Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P14784 (IL-2 receptor)
 3,849 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Stimulation of T-lymphocytes derived from some patients with common variable immunodeficiency (CVID) syndrome results in defective proliferation. The underlying mechanism is related to the inability of stimulated cells to secrete IL-2 while the expression of IL-2 receptor (IL-2R) is normal. We have identified a patient whose peripheral T-cells failed to proliferate and secrete IL-2 upon stimulation. The addition of recombinant IL-2 restored proliferation. The defect did not seem to be caused by accessory cell failure since the patient's adherent cells produced IL-1 and IL-6, and addition of allogeneic irradiated cells did not induce proliferation. Stimulation of CVID T-cells with phorbol esters and Ca2+ ionophore induced both IL-2 secretion and proliferation, indicating the absence of a defect in the transcription and/or translation of the IL-2 gene. The patient's T-cells expressed high levels of CD3. The majority of T-cells expressed the CD38 molecule which is normally found on thymocytes or activated T-cells but not peripheral blood T-cells and HLA-DR, another activation marker. However, CD25 (the IL-2R) and CD1, a marker of more immature thymocytes, were not expressed. Finally, the patient's cells were sensitive to an in vitro corticosteroid treatment. The possibilities that this patient's T-cells represent anergic T-cells or not fully matured thymocytes are discussed.
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PMID:An unusual T-cell surface phenotype in vivo correlates with the failure to proliferate and produce IL-2 in vitro in a patient with common variable immunodeficiency. 128 May 40

The effects of syncytiotrophoblast plasma membrane vesicles (STPM) on stimulated Jurkat leukemic T cells have been investigated. STPM inhibited IL-2 production and the expression of protein P55 of the IL-2 receptor (IL-2R P55), when Jurkat cells were stimulated by a combination of calcium ionophore A23187 (CaI) + phorbol 12-myristate 13-acetate (PMA). STPM also inhibited IL-2R P55 when cells were stimulated by PMA alone, a situation in which IL-2 production is negligible. On the other hand, STPM had no effect on the sustained mobilization of intracellular Ca2+ induced by CaI nor on the PKC-dependent CD3 down regulation induced by PMA. Finally STPM had no effect on intracellular cAMP levels. These results show that (i) the inhibitory effect of STPM on IL-2R P55 expression is independent of the inhibition of IL-2 production, and (ii) the inhibitory effects of STPM are at least partially independent of phosphatidylinositol 4,5-bisphosphate hydrolysis. They suggest that STPM affect a signaling pathway activated by PMA but possibly PKC independent.
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PMID:Inhibitory effect of human syncytiotrophoblast plasma membrane vesicles on Jurkat cells activated by phorbol ester and calcium ionophore. 130 91

The early events of signal transduction associated with interleukin-2 (IL-2) binding to its receptor were examined using a human IL-2 dependent T-cell line, Kit225. Cell cycle analysis showed that 90% of Kit225 cells were in the G0/G1 phase after a 72-hr incubation in the absence of exogenous IL-2. At this point, stimulation of the cells with IL-2 resulted in the rapid initiation of RNA and DNA synthesis by 9 and 20 hr, respectively. Within 5 min after addition of IL-2, rapid activation of tyrosine and ribosomal S6 kinases was detected. Addition of IL-2 also increased mRNA levels for c-fos, c-myc, IL-2 receptor alpha, and IL-2 receptor beta chain. These events increased in the absence of detectable changes in free cytosolic [Ca2+]i, inositol phosphate metabolism, or the activity of several kinases including cAMP-dependent protein kinase, Ca2+/calmodulin-dependent protein kinase, or protein kinase C. These findings demonstrate that the signals triggered by IL-2 binding to its receptors are quickly transduced into the nucleus with increased mRNA transcription of activation-associated genes. Furthermore, the data indicate that tyrosine and ribosomal S6 kinases may be important for IL-2-induced cell growth.
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PMID:Signal transduction by interleukin 2 in human T cells: activation of tyrosine and ribosomal S6 kinases and cell-cycle regulatory genes. 131 23

The role of the CD4 molecule in activation of T-helper cells was examined by investigating the effect of an anti-CD4 monoclonal antibody (Leu3a) in conventional peptide antigen-specific cloned T-helper cells that are also reactive to staphylococcal enterotoxin B (SEB). These T-helper cell clones are CD4+/CD45RO+/T-cell antigen receptor beta-chain variable region 12-positive and can respond to nominal peptide antigens and SEB by proliferation in the presence of class II major histocompatibility complex-expressing accessory cells. Although antigen and SEB were comparable in their ability to induce proliferative responses, interleukin 2 (IL-2) production, and IL-2 receptor alpha-chain expression, stimulation with SEB failed to trigger phosphatidylinositol hydrolysis or a rise in the intracellular free calcium ion concentration. Leu3a treatment inhibited antigen-induced proliferative responses of T cells with concomitant suppression of IL-2 production and IL-2 receptor expression. In contrast, SEB-induced responses were unaffected by Leu3a. These findings indicate that the functional consequences of binding (ligation) of conventional antigen and of superantigen with the T-cell receptor are distinct in the context of both signal transduction pathways and participation of CD4 molecules.
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PMID:Superantigen staphylococcal enterotoxin B-induced T-helper cell activation is independent of CD4 molecules and phosphatidylinositol hydrolysis. 135 2

In the immunosuppressed burn patient serum levels of both IL-2 and a soluble form of IL-2 receptor alpha (sIL-2R alpha) are significantly elevated. Strikingly, the production of these markers by the in vitro activated patients' cells is decreased. This study examines the role of IL-2 in the decreased production of the sIL-2R alpha in vitro in patients with major burns (n = 18, 30 to greater than 70% total body surface area). Peripheral blood mononuclear cell (PBMC) cultures from patients with highly elevated serum sIL-2R alpha, and from healthy controls (n = 12) were activated with concanavalin A (Con A) at initiation. In patients' cultures mitogen-induced increments of sIL-2R alpha levels were significantly lower. There was a significant negative correlation (r = 0.64, P less than 0.001) between a high serum sIL-2R alpha level and a decreased lectin-induced sIL-2R alpha release in vitro. Low levels of sIL-2R alpha in patients' samples were not normalized by increasing the number of T lymphocytes. Also exogenous rIL-1 was without effect, whereas rIL-3 increased sIL-2R alpha release in some cultures. However, sIL-2R alpha levels were significantly increased in patients' cultures by (i) addition of exogenous IL-2; (ii) removal of adherent cells; (iii) addition of cyclooxygenase inhibitor, indomethacin; (iv) bypassing cell surface activation by the combination of the calcium ionophore A23187 and the phorbol ester 12-o-tetradecanoyl acetate. The cyclic AMP-elevating drug, forskolin, abrogated the ability of exogenous IL-2 to increase sIL-2R alpha production. Thus, in the burn patient, the reduced in vitro sIL-2R alpha release appears to relate to abnormalities in IL-2 production and action mediated through its functional surface receptor. Elevated levels of sIL-2R alpha in vivo may, therefore, reflect systemic activation of T lymphocytes in response to biologically active IL-2.
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PMID:IL-2 regulation of soluble IL-2 receptor levels following thermal injury. 138 3

The cytochalasans, fungal metabolites that interact with actin, can affect lymphocyte proliferation; high concentrations inhibit lectin-induced proliferation and low concentrations augment it. The phorbol ester tumor promoter, PMA, alone is not mitogenic for primary lymphocytes but enhances the activity of mitogenic lectins. Because the cytochalasans have been reported to increase intracellular Ca2+ and because PMA activates protein kinase C, lymphocytes were treated with PMA and cytochalasin B (CyB) to determine if this combination would induce DNA synthesis. While this treatment by itself did not cause proliferation, lymphocytes cultured with PMA and CyB overnight, washed, and recultured with IL-2 proliferated to the same degree as lymphocytes stimulated with Con A. Three different cytochalasans, cytochalasin B, cytochalasin D, and chaetoglobosin C, all of which bind to cellular actin with different affinities and only one of which affects glucose transport, induced IL-2 receptors in combination with PMA. Flow cytometric analysis with an antibody to the IL-2 receptor alpha subunit confirmed the induction of receptors on CD8+ cells. However, no IL-2 was produced after the exposure of lymphocytes to the combination of cytochalasans and PMA. Therefore, there was sufficient signal to induce IL-2 receptor expression but not to induce IL-2.
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PMID:Cytochalasans and PMA induce IL-2 receptors on CD8+ lymphocytes. 139 84

Four specific interleukin-2 (IL-2) surface binding proteins can be detected by covalent cross-linking of [125I]IL-2 to rat spleen cells that have been activated with various stimuli including concanavalin A (Con A), phytohaemagglutinin (PHA), calcium ionophore, and phorbol dibutyrate (PDB) with or without calcium ionophore. These four cross-linked proteins could not be demonstrated in either unstimulated T cells or in activated T cells when binding was performed in the presence of a 20-100-fold excess of unlabelled IL-2. The molecular weights of the four cross-linked proteins, after subtraction of the molecular weight contribution of IL-2 are: 53,000, 70,000, 90,000 and 118,000. The 53,000 MW protein was identified as the rat IL-2 receptor (IL-2R) alpha-chain by immune precipitation. Additionally, results suggest that the rat IL-2R alpha-chain is tightly complexed to both the 118,000 and 90,000 MW IL-2 binding proteins. Purification of surface labelled proteins from activated cells using IL-2 affinity chromatography yields four proteins with similar molecular weight to those identified by cross-linking plus an additional non-ligand cross-linked protein of 46,000 MW. The 46,000 MW band may be a non-binding associated protein since it was not seen following [125I]IL-2 binding cross-linking. Tryptic digests and two-dimensional separation of the affinity-isolated proteins indicate that unique peptide maps are generated for the 46,000, 53,000 and 70,000 MW proteins and excludes the possibility that the bands identified by cross-linking represents cross-linking of multiple ligands to the 53,000 MW subunit. However, the 90,000 and 118,000 MW bands yield peptide maps that closely resemble each other suggesting that these binding proteins may be related. These results suggest that at least four IL-2 surface binding proteins may constitute the rat IL-2R system.
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PMID:Four interleukin-2 surface binding proteins detected in rat spleen cells. 147 80

The calcium ionophore, A23187, when used alone was found to induce proliferation of murine T cells, at concentrations of 0.5-1 mM. This response required the presence of syngeneic splenic adherant cells (SAC) as a source of accessory cells. Interestingly, only CD4+ T cells but not CD8+ T cells or B cells responded to the calcium ionophore by proliferation. The inability of CD8+ T cells or B cells to respond was not related to decreased elevation in the intracellular ionized calcium [Ca2+]i concentration induced by the ionophore, because activated CD4+ T, CD8+ T and B cells all exhibited similar elevation in [Ca2+]i. The inability of CD8+ T cells to respond to calcium ionophore was probably due to insufficient production of autocrine growth factors, such as IL-2, inasmuch as the addition of exogenous IL-2 could completely restore the CD8+ T cell responsiveness. Also, exogenous rIL-1 could partially restore purified T cell response to calcium ionophore, whereas, rIL-6 failed to do so. IL-2, but not IL-4, acted as an autocrine growth factor for T cells responding to the calcium ionophore in the presence of SAC, since, antibodies against IL-2 or IL-2 receptor (IL-2R) but not against IL-4, could inhibit the T cell proliferation. Furthermore, exogenous rIL-2 but not rIL-4 supported the proliferation of T cells to calcium ionophore in the absence of accessory cells. Our results suggest that murine lymphocytes exhibit heterogeneity in their proliferative responsiveness to calcium ionophore and that this may not depend on the early activation signal such as the elevation in [Ca2+]i) induced by the ionophore but may depend on subsequent signals which regulate endogenous growth factor production.
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PMID:Murine lymphocytes exhibit heterogeneity in their proliferative responsiveness to calcium ionophore. 148 6

Leukocyte activation is known to involve cell membrane potential changes. Phenobarbital, an anesthetic and anticonvulsant that can inhibit neuronal membrane depolarization, may also affect leukocyte activation. Measuring membrane potential, actin polymerization, chemotaxis, superoxide production, lymphocyte proliferation, intracellular calcium concentration, and cytokine production, we found that phenobarbital at a concentration of 15-30 micrograms/ml, which is considered a therapeutic serum level for controlling seizures, did not affect polymorphonuclear neutrophil (PMN) activation. At levels higher than 100 micrograms/ml, phenobarbital significantly suppressed formylmethionyl-leucyl-phenylalanine (fMLP)-induced chemotaxis. Concentrations greater than 300 micrograms/ml also inhibited phorbol myristate acetate-stimulated membrane potential change. In contrast, 30 micrograms/ml phenobarbital significantly inhibited lymphocyte proliferation stimulated by phytohemagglutinin (PHA) and pokeweed mitogen. This concentration of phenobarbital also suppressed the increase of intracellular free calcium induced by PHA. However, only a higher concentration of phenobarbital (300 micrograms/ml) was able to inhibit PHA-induced interleukin-2 (IL-2) production and suppress the proliferation of PHA-induced IL-2 receptor-bearing lymphocytes. These results suggest that concentrations of phenobarbital associated with anticonvulsive levels do not affect PMN activation but suppress lymphocyte activation, possibly by affecting intracellular signal transduction.
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PMID:Effects of phenobarbital on leukocyte activation: membrane potential, actin polymerization, chemotaxis, respiratory burst, cytokine production, and lymphocyte proliferation. 150 69

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


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