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Query: UNIPROT:P14784 (IL-2 receptor)
 3,849 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Little is known about the cellular immune response during the acute phase of enterovirus infection. This was studied in patients with echovirus meningitis by analysing changes in the lymphocyte subset distribution both in blood and in cerebrospinal fluid (CSF) and their stage of activation. A significant increase of whole T-cell and CD4+ T-cell counts was observed in CSF in parallel with a slight decrease of T-cell percentage in blood. Activation of the cellular immune response is supported by the observation of elevated neopterin levels in serum and CSF. However, the phenotypic markers of T-cell activation, IL-2 receptor (CD25), and HLA-DR antigens were not detected in blood or in CSF.
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PMID:Evidence for T-cell involvement during the acute phase of echovirus meningitis. 146 Apr 59

Cross-linking the T-cell receptor-associated CD3 complex using the immobilized monoclonal antibody OKT3 can induce low levels of proliferation of purified resting T cells. The effect of coimmobilizing a monoclonal antibody 19H8 specific for the alpha-chain of the integrin VLA-4 on T-cell activation was evaluated. The level of proliferation induced by coimmobilization of the anti-VLA-4 with OKT3 was about 2- to 3-fold over proliferation induced by maximal OKT3 stimulation. The costimulatory activity of 19H8 was dependent on CD3 stimulation since immobilized 19H8 by itself did not induce proliferation. IL-2 secretion was found to be increased over 2-fold with 19H8 costimulation. Addition of exogenous IL-2 resulted in enhanced proliferation of both OKT3 and OKT3 plus 19H8-stimulated cells, but T cells coactivated with 19H8 exhibited a greater capacity to proliferate in response to exogenously supplied IL-2. Analysis of IL-2 receptor expression by flow cytometry revealed that the percentage of CD25-positive cells activated with either OKT3 or OKT3 plus 19H8 is comparable, but the mean fluorescence of cells coactivated with 19H8 is about 3-fold over cells stimulated with OKT3 alone. Dependency of the 19H8 enhanced proliferation on the IL-2/IL-2 receptor system was established by using IL-2-specific neutralizing antisera that reduced the proliferation of T cells activated with OKT3 alone or OKT3 plus 19H8 to comparable levels.2+hese results demonstrate that adhesion molecules may operate at the level of cytokine production and expression of its receptors to modulate the activation state of a cell.
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PMID:A VLA-4 alpha-chain specific monoclonal antibody enhances CD3-induced IL-2/IL-2 receptor-dependent T-cell proliferation. 146 62

We have continued our previous study of the inhibitory effects of factor VIII concentrates on IL-2 secretion by T cells. Experiments with an extended range of products confirm our previous conclusion that some but not all low, intermediate and high purity concentrates possess inhibitory activity on IL-2 secretion. The inhibition occurs almost immediately after addition of factor VIII concentrate and it was not possible to adsorb inhibitory activity with activated or non-activated cells; this suggests that the mechanism of inhibition involves interference with early T cell activation events rather than simple blocking of cell surface components by inhibitory molecules. The inhibitory components were shown to reside in different molecular weight fractions of concentrates. A strongly inhibitory component of approximately 200 kD and a minor species of approximately 60 kD were identified in strongly inhibitory concentrates. Some products contained a dialysable inhibitory substance which is most likely a salt as it was also present in some formulation buffers. The proportions of the inhibitory components varied widely between products. We have found that the pattern of inhibition using in vitro systems reflects that observed using a mouse in vivo antigen challenge method. In addition we have shown that the previously reported concentrate mediated inhibition of lectin induced low affinity IL-2 receptor (CD25) is mainly a consequence of diminished IL-2 secretion rather than a 'direct' effect on CD25 expression. Considering the wide variation between products of the same purity group, caution should be exercised in drawing conclusions concerning the immunosuppressive effects of a particular type of concentrate in haemophilia patients from study with only one product from that group.
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PMID:Mechanisms of inhibition of T cell IL-2 secretion by factor VIII concentrates. 148 38

We recently demonstrated that IL-2 is produced by reactive T cells in CD25-positive malignant lymphomas (ML). Using in situ hybridization, we investigated IL-6 mRNA expression in these CD25-positive ML. The ML tested included 9 anaplastic large cell lymphomas and 3 B-diffuse large cell lymphomas. Five CD25-negative ML were studied as controls. We show that IL-6 producing cells are present in all these ML. The density of positive cells was heterogeneous from case to case. However 3 cases of CD25-positive ML showed a dramatically higher density of IL-6 producing cells (70, 50, 43 producing cells per 10,000 cells, respectively) as compared to the other 9 cases of CD25-positive ML (mean 6.03 +/- 2.1 per 10,000). Morphological and topographical data suggested that several types of cells including fibroblasts, lymphocytes, macrophages and endothelial cells may synthesize IL-6. A combination of immunohistochemistry and in situ hybridization showed that reactive T cells and endothelial cells express the IL-6 gene whereas CD30-positive ML cells do not express this gene. Previous studies showed that IL-6 was capable to induce IL-2 receptor expression as well as production of IL-2 and stimulation of lymphomatous cells growth. Our present results indicate that the paracrine production of this cytokine may play a role in the proliferation of malignant lymphomas.
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PMID:IL-6 mRNA expression in CD25 positive malignant lymphomas. 149 62

The in vitro mitogenic properties of polyclonal antithymocyte and antilymphocyte globulins (ATG) on peripheral blood mononuclear cells were investigated. The ATG were mitogenic in a dose-dependent manner with maximal proliferation observed at 250 or 500 micrograms/ml. ATG activated blastogenesis of CD4+, CD8+, and CD57+ (NK cells) lymphocytes. The ATG induced interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) gene expression and lymphokine secretion in cell culture supernatant and IL-2 receptor (CD25) expression. At submitogenic concentrations ATG potentialized the effect of phorbol esters on T cell proliferation, but not that of calcium ionophore. The mitogenic effect of ATG was not abrogated by monocyte depletion indicating that like CD2 monoclonal antibodies (mAbs) ATG activate T cells via a monocyte-independent pathway. CD3 and CD2 mAbs which activate T cells without binding to B surface determinants stimulated the proliferation of B cells and their differentiation into immunoglobulin (Ig)-secreting cells. In contrast, ATG induced only a transient B cell activation, but failed to support B cell differentiation into Ig-secreting cells despite the secretion of IL-2. These properties shared by ATG obtained in horses or rabbits by immunization with different cell types appear to differ from those of other T cell mitogens.
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PMID:Monocyte-independent T-cell activation by polyclonal antithymocyte globulins. 151 79

The CD25 (IL-2-R alpha) cell surface glycoprotein expressed transiently during T-cell activation is implicated in the high affinity IL-2 receptor. This paper shows that cell-free supernatants from chronically HIV-infected promonocytic cells spontaneously produce a soluble factor which inhibits CD25 expression on PHA-activated human PBMC. We purified the CD25 expression inhibitory activity by a factor 12,350, using XM50 ultrafiltration, Superose 12 molecular sieving chromatography and MonoQ anion-exchange chromatography. Then we associated this activity to one single spot (M(r) 29,000, pI 6.8) on an O'Farrell two-dimensional gel. Our data demonstrate that this protein (M(r) 29,000, pI 6.8) is released from HIV-infected promonocytic cells and suggest that this factor is a new monokine regulating the T-cell activation process.
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PMID:Purification and identification of a CD25 expression inhibitory protein from cell-free supernatants of chronically HIV-infected promonocytic cells. 151 55

We previously reported that natural killer (NK) cells that had infiltrated renal-cell carcinoma (RCC) proliferated vigorously in culture with interleukin-2 (IL-2) and lysed autologous tumor cells. In this study, we investigate the susceptibility of RCC cells to NK-cell lysis and their ability to stimulate proliferation and increase phenotypic expression and function of NK cells. Cells from primary culture of RCC (p-RCC cells) were significantly more susceptible to the lysis mediated by human NK3.3 clones than were cells from primary culture of metastatic melanomas. Both RCC-cell clones and cells from primary culture of non-tumorous kidneys were also susceptible to lysis by NK3.3 clones and IL-2-activated peripheral blood lymphocytes (PBLs). Incubation of NK3.3 clones with p-RCC cells in the absence of IL-2 induced proliferation of NK3.3 clones, whereas incubation with cells from primary culture of metastatic melanomas, K562 cells, or any others tested did not. The p-RCC cells from earlier passages were more potent inducers of NK-cell proliferation than were those from older passages. Cell-free culture supernatants of p-RCC cells with or without NK3.3 clones failed to induce NK-cell proliferation. Incubation of CD16+ NK cells purified from PBLs with p-RCC cells induced higher proliferation of the NK cells only in the presence of IL-2, whereas incubation with cells from primary culture of metastatic melanomas did not. Incubation of NK3.3 clones with p-RCC cells resulted in an increase in CD16, CD25 (IL-2 receptor-alpha), and HLA-DR antigen expression and cytotoxicity in NK3.3 clones. In summary, these results suggest that RCC cells are able to activate NK cells, potentially through cell-to-cell interaction.
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PMID:Human renal-cell carcinoma cells are able to activate natural killer cells. 153 4

Two features of simian immunodeficiency virus (SIV) infection are emphasized: a transitory decrease in CD4 T cells in the first 2 weeks of infection followed by CD8 T-cell rise, and immune cell activation occurring by 4 weeks and persisting throughout the illness. The short-term changes included a fall in CD4 T cells by 2 weeks with partial recovery by 4 weeks and a CD8 rise that starts at 2 weeks. Subsequent characterization of CD4 T cells showed reduced expression of HLA-DR and CD25 (IL-2 receptor alpha chain) antigens later in SIV infection. Immune cell activation is evident in increased serum levels of neopterin and soluble CD8 antigen. Serum beta 2-microglobulin changes are less marked. Activation of CD8 T cells is reflected by increased percentages of cells expressing HLA-DR antigen. The B-cell numbers increased late in the course of SIV infection. Increased expression of the CD78 (Leu 21) activation phenotype was also seen in some monkeys. The immune activation changes (serum neopterin levels) induced by SIV infection in rhesus macaques appear to be associated with duration of illness, although the number of monkeys observed until death were too few for conclusive data. Thus, immune activation as well as T-cell deficiency may reflect significant immunopathogenic processes in SIV-induced disease.
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PMID:Acute lymphoid changes and ongoing immune activation in SIV infection. 154 74

A unique feature of both human T-cell leukemia virus type I (HTLV-I) carriers and subjects with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a chronic inflammatory disease of the nervous system, is the presence of large numbers of activated T cells that spontaneously proliferate in vitro. We have investigated the mechanisms of T-cell activation by HTLV-I in freshly isolated blood T cells and in naturally infected T-cell clones obtained by direct single-cell cloning from patients with HAM/TSP. Both CD4+ and CD8+ HTLV-I-infected T-cell clones showed the unusual ability to proliferate in the absence of exogenous interleukin 2 (IL-2). Nevertheless, HTLV-I-infected clones were not transformed, as they required periodic restimulation with phytohemagglutinin and feeder cells for long-term growth. Irradiated or fixed HTLV-I-infected clones were found to induce the proliferation of blood T cells when cocultured, which we refer to as THTLV-1-T cell activation. This THTLV-1-T cell-mediated activation was blocked by monoclonal antibodies (mAbs) against CD2/lymphocyte function-associated molecule 3 (LFA-3), LFA-1/intercellular cell-adhesion molecule (ICAM), and the IL-2 receptor but not by mAbs against class I or class II major histocompatibility complex molecules, HTLV-I gp46, or a high-titer HAM/TSP serum. Spontaneous proliferation of blood T cells from HAM/TSP patients could also be inhibited by mAbs to CD2/LFA-3, LFA-1/ICAM and to the IL-2 receptor (CD25). These results show at the clonal level that HTLV-I infection induces T-cell activation and that such activated T cells can in turn stimulate noninfected T cells by cognate THTLV-1-T cell interactions involving the CD2 pathway.
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PMID:T-cell activation by autologous human T-cell leukemia virus type I-infected T-cell clones. 154 69

An impermeable thiol blocker has been used to investigate the role of sulphydryl (SH) groups in the production of and responsiveness to IL-2 by normal human T lymphocytes. Surface SH blockade of mononuclear cells prior to incubation with mitogen (phytohaemagglutinin, concanavalin A, CD3 MoAb) had no effect on production of IL-2 but markedly impaired cellular responsiveness to exogenous IL-2. Studies using MoAbs indicated that this effect was accompanied by decreased expression of both the CD25 and p75 subunits of the IL-2 receptor. Blocking surface SH groups did not affect binding of IL-2 to p75 on unstimulated mononuclear cells, but inhibited binding to high-affinity receptors on a T lymphoma cell line. The data are consistent with the hypothesis that sulphydryl groups on the IL-2 receptor are required for its function and may be involved in the interaction of the CD25 and p75 subunits leading to generation of the high-affinity binding site. The surface thiol identified on the IL-2 receptor may be a candidate for oxidation on cells from patients with chronic inflammatory diseases such as rheumatoid arthritis and thus contribute to the aberrant function of T cells in these patients.
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PMID:Modulation of human T cell functions by surface sulphydryl groups: differential effects on IL-2 production and responsiveness. 156 2


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