoma supernate. The activity of the hybridoma supernate in B cell responses was dependent on the presence of adherent cells and a few contaminating T cells. On the other hand, Con A-stimulated supernates from normal spleen cells were active after either adherent cell removal or severe T cell depletion. These results suggested that IL2 was the only active helper factor in the hybridoma supernate, but that additional helper factors were present in supernates from Con A-stimulated normal spleen cells.

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Removal of C-Terminal Src Kinase from the Immune Synapse by a New Binding Protein

Molecular and Cellular Biology ◽

10.1128/mcb.25.6.2227-2241.2005 ◽

2005 ◽

Vol 25 (6) ◽

pp. 2227-2241 ◽

Cited By ~ 27

Author(s):

Souad Rahmouni ◽

Torkel Vang ◽

Andres Alonso ◽

Scott Williams ◽

Marianne van Stipdonk ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Interleukin 2 ◽

Antigen Receptor ◽

T Cell Antigen Receptor ◽

Intracellular Location ◽

Immune Synapse ◽

Cell Antigen Receptor ◽

Cell Antigen

ABSTRACT The Csk tyrosine kinase negatively regulates the Src family kinases Lck and Fyn in T cells. Engagement of the T-cell antigen receptor results in a removal of Csk from the lipid raft-associated transmembrane protein PAG/Cbp. Instead, Csk becomes associated with an ∼72-kDa tyrosine-phosphorylated protein, which we identify here as G3BP, a phosphoprotein reported to bind the SH3 domain of Ras GTPase-activating protein. G3BP reduced the ability of Csk to phosphorylate Lck at Y505 by decreasing the amount of Csk in lipid rafts. As a consequence, G3BP augmented T-cell activation as measured by interleukin-2 gene activation. Conversely, elimination of endogenous G3BP by RNA interference increased Lck Y505 phosphorylation and reduced TCR signaling. In antigen-specific T cells, endogenous G3BP moved into a intracellular location adjacent to the immune synapse, but deeper inside the cell, upon antigen recognition. Csk colocalization with G3BP occurred in this “parasynaptic” location. We conclude that G3BP is a new player in T-cell-antigen receptor signaling and acts to reduce the amount of Csk in the immune synapse.

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

Molecular and Cellular Biology ◽

10.1128/mcb.14.2.1095-1103.1994 ◽

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.

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Susceptibility to cell death is a dominant phenotype: triggering of activation-driven T-cell death independent of the T-cell antigen receptor complex

Molecular and Cellular Biology ◽

10.1128/mcb.12.1.379-385.1992 ◽

1992 ◽

Vol 12 (1) ◽

pp. 379-385

Author(s):

G Nickas ◽

J Meyers ◽

L D Hebshi ◽

J D Ashwell ◽

D P Gold ◽

...

Keyword(s):

T Cells ◽

Cell Death ◽

T Cell ◽

Interleukin 2 ◽

Antigen Receptor ◽

Alternative Activation ◽

Receptor Complex ◽

T Cell Antigen Receptor ◽

Cell Antigen Receptor ◽

Cell Antigen

The failure of Thy-1 and Ly-6 to trigger interleukin-2 production in the absence of surface T-cell antigen receptor complex (TCR) expression has been interpreted to suggest that functional signalling via these phosphatidylinositol-linked alternative activation molecules is dependent on the TCR. We find, in contrast, that stimulation of T cells via Thy-1 or Ly-6 in the absence of TCR expression does trigger a biological response, the cell suicide process of activation-driven cell death. Activation-driven cell death is a process of physiological cell death that likely represents the mechanism of negative selection of T cells. The absence of the TCR further reveals that signalling leading to activation-driven cell death and to lymphokine production are distinct and dissociable. In turn, the ability of alternative activation molecules to function in the absence of the TCR raises another issue: why immature T cells, thymomas, and hybrids fail to undergo activation-driven cell death in response to stimulation via Thy-1 and Ly-6. One possibility is that these activation molecules on immature T cells are defective. Alternatively, susceptibility to activation-driven cell death may be developmentally regulated by TCR-independent factors. We have explored these possibilities with somatic cell hybrids between mature and immature T cells, in which Thy-1 and Ly-6 are contributed exclusively by the immature partner. The hybrid cells exhibit sensitivity to activation-driven cell death triggered via Thy-1 and Ly-6. Thus, the Thy-1 and Ly-6 molecules of the immature T cells can function in a permissive environment. Moreover, with regard to susceptibility to Thy-1 and Ly-6 molecules of the immature T cells can function in a permissive environment. Moreover, with regard to susceptibility to Thy-1 and Ly-6 triggering, the mature phenotype of sensitivity to cell death is genetically dominant.

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Immunosuppressive effect of human herpesvirus 6 on T-cell functions: suppression of interleukin-2 synthesis and cell proliferation [published erratum appears in Blood 1995 Jul 1;86(1):418]

Blood ◽

10.1182/blood.v85.5.1263.bloodjournal8551263 ◽

1995 ◽

Vol 85 (5) ◽

pp. 1263-1271 ◽

Cited By ~ 106

Author(s):

L Flamand ◽

J Gosselin ◽

I Stefanescu ◽

D Ablashi ◽

J Menezes

Keyword(s):

T Cells ◽

T Cell ◽

T Lymphocyte ◽

Peripheral Blood ◽

Cellular Proliferation ◽

Interleukin 2 ◽

Human Herpesvirus ◽

Human Herpesvirus 6 ◽

Infected Cells ◽

Herpesvirus 6

Human herpesvirus-6 (HHV-6), the etiologic agent of roseola, is ubiquitous, establishes latency in the host, and can infect a variety of immunocompetent cells, with CD4+ T lymphocytes being the targets in which it replicates most efficiently. The present study was undertaken to learn more about specific immunobiologic effects of HHV-6 infection on T-lymphocyte functions. Our data demonstrate that infection of peripheral blood mononuclear cells (PBMC) by HHV-6 results in suppression of T-lymphocyte functions, as evidenced by reduced interleukin-2 (IL-2) synthesis and cellular proliferation. In fact, HHV- 6-infected PBMC secreted 50% less IL-2 than mock-infected cells after mitogenic stimulation with OKT3 antibody or phytohemmaglutinin (PHA). The inhibition of IL-2 by HHV-6 was also observed in enriched T-cell cultures, suggesting a direct effect of this virus on this cell type. Messenger RNA (mRNA) analysis by reverse-transcriptase polymerase chain reaction (PCR) indicated that HHV-6 diminishes IL-2 mRNA levels in mitogen-stimulated peripheral blood T cells. These results were also confirmed by Northern blot using the leukemic T-cell line Jurkat. This inhibitory effect of HHV-6 did not require infectious virus, as the use of UV-irradiated HHV-6 produced similar results. Moreover, HHV-6- infected PBMC showed up to an 85% reduction in their mitogen-driven proliferative response, as compared with sham-infected cells. Proliferation of both CD4+ and CD8+ T cells was affected by HHV-6. Taken together, our data show that infection of T cells by HHV-6 results in immune suppression characterized by a downregulation of IL-2 mRNA and protein synthesis accompanied by diminished cellular proliferation.

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Induction of neonatal tolerance to H-2k in B6 mice does not allow the emergence of T cells specific for H-2k plus vaccinia virus.

Journal of Experimental Medicine ◽

10.1084/jem.156.3.810 ◽

1982 ◽

Vol 156 (3) ◽

pp. 810-821 ◽

Cited By ~ 3

Author(s):

D H Schwartz ◽

P C Doherty

Keyword(s):

T Cells ◽

T Cell ◽

Vaccinia Virus ◽

Somatic Mutation ◽

T Lymphocyte ◽

Cytotoxic T Lymphocyte ◽

Spleen Cells ◽

Cell Ontogeny ◽

Stimulation Of ◽

Tolerized Mouse

Thymocytes and spleen cells from C57BL/6 mice (H-2b) neonatally tolerized to H-2k alloantigens do not generate an anti-vaccinia response restricted to H-2Kk when adoptively transferred to appropriate irradiated hosts. This is in sharp contrast to the case for negatively selected C57BL/6 spleen cells acutely depleted of alloreactivity. No evidence for suppression was found in cell mixture experiments. We have shown elsewhere that our neonatally tolerized animals have a centrally induced delection-type tolerance in the absence of obvious suppression.2 We now suggest that in the neonatally tolerized mouse, chronic, central delection of anti-H-2k clones during early T cell ontogeny eliminates the major source of cells able to give rise, via somatic mutation and expansion, to anti-H-2Kk + vaccinia specific cytotoxic T lymphocyte precursors (CTL-P) in the adult. A similar mechanism may operate in the (k + b) leads to b chimera; however, the presence of H-2kxb accessory and presenting cells may permit the eventual generation (via cross-stimulation) of an H-2k-restricted vaccinia-specific repertoire. This would account for our observation of such "aberrant recognition" CTL-P emerging in the spleens of older (k x b) leads to b chimeras.

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The role of Raf-1 in the regulation of extracellular signal-regulated kinase 2 by the T cell antigen receptor.

Journal of Experimental Medicine ◽

10.1084/jem.180.1.401 ◽

1994 ◽

Vol 180 (1) ◽

pp. 401-406 ◽

Cited By ~ 43

Author(s):

M Izquierdo ◽

S Bowden ◽

D Cantrell

Keyword(s):

T Cells ◽

T Cell ◽

Map Kinases ◽

Interleukin 2 ◽

Antigen Receptor ◽

T Cell Antigen Receptor ◽

Cell Antigen Receptor ◽

Cell Antigen ◽

Constitutively Active

Triggering of the T cell antigen receptor (TCR) complex activates the serine/threonine kinase Raf-1 whose function is necessary for TCR induction of the interleukin 2 gene. Raf-1 has been identified as a candidate mitogen-activated protein (MAP) kinase kinase kinase (MKKK) and thus has the potential to couple the TCR to the activation of the MAP kinases such as ERK2. In the present study, the role of Raf-1 in ERK2 regulation of ERK2 in T cells has been explored. A constitutively active Raf-1 kinase, v-raf, or a dominant inhibitory Raf-1 mutant were expressed transiently from the pEF BOS vector in Jurkat cells and the effects of these Raf-1 mutants on a coexpressed ERK2 reporter was assessed. The action of the constitutively active Raf-1 was to stimulate the ERK2 kinase, whereas the dominant negative version of Raf-1 inhibited the ERK2 activation induced by triggering of the TCR. These data indicate a role for Raf-1 in the regulation of ERK2 in T cells.

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Interleukin-2 inhibits graft-versus-host disease-promoting activity of CD4+ cells while preserving CD4- and CD8-mediated graft-versus-leukemia effects

Blood ◽

10.1182/blood.v83.9.2560.2560 ◽

1994 ◽

Vol 83 (9) ◽

pp. 2560-2569 ◽

Cited By ~ 67

Author(s):

M Sykes ◽

MW Harty ◽

GL Szot ◽

DA Pearson

Keyword(s):

T Cells ◽

T Cell ◽

Graft Versus Host Disease ◽

Interleukin 2 ◽

Cell Subset ◽

Spleen Cells ◽

Host Disease ◽

Graft Versus Host ◽

T Cell Subset ◽

Graft Versus Leukemia

Abstract We have recently shown that a short course of high-dose interleukin-2 (IL-2) can markedly inhibit the graft-versus-host disease (GVHD)- promoting activity of donor CD4+ T cells. The difficulty in dissociating GVHD-promoting from graft-versus-leukemia (GVL) effects of alloreactive donor T cells currently prevents clinical bone marrow transplantation (BMT) from fulfilling its full potential. To test the capacity of IL-2 treatment to promote such a dissociation, we have developed a new murine transplantable acute myelogenous leukemia model using a class II major histocompatibility complex-positive BALB/c Moloney murine leukemia virus-induced promonocytic leukemia, 2B-4–2. BALB/c mice receiving 2.5 x 10(5) 2B-4–2 cells intravenously 1 week before irradiation and syngeneic BMT died from leukemia within 2 to 4 weeks after BMT. Administration of syngeneic spleen cells and/or a 2.5- day course of IL-2 treatment alone did not inhibit leukemic mortality. In contrast, administration of non-T-cell-depleted fully allogeneic B10 (H-2b) spleen cells and T-cell-depleted B10 marrow led to a significant delay in leukemic mortality in IL-2-treated mice. In these animals GVHD was inhibited by IL-2 treatment. GVL effects were mediated entirely by donor CD4+ and CD8+ T cells. Remarkably, IL-2 administration did not diminish the magnitude of the GVL effect of either T-cell subset. This was surprising, because CD4-mediated GVHD was inhibited in the same animals in which CD4-mediated GVL effects were not reduced by IL-2 treatment. These results suggest a novel mechanism by which GVHD and GVL effects of a single unprimed alloreactive T-cell subset can be dissociated; different CD4 activities promote GVHD and GVL effects, and the former, but not the latter activities are inhibited by treatment with IL-2.

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