UNIPROT:P14784 - FACTA Search

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

The effect of the CD28 activation pathway on the immunosuppressive action of CsA was assessed. Human peripheral blood lymphocytes were stimulated with anti-CD3, bryostatin (Bryo) a novel activator of protein kinase C (PKC) and anti-CD28 singly or in combination, to which graded doses of CsA were added to determine relative sensitivity. Proliferation, IL-2 production, and IL-2 receptor expression were assessed and the IC50 determined. Lymphocytes stimulated with Bryo exhibited a marginal proliferative response but expressed the IL-2 receptor despite the presence of CsA. Addition of anti-CD3 or anti-CD28 to Bryo-stimulated lymphocytes promoted a vigorous proliferative response. CsA effectively inhibited the proliferative response and IL-2 production induced with anti-CD3 and Bryo but did not inhibit the response of cells stimulated with anti-CD28 and Bryo. However, II-2 receptor expression in both sets of cultures were comparable due to the induction of IL-2 receptor by Bryo and was not inhibited by CsA. Costimulation of lymphocytes with anti-CD3 plus anti-CD28 resulted in a 2-3-fold enhancement of proliferation compared with lymphocytes stimulated with anti-CD3 alone. Addition of CsA to lymphocytes stimulated with anti-CD3 resulted in the dose-dependent suppression of the proliferative response and IL-2 production (IC50 = 10-25 nM) but less so for IL-2 receptor expression (IC50 = 100-150 nM). In comparison, the proliferative response and IL-2 production elicited by anti-CD3 + anti-CD28 was more resistant to the effects of CsA (IC50 = 100-200 nM). However, IL-2 receptor expression exhibited comparable sensitivity to CsA (IC50 = 100-200 nM) in the presence of anti-CD28. Combination drug:drug studies revealed that CsA and the protein kinase C inhibitor H-7 were additive for both anti-CD3 and anti-CD3 plus anti-CD28 response. On the other hand, the cGMP-dependent protein kinase inhibitor H-8 was synergistic with CsA in inhibiting the response of lymphocytes to anti-CD3 plus anti-CD28 but only additive for responses to anti-CD3. Taken together, these data suggest that CsA inhibits T cell activation at two distinct levels, leading to inhibition of IL-2 production and inhibition of IL-2 receptor expression. Activation of the CD28 pathway partially overcomes the inhibitory activity of CsA on IL-2 production and may be mediated by indirect activation of a cGMP-dependent protein kinase.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The effect of the CD28 activation pathway on the immunosuppressive action of cyclosporine. 164 6

The antimalignant cell activity of tumor necrosis factor (TNF) in many cell types can be enhanced by lithium chloride (LiCl). This study shows the in vitro effect of LiCl on the TNF-induced or interleukin 1 (IL-1)-induced expression of IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-3, IL-2, and the IL-2 receptor-alpha (IL-2R alpha). The levels of IL-6 and GM-CSF in the medium of TNF-treated L929 fibrosarcoma cells were increased by cotreatment with LiCl. In contrast, enhancement of IL-6 production by dibutyryl cyclic AMP or cycloheximide was not affected by LiCl. The production of IL-6 and GM-CSF was not correlated with sensitivity to TNF-mediated cell killing. IL-1 by itself had no measurable effects on L929 cells. However, LiCl potentiated the IL-1-induced synthesis of IL-6, GM-CSF, IL-3, and IL-2 in PC60 murine T-cell hybridoma cells. TNF alone induced only GM-CSF production in these cells, but in the presence of LiCl, increased amounts of GM-CSF as well as small amounts of IL-2 and IL-6 could be detected. It is also shown that in these PC60 cells the expression of the IL-2R alpha was induced by TNF + LiCl treatment but not by TNF alone. IL-2R alpha expression was likewise considerably enhanced by IL-1 + LiCl treatment, as compared with treatment with IL-1 alone. The effects of LiCl on the TNF-induced and the IL-1-induced gene expression seem to be independent of the protein kinase A and C pathways. These results show that LiCl can modulate both TNF-mediated cytotoxicity and TNF-induced and IL-1-induced cytokine expression, suggesting that Li+ acts early in the TNF-signaling pathway, but at a step shared with the IL-1-signaling pathway.
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PMID:Lithium chloride potentiates tumor necrosis factor-induced and interleukin 1-induced cytokine and cytokine receptor expression. 165 81

Calcium ionophores such as ionomycin (IONO), CD3 antibody (CD3), or CD28 antibody (CD28) have been shown to stimulate T cells in a quite different fashion. However, each stimulator induces full activation of resting T cells in the presence of phorbol myristate acetate. Human T cells were activated with PMA + CD3, PMA + IONO, or PMA + CD28 and the inhibitory effects of dexamethasone (DEX) and cyclosporine were examined on [3H]-TdR incorporation, IL-2 production, and IL-2 receptor expression. Three inhibition patterns emerged: PMA + CD3 stimulation was DEX-sensitive and CsA-sensitive, PMA + IONO stimulation was CsA-sensitive but DEX-resistant, PMA + CD28 stimulation was DEX-sensitive but CsA-resistant. Although the degree of inhibition by DEX and CsA was different in [3H] TdR incorporation, IL-2 production, and IL-2 receptor expression assays, the inhibitory pattern of these drugs was similar in each of the assays, indicating that human T cell activation is differentially regulated by DEX and CsA depending on the stimulator.
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PMID:Differential regulation by dexamethasone and cyclosporine of human T cells activated by various stimuli. 165 6

Human cytomegalovirus (HCMV) immediate early (IE) genes act as trans-acting factors to upregulate various viral promoters. We used various IE plasmid constructs in transient transfection assays and demonstrated that the HCMV IE2 gene product upregulated expression from the interleukin (IL)-2 and IL-2 receptor (IL-2R) promoters and increased amounts of endogenous, steady-state IL-2 and IL-2R RNA. In marked contrast, the IE1 gene product, which can upregulate the major IE promoter and the IL-1 beta promoter, had no effect on the IL-2 and IL-2R promoters. These studies suggest a role for the HCMV IE2 gene product as a modulator of the inflammatory response associated with HCMV infection.
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PMID:The immediate early genes of human cytomegalovirus upregulate expression of the interleukin-2 and interleukin-2 receptor genes. 165 52

Northern blot analysis and a highly sensitive methodology for mRNA phenotyping, polymerase chain reaction (PCR), were used to explore the basis for the synergism between CD3/alpha beta T cell receptor (TCR) and the CD2 antigen-derived signals in promoting proliferation of T cells. Northern blotting of RNA isolated from highly purified normal human T cells revealed that crosslinking of anti-TCR-1 (a mAb directed at a framework determinant of the TCR) and OKT11 (a mAb directed at the SRBC-binding epitope of the CD2 antigen) induced the expression of the interleukin-2 gene and the gene for IL-2 receptor alpha, mRNA phenotyping by PCR revealed that crosslinkage of TCR with the CD2 antigen, and not independent crosslinking of TCR or the CD2 antigen, results in the induction of IL-2, IL-2 receptors alpha and beta, and IL-4-specific transcripts. Highly purified CD4+ T cells, as well as CD8+ T cells proliferated by crosslinking TCR with CD2 antigen. Moreover, crosslinkage of TCR with the CD2 antigen and not of either antigen with the CD4 antigen (on the surface of CD4+ T cells) or the CD8 antigen (on the surface of CD8+ T cells) resulted in marked proliferation. Our demonstration that the CD2 antigen-derived signal(s) contribute to the expression of growth promoting genes elicited via the TCR, and that the CD2 antigen is more efficient compared with the CD4 or CD8 antigen in evoking T cell proliferation, suggests that autoimmunity as well as alloimmunity might be regulated by targeting the CD2 antigen.
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PMID:The molecular basis for the synergism between the CD3/alpha beta T cell receptor and the CD2 antigen-derived signals in promoting T-cell proliferation. 167 15

Recent studies have demonstrated that cyclosporin A (CyA) exerts a beneficial effect on psoriasis. It remains unclear, however, whether T-cell immune responses are definitely impaired in psoriasis and whether the anti-psoriatic effect of CyA is mediated by interference with T-cell activation. To study these questions, 20 patients with severe psoriasis were treated with oral CyA (5 mg/kg/d) for 12 weeks and examined for several phenotypic and functional properties of peripheral blood T cells before and after therapy. The analyses included CD3, CD4, and CD8 phenotypes, IL-2 production and IL-2 receptor expression following Con A stimulation, proliferative responses to PHA, and in vivo responsiveness to a foreign antigen, PPD. When the values of patients before therapy and healthy individuals were compared, no statistically significant differences were detected in any of these analyses. Furthermore, none of these T-cell properties were changed after 12 weeks of treatment. To assess possible minor mutations in T-cell-related genes in psoriasis, the T-cell receptor beta-chain locus was analyzed by Southern hybridization. With a cDNA probe for C beta 1, a polymorphic fragment of congruent to 9 kb was detected in Eco RI digests in one of 20 patients and in four of 10 healthy individuals examined. No polymorphism was detected in Bam HI digests in any individual. These results fail to support the hypothesis that a general or "systemic" alteration in T-cell immunity plays a central role in the pathogenesis of psoriasis and in the action of CyA against this skin disorder.
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PMID:Genomic, phenotypic, and functional analyses of T cells in patients with psoriasis undergoing systemic cyclosporin A treatment. 167 38

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

It is well established that peripheral CD8+ and CD4+ T cells display different requirements for in vitro activation by mitogenic mAb. Most CD4+ T cells can be activated by anti-CD3 or mitogenic combinations of anti-CD2. In contrast, CD8+ T cells display minimal responses to CD3 activation, and no proliferation is observed via CD2 activation. Purified peripheral blood CD8+ T cells, stringently depleted of APC, have been studied for their capacity to respond to mAb directed against CD3, CD2 and CD28, used alone or in combination. It is demonstrated that proliferation can be induced by co-stimulation of CD2 and CD28. This does not require autologous APC. CD8+ T cells can also be activated by the combination of anti-CD3 plus anti-CD28 in the presence of APC, but only minimal cell proliferation is obtained in the absence of APC. The response via CD2 plus CD28 is IL-2-dependent, as demonstrated by the ability of mAb against the IL-2 receptor to block proliferation, and is almost completely inhibited by cyclosporine A (CsA). These results suggest that the signal generated by stimulation of CD28 in combination with CD2 differs from that seen with CD28 activation combined with either PMA or CD3. Induction of IL-2 gene activation in CD8+, CD28+ peripheral T cells may therefore require additional "second signals", which are not necessary for activation of CD4+ cells. One such signal might be the interaction between CD28 and its natural ligand.
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PMID:Activation of peripheral CD8+ T lymphocytes via CD28 plus CD2: evidence for IL-2 gene transcription mediated by CD28 activation. 167 47

Monoclonal antibodies were used to determine the relationships between epitopes on the p55 chain of the IL-2 receptor and high-affinity IL-2 binding. Five monoclonal antibodies to the human P55 chain of the IL-2 receptor were induced by immunizing mice with murine L cells that were transfected with human p55 cDNA. Since the p55 chain is the only human antigen expressed on these cells, all antihuman MABs thus generated were directed against this molecule. These antibodies were used to map epitopes on the p55 chain and determine their relationship to high-affinity IL-2 binding. Extensive flow cytometric studies with these MABs and a large panel of other anti-p55 MABs revealed three major patterns of competition. Type I MABs compete with anti-Tac extensively but not with antibodies of other groups. Type II MABs do not block anti-Tac but do block 7E11. Type III MABs do not block either type I or type II antibodies. 125I-IL2 competition studies under high-affinity conditions revealed that types I and II MABs inhibit IL-2 binding. Type III MABs can be resolved into two subgroups, one that inhibits IL-2 binding and one that does not. Together these data suggest that there are at least four distinct immunogenic epitopes on the human p55 chain, with three epitopes related to IL-2 binding. The competitive component evident by a change in Kd on the Scatchard plots suggests that all three epitopes are close to or part of the IL-2-binding site of the p55 chain. The noncompetitive component, as evidenced by the lower number of high-affinity IL-2 receptors induced by these antibodies, suggests that the same epitopes are also close to the site(s) of interaction between the p55 and p70 chains to form the high-affinity receptor. These studies indicated that the IL-2-binding site and site of interaction between the p55 and p70 chains are close together or identical. Modulation studies revealed that one type II antibody (7E11) modulates the p55 chain in the absence of IL2 and the p70 chain, thus revealing that modulation of the p55 chain can occur by an active process, and not merely passively comodulate by the p70 chain upon IL-2 binding. Modulation of the p55 chain alone has no proliferative effect on IL-2-responsive T lymphoblasts. Potentially this antibody-dependent modulation may be used to deliver toxin to activated lymphocytes.
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PMID:Immunogenic epitopes of the p55 chain of the IL-2 receptor. Relationships to high-affinity IL-2 binding and modulation of the p55 chain. 169 Apr 71

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

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