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

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

A 56-year-old man with refractory B-cell lymphocytic non-Hodgkin's lymphoma was treated in a Phase II study with interleukin-2 (IL-2) (Roussel-Uclaf, Romainville, France). The patient had involvement of multiple lymph nodes and medullary and peripheral blood (3.6 x 10(9) monoclonal CD19-positive [CD19+] B-lymphocytes/l). After a 5-day cycle of IL-2 treatment, an eightfold increase of the monoclonal CD19+ population was observed (27 x 10(9) monoclonal CD19+ cells). The lymphocytosis decreased dramatically during the second cycle (days 15 to 19) of IL-2 treatment, resulting in 6 x 10(9)/l peripheral lymphocytes, with 5.5 x 10(9) B-lymphocytes. As soon as day 20, peripheral B-cells again increased considerably, with 32 x 10(9) CD19+ cells/l at day 27. The CD19+ population remained monoclonal as assessed by kappa/lambda cell-surface phenotyping and kappa gene rearrangement evaluation. Kinetics of the monoclonal B-lymphocyte response to IL-2 paralleled the natural killer/lymphokine-activated killer and T-cell response, with a 4-day latency period, suggesting an indirect enhancing effect of IL-2. Before and during IL-2 treatment, peripheral B-lymphocytes never expressed detectable levels of the p55 IL-2 receptor. However, the p75 IL-2 receptor was expressed significantly in the IL-2-responsive monoclonal B-cell population. Tumor necrosis factor alpha, a known (in vitro) B-cell tumor growth factor, reached high serum levels during IL-2 treatment. Response evaluation at day 45 showed stability of the lymph node involvement and the marrow lymphocyte infiltrate. At day 45, peripheral B-cell lymphocytosis was 7.5 x 10(9)/l. To the knowledge of the authors, this is the first report of an in vivo IL-2-induced reversible increase of peripheral monoclonal B-cell lymphocytosis.
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PMID:Interleukin-2-induced increase of a monoclonal B-cell lymphocytosis. A novel in vivo interleukin-2 effect? 156 83

Early murine fetal thymocytes express functional, high affinity IL-2 receptors as determined by: (i) the presence of IL-2R beta chain (p75) mRNA; (ii) IL-2 (10 U/ml) induced cell proliferation/cellular maturation in lobe submersion cultures (LSC). Under the influence of IL-2, early thymocytes differentiate in vitro into more mature, early single positive CD4-CD8+ followed in vivo by double positive CD4+CD8+ and single positive CD4+CD8-T and CD4-CD8+ thymocytes. Specific intoxication of high affinity IL-2R positive thymocytes by recombinant interleukin-2-diphtheria toxin-related fusion protein (DAB486-IL-2) results in transient, dose dependent blockade of in vivo and in vitro thymocyte maturation. DAB486-IL-2 induced effects upon in vivo maturation are reversible within 2 weeks after cessation of drug administration. Taken together, these results demonstrate the expression of functional, high affinity IL-2 receptors on early thymocytes. Elimination of high affinity IL-2 receptor positive thymocytes with DAB486-IL-2 results in transient blockade of T cell maturation. Since DAB486-IL-2 is now in clinical trial, it is reassuring to note that it does not permanently disrupt thymic maturation.
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PMID:Intoxication of high affinity IL-2 receptor positive thymocytes blocks early stages of T cell maturation. 159 Dec 19

In the present study, we show by Northern blot analysis and enzyme linked immunosorbent assay that the Hodgkin's disease (HD)-derived cell lines HDLM-2 and KM-H2 express a variety of cytokine genes either constitutively or upon induction with phorbol ester 12-O-tetradecanoylphorbol-13-acetate. Cytokine genes expressed by HD-derived lines include granulocyte-macrophage colony-stimulating factor (CSF), macrophage-CSF, interleukin (IL)-1-alpha, IL-3, IL-5, IL-6, IL-8, leukemia inhibitory factor, tumor necrosis factor-alpha, tumor necrosis factor-beta, and transforming growth factor-beta, while transcripts and the corresponding proteins for granulocyte-CSF, IL-1-beta, IL-2, IL-4, IL-7, IL-10, and the JE/macrophage chemoattractant and activating factor gene were not detectable in cytoplasmic RNA and culture supernatants obtained from both lines. In addition, IL-2 receptor (R) p55 and macrophage-CSF R (c-fms) genes were expressed by both lines. HDLM-2, but not KM-H2 cells, exhibited the IL-6 R p80 and the IL-2 R p75 chain. Analysis of nuclear proteins that bind to oligonucleotides containing the consensus sequences of the transcription factors activation protein 1, nuclear factor (NF) kappa B, and NFAT 1 revealed a pattern for HD lines resembling that of activated T-cells: HDLM-2 and KM-H2 cells constitutively expressed NF binding to the NF of activated T-cells (type 1), previously described to be T-cell specific. In addition, NF kappa B-binding proteins obtained from both lines showed, in electrophoretic mobility shift assays, the same migration pattern as T-cell-derived proteins but differed from monocyte- and B-cell-derived proteins. UV cross-linking experiments confirmed that NF kappa B-binding proteins of M(r) 85,000, 75,000, and 50,000/55,000 were detectable in nuclear extracts obtained from T-cells and both HD lines, while monocytes and B-cells displayed the M(r) 50,000/55,000 and 75,000 NF kappa B complex only. Both HD lines also constitutively expressed transcripts for c-fos and c-jun, which are involved in heterodimeric formation of the transcription factor activation protein 1, as well as for the NF kappa B/KBF1 gene.
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PMID:Expression of cytokine genes, cytokine receptor genes, and transcription factors in cultured Hodgkin and Reed-Sternberg cells. 159 93

Stimulation of the interleukin-2 (IL-2) receptor results in phosphorylation and activation of cytosolic Raf-1 serine/threonine kinase. Herein, we report that enzymatically active Raf-1 is physically associated with the IL-2 receptor beta chain (p75) in T-cell blasts. Following stimulation with IL-2, Raf-1 dissociates from the IL-2 receptor complex and translocates to the cytosol. Genistein, a protein tyrosine kinase inhibitor, prevents the dissociation of enzymatically active Raf-1 from the ligand-stimulated IL-2 receptor complex. These data favor a model of IL-2 receptor activation in which an IL-2-activated protein tyrosine kinase phosphorylates the IL-2 receptor and/or receptor-bound Raf-1. Following tyrosine phosphorylation, enzymatically active Raf-1 dissociates from the IL-2 receptor and translocates into the cytosol.
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PMID:Interleukin-2 (IL-2) induces tyrosine kinase-dependent translocation of active raf-1 from the IL-2 receptor into the cytosol. 163 73

Resting natural killer (NK) cells express the p75 chain of the IL-2 receptor (IL-2R beta) and most NK cells express the CD2 (erythrocyte rosette) receptor. The cell adhesion molecule, LFA-3, is a natural co-ligand for CD2. Tac antigen (IL-2R alpha), a p55 IL-2R subunit, can be expressed after NK activation and may play a role in IL-2-induced NK proliferation. Little is known of the molecular mechanisms underlying cytokine production in NK cells. We investigated the roles of IL-2R alpha, IL-2R beta, and CD2/LFA-3 in the molecular regulation of NK cell granulocyte/macrophage-colony-stimulating factor (GM-CSF) production. Enriched populations of peripheral blood NK cells were separated into CD16-positive and CD16-negative fractions by flow cytometry; positively selected cells were greater than 97% positive for CD16 (the FcIII receptor for IgG which is present on almost all NK cells), less than 1% positive for the T cell antigen CD3, and did not demonstrate rearrangement of the T cell receptor beta chain gene by Southern blot. NK cell supernatants were harvested after 3-4 d of incubation with 0-100 U/ml IL-2, or after incubation with anti-CD2 (T11(3] MAb and sheep red blood cells (SRBC are a homologue for LFA-3). Parallel cell aliquots were harvested at 3-16 h for transcriptional run-on assays, S1 nuclease assays, and actinomycin D mRNA t1/2 determinations. IL-2-activated NK supernatants contained large amounts of GM-CSF (178 +/- 35 pg/ml) by ELISA as did supernatants from CD2-activated NK cells (T11(3) MAb + SRBC: 212 +/- 42) vs. less than 20 pg/ml for NK cells incubated alone or with either SRBC or T11(3) MAb alone. Sepharose-linked anti-CD3 MAb did not induce GM-CSF release from NK cells. By S1 analysis, both IL-2 and CD2 stimulation markedly augmented GM-CSF mRNA expression but with very different latencies of onset. IL-2R beta MAb inhibited greater than 85% of GM-CSF release from IL-2-activated NK cells and markedly suppressed IL-2-induced GM-CSF mRNA expression, whereas IL-2R alpha MAb even at 2,000-fold molar excess of IL-2 had little effect (less than 10%) on either GM-CSF release or mRNA expression. Run-on assays showed that GM-CSF is constitutively transcribed in NK cells and that IL-2 and CD2-activated cells had a three- to fourfold increased rate of GM-CSF transcription compared to nonstimulated cells. The t1/2 of GM-CSF mRNA in IL-2-activated NK cells was identical to that of unstimulated NK cells (15 min), whereas GM-CSF mRNA t1/2 in CD2-activated NK cells was increased 2.5-fold. We conclude that GM-CSF production in NK cells is regulated by both the IL-2Rbeta and the CD2 receptor but not by IL-2Ralpha, that both transcriptional and posttranscriptional signals act together to modulate the level of GM-CSF mRNA in NK cells, and that the molecular mechanisms underlying NK cell GM-CSF production are dependent in part on differential surface receptor activation.
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PMID:Production of granulocyte/macrophage-colony-stimulating factor by human natural killer cells. Modulation by the p75 subunit of the interleukin 2 receptor and by the CD2 receptor. 167 38

Our studies have analyzed pore-forming protein (PFP) mRNA expression in resting and stimulated human peripheral blood CD3- large granular lymphocytes (LGL), CD3+ T cells, and their CD4+ or CD8+ subsets. Signals that stimulate T cells to develop cytotoxic activity (i.e., IL-2 or OKT-3 mAb) led to the induction of PFP mRNA in T cells. The data indicated that IL-2 directly increased PFP mRNA in the CD8+ subset of T cells, in the absence of new DNA or protein synthesis. Abrogation of IL-2-induced PFP mRNA expression and cytotoxic potential of T cells by the anti-p75 IL-2 receptor mAb suggested that low numbers of p75 IL-2 receptors on CD8+ T cells were capable of transducing signals responsible for these IL-2-induced effects. The induction of T cell PFP mRNA via CD3, using OKT-3 mAb, was less rapid but greater than that caused by IL-2; however, a combination of PMA and ionomycin, which bypasses crosslinking of the TCR/CD3 complex, could not mimic this increase in PFP mRNA levels in T cells. The role of second messenger systems in regulating PFP mRNA expression remains to be determined. In contrast, high constitutive PFP mRNA expression was observed in CD3- LGL and these mRNA levels could not be enhanced by stimulation with IL-2. The cytotoxic potential of peripheral blood T cells and LGL induced in response to IL-2 correlated with IL-2-induced PFP mRNA levels in these cells and was consistent with PFP being one of several important molecules involved in the effector function of cytotoxic lymphocytes.
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PMID:Interleukin 2 induction of pore-forming protein gene expression in human peripheral blood CD8+ T cells. 169 Dec 63

Interleukin 2 (IL-2) induced activation of unstimulated resting natural killer (NK) cells or resting T-cells initially occurs following binding of IL-2 through the p75 receptor that is expressed primarily by these cells. However, this IL-2/p75 interaction induces TAC chain synthesis and formation of high affinity IL-2 receptor required for the proliferation of resting peripheral blood lymphocytes. In this study, we present data indicating that NK cells activated by in vivo IL-2 treatment, in contrast to resting NK cells, respond and proliferate to further IL-2 in vitro using primarily the p75 receptor with only a minor component of cells responding through the high affinity receptor. These in vivo activated NK cells minimally expressed the TAC chain and maintained this TAC negative phenotype while proliferating in response to IL-2. The primary involvement of the p75 receptor in the proliferative response of these cells to IL-2 was demonstrated by the need for concentrations of IL-2 higher than 44 pM to obtain a significant response and by the dramatic inhibition of this response by anti-p75 monoclonal antibody. Anti-TAC monoclonal antibody inhibited only the poor proliferation obtained at low doses of IL-2 suggesting a minor role for TAC and high affinity IL-2 receptors. This was in contrast to the partial inhibition of proliferation by anti-p75 or anti-TAC observed in unstimulated pretherapy peripheral blood lymphocytes suggesting that these cells respond to IL-2 through both high affinity receptors and intermediate affinity p75 receptors. The T-cells isolated from in vivo activated peripheral blood lymphocytes, despite expressing TAC, were not responsive to IL-2, suggesting that these cells express predominantly nonfunctional low affinity TAC receptors. NK cells activated by IL-2 in vivo represent a unique model system of IL-2 dependent cells that respond and proliferate to IL-2 essentially through the p75 IL-2 receptor.
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PMID:Natural killer cells activated by interleukin 2 treatment in vivo respond to interleukin 2 primarily through the p75 receptor and maintain the p55 (TAC) negative phenotype. 169 79

In this study, we have used radiolabeled IL-2 binding assays, Northern blot analysis, immunofluorescent flow cytometry and cell sorting, as well as proliferation and cytotoxicity assays to perform an extensive phenotypic and functional characterization of the IL-2 receptor in normal resting human peripheral blood lymphocytes. Our results indicate that almost all T cells (greater than 98%) express neither the high affinity IL-2 receptor nor the functional intermediate affinity p75 chain of the IL-2 receptor without prior activation. In contrast, most NK cells constitutively express the isolated intermediate affinity p75 IL-2 receptor. In addition, a subpopulation of NK cells, distinguished by high density expression of the NKH1 antigen, constitutively express the high affinity IL-2 receptor, in addition to an excess of the isolated intermediate affinity p75 IL-2 receptor. These NKH1bright+ cells exhibit a brisk proliferative response to IL-2, similar to that seen with antigen-activated T cells, yet do so in the absence of any known antigenic stimuli. No other resting peripheral blood lymphocyte population, including CD4+, CD8+, and CD20 cells, exhibits this property. The intermediate affinity p75 IL-2 receptor, as it exists in its isolated form on resting NK cells, does not transduce a growth signal equivalent to that seen in NK cells expressing the high affinity IL-2 receptor, despite doses of IL-2 that are known to fully saturate the isolated p75 chain. This strongly suggests that additional structural or functional components are involved in generating the proliferative response following the binding of IL-2 to the high affinity heterodimeric form of the IL-2 receptor. The constitutive expression of this functional high affinity IL-2 receptor on a small population of resting NK cells provides further evidence in support of a role for these cells in the host's early defense against viral infection or malignant transformation, before the more delayed but specific T cell response.
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PMID:Functional consequences of interleukin 2 receptor expression on resting human lymphocytes. Identification of a novel natural killer cell subset with high affinity receptors. 169 80

A number of markers which have been proposed to identify B cell subsets have been reassessed on human B cells, using an immunofluorescence technique optimized for sensitivity and an analytical mode which yields histograms showing the distribution of fluorescence on B cells. The results show that CD38, CD22, CD23, FMC6, and anti-IgM react with all blood B cells, albeit with a broad and complex distribution of fluorescence. CD5, CD9, CD10, CD43, and IgD can be regarded as subset markers since they give clearly bimodal distributions of fluorescence intensity. CD5 staining showed at least three populations, with a small number (3-5 per cent) of cells brightly stained and a population of variable size staining weakly. No clearly defined populations were seen with CD45R0, although staining was slightly above background. An antibody against the LAM-1 molecule reacted with all blood B cells. Expression of the IL-2 receptor p55 chain (CD25) was clearly bimodal, whereas the p75 chain was essentially negative on B cells. The relationship between subsets in blood and subsets in tissue, and between subsets identified by different markers in blood, is discussed.
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PMID:The expression of sub-population markers on B cells: a re-evaluation using high-sensitivity fluorescence flow cytometry. 172 68


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