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)

In the present study the activation of purified human T lymphocytes by the calcium ionophore A23187 was analysed in the light of current concepts of receptor-linked inositol lipid metabolism. It was found that A23187 was only slightly mitogenic, with a narrow optimum at 400-500 nM. The proliferation could be blocked by anti-Tac ascites at 10(-3) dilution, suggesting an interleukin 2 (IL-2)-dependent pathway of activation. However, an unexpectedly large proportion of A23187-stimulated cells expressed the IL-2 receptor. Reculturing the cells with exogenous IL-2 after removal of A23187 resulted in strongly enhanced proliferation. Phorbol myristic acetate (PMA) at non-mitogenic concentrations exerted an extremely strong synergistic effect on A23187-induced cell proliferation, which was, again, mediated via an IL-2-dependent pathway. Supernatants of A23187-stimulated T cells did not contain detectable amounts of IL-2. Combination of PMA and A23187 resulted in considerable IL-2 production. It is concluded that A23187 induces the expression of IL-2 receptors without concurrent stimulation of IL-2 production, thus allowing only low levels of proliferation. Addition of exogenous IL-2 or of PMA restores the imbalance between the occurrence of IL-2 and its receptor and results in high rates of proliferation.
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PMID:Calcium ionophore A23187 induces interleukin 2 reactivity in human T cells. 393 26

In this study, we have investigated the ability of various cytokines to induce the maturation of acute lymphoblastic leukemia (T-ALL) cells with early T-cell phenotype. Leukemic blasts from 17 untreated T-ALL patients were assayed for their ability to acquire mature T-cell markers, CD3/T-cell receptor (TCR) in particular, after incubation with one or a combination of recombinant human interleukin-1 (IL-1), IL-2, IL-4, IL-7, and CD2-specific monoclonal antibody (MoAb). IL-7 or IL-2 induced the proliferation of some leukemic cells, whereas sequential cell treatment with CD2-MoAb and then IL-2 promoted CD3/TCR expression on nearly all CD2+ cells (15 of 16), except for 1 T-ALL that developed into CD3-CD16+CD56+ cells. Differentiation of T-ALL cells was also evidenced through the downregulation of CD34 precursor cell antigen, the generation of CD4+ and CD8+ cells from CD4+ CD8+ precursors, and the acquisition of mature T-cell functions. CD2 ligation induced a progressive increase of surface expression of IL-2 receptor alpha (IL-2R alpha) and IL-2R beta and an accelerated in vitro death of leukemic cells. The ligation of IL-2R by IL-2 rescued T-ALL cells from death and promoted their progression toward more mature cells expressing extracellular CD3/TCR alpha beta complexes. Intracellular analysis indicates that TCR alpha transcription and membrane translocation of both TCR alpha and TCR beta were promoted in these conditions. Analysis of intracellular signals transduced during T-ALL differentiation indicated that CD2-ligation induced Ca2+ influx and that the ligation of CD2 and IL-2R induced distinct tyrosine phosphorylation patterns. The addition of inhibitors of tyrosine phosphorylation abolished T-ALL cell differentiation, which suggests the involvement of tyrosine kinases in this phenomenon. Together, we showed the constant maturation of leukemic early T cells after stimulation of surface CD2 and the high-affinity IL-2R.
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PMID:Maturation of acute T-lymphoblastic leukemia cells after CD2 ligation and subsequent treatment with interleukin-2. 751 76

The neuropeptide arginine vasopressin (AVP) can replace the cytokine interleukin 2 (IL-2) as a T-cell mitogen for the induction of interferon gamma (IFN gamma) expression in splenic cultures. IL-2-like and IL-2 receptor immunoreactivity have been reported in different brain regions, under normal and pathophysiological conditions. Regulatory functions for IL-2 in the CNS have been suggested. In addition to the spleen, AVP might also mediate some IL-2 effects centrally. In the present study, we evaluated the effect of IL-2 on the in vitro release of AVP from the hypothalamus and amygdala. In addition, we used these release systems to study the possible involvement of NO-mediated signaling in AVP release, based on the reported detection of nitric oxide synthase (NOS) in the hypothalamus and amygdala. IL-2 rapidly stimulates AVP release in both regions, in a calcium- and dose-dependent manner. In addition, nitroprusside also induces AVP release. Norepinephrine also induces AVP release from both the hypothalamus, as well as the amygdala. The norepinephrine-induced AVP release is antagonized by phentolamine, but not by propranolol, suggesting an alpha-adrenergic receptor-mediated AVP response in both brain regions. The IL-2- and acetylcholine-induced AVP release is antagonized by Ng-methyl-L-arginine, indicating a role for NO in this AVP release. Ng-methyl-L-arginine does not affect the norepinephrine-induced AVP release. A stimulatory effect of IL-2 on hypothalamic CRF release and plasma ACTH has already been reported. Our results suggest that in addition to CRF, AVP may also mediate the IL-2 stimulation of ACTH secretion. These data further suggest that in addition to the hypothalamus, the amygdala may also play a role in the bidirectional communication between neuroendocrine and immune systems. Understanding the mode of interaction between IL-2 with AVP could clarify the pathophysiologic or toxic effects of high brain levels of IL-2.
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PMID:IL-2 induces vasopressin release from the hypothalamus and the amygdala: role of nitric oxide-mediated signaling. 752 33

One of the most central events during lymphocyte activation is the synthesis and release of IL-2. IL-2 induces the synthesis and expression of the IL-2 receptor alpha-chain (IL-2R) on the lymphocyte as well as the release of a truncated form of IL-2R (sIL-2R). The two proteins are identical except for the absence of the transmembrane and intracellular part on sIL-2R. We have in an in vitro model investigated the influence of certain compounds, affecting different parts of the proliferative response, on the release and expression of IL-2R. We found the generation of the two molecules to have different sensitivity to blocking of protein synthesis, glycosylation, microtubular assembly and proteolytic activity. However, blocking of intracellular transport from Golgi to the endoplasmic reticulum, disassembly of actin filaments and disturbances in the intracellular sodium/calcium balance had identical effects on expression and release of the respective IL-2R. These findings indicate a more complex and specific mechanism behind the generation of sIL-2R than simply by shedding through the action of proteases on the membrane-bound IL-2R.
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PMID:Influence of compounds affecting synthesis, modification and transport of proteins on the expression and release of interleukin-2 receptor. 753 4

Virus free supernatants (VFS) obtained by ultracentrifugation of homogenates of African swine fever (ASF) virus infected cultures inhibited the proliferative response and the expression in peripheral blood mononuclear cells of two activation molecules, the IL-2 receptor (IL-2R) and the swine MHC class II antigens (SLA II), induced by several stimuli (lectins, PMA plus the calcium ionophore A23187 or specific antigen). This inhibition was time dependent: no effect was seen on IL-2R expression when VFS was added after 48 h, when the expression of this molecule reached its maximum. However at this time the proliferative response was still inhibited. The presence of VFS in the cultures was necessary to inhibit both the IL-2R expression and the proliferation of cells. In these conditions the addition of exogenous IL-2 to the cultures failed to restore the IL-2R expression and the proliferation shown by control stimulated cells. Furthermore, the IL-2 activity found in supernatants from cell cultures stimulated with Con A in the presence of VFS was even higher than in cultures stimulated without VFS. The inhibition observed suggests an important impairment of host immunocompetence in ASF infected swine.
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PMID:Inhibition of IL-2R and SLA class II expression on stimulated lymphocytes by a suppressor activity found in homogenates of African swine fever virus infected cultures. 761 79

Leflunomide, a novel immunosuppressive drug, is able to prevent and reverse allograft and xenograft rejection in rodents, dogs, and monkeys. It is also effective in the treatment of several rodent models of arthritis and autoimmune disease. In vitro studies indicate that leflunomide is capable of inhibiting anti-CD3- and interleukin-2 (IL-2)-stimulated T cell proliferation. However, the biochemical mechanism for the inhibitory activity of leflunomide has not been elucidated. In this study, we characterized the inhibitory effects of leflunomide on Src family (p56lck and p59fyn)-mediated protein tyrosine phosphorylation. Leflunomide was able to inhibit p59fyn and p56lck activity in in vitro tyrosine kinase assays. The IC50 values for p59fyn (immunoprecipitated from either Jurkat or CTLL-4 cell lysate) autophosphorylation and phosphorylation of the exogenous substrate, histone 2B, were 125-175 and 22-40 microM respectively, while the IC50 values for p56lck (immunoprecipitated from Jurkat cell lysates) autophosphorylation and phosphorylation of histone 2B were 160 and 65 microM respectively. We also demonstrated the ability of leflunomide to inhibit protein tyrosine phosphorylation induced by anti-CD3 monoclonal antibody in Jurkat cells. The IC50 values for total intracellular tyrosine phosphorylation ranged from 5 to 45 microM, with the IC50 values for the zeta chain and phospholipase C isoform gamma 1 being 35 and 44 microM respectively. Leflunomide also inhibited Ca2+ mobilization in Jurkat cells stimulated by anti-CD3 antibody but not in those stimulated by ionomycin. Distal events of anti-CD3 monoclonal antibody stimulation, namely, IL-2 production and IL-2 receptor expression on human T lymphocytes, were also inhibited by leflunomide. Finally, tyrosine phosphorylation in CTLL-4 cells stimulated by IL-2 was also inhibited by leflunomide. These data collectively demonstrate the ability of leflunomide to inhibit tyrosine kinase activity in vitro, and suggest that inhibition of tyrosine phosphorylation events may be the mechanism by which leflunomide functions as an immunosuppressive agent.
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PMID:Inhibition of protein tyrosine phosphorylation in T cells by a novel immunosuppressive agent, leflunomide. 775 80

Interleukin-2 (IL-2)-like immunoreactivity and IL-2 receptor immunoreactivity have been reported in different brain regions, under normal and pathophysiological conditions. IL-2 stimulates hypothalamic corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) release and that of pituitary adrenocorticotropin. The amygdala, known to contain high levels of CRF, is involved in stress-related reactions, including regulation of the hypothalamo-pituitary-adrenal axis. IL-2 will release AVP from both the hypothalamus and the amygdala, which further supports a role for cytokine effects in the amygdala in neuroimmune interactions. In the present study, we compared the effects of IL-2, acetylcholine and norepinephrine on the in vitro release of CRF from the amygdala or hypothalamus. In addition, we used these release systems to evaluate the possible involvement of nitric oxide (NO)-mediated signaling in CRF release. IL-2 stimulates CRF release in both regions, in a calcium- and dose-dependent manner. Nitroprusside, an NO generator, also induces CRF release. This IL-2-induced CRF release is antagonized by Ng-methyl-L-arginine and hemoglobin, known NO antagonists. Finally, norepinephrine and acetylcholine induce CRF release. The norepinephrine-induced CRF release is antagonized by phentolamine and propanolol and the acetylcholine-induced release by atropine and mecamylamine, which suggests the involvement of both alpha and beta adrenergic receptors and both muscarinic and nicotinic receptors. The acetylcholine-induced CRF release is antagonized by Ng-methyl-L-arginine, but the norepinephrine-induced response is not. These data support the suggestion that the amygdala may participate in communications between the neuroendocrine and immune systems.
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PMID:Interleukin-2 (IL-2) induces corticotropin-releasing factor (CRF) release from the amygdala and involves a nitric oxide-mediated signaling; comparison with the hypothalamic response. 785 99

A role for CD26 surface antigen (Ag) in both CD3- and CD2-mediated T cell activation has been previously demonstrated. To analyze the functional role of CD26 in the CD3- and CD2-induced activation pathways of cord T cells, which represent the most reliable source of Ag-unprimed T cells, we employed a newly developed anti-CD26 monoclonal antibody, termed anti-1F7, anti-CD3 and anti-CD2 in activating T lymphocytes. The results showed that CD26 Ag is expressed on the surface of almost all resting cord T cells and that its fluorescence intensity is enhanced by activation. The binding of anti-1F7 induced a decrease in CD26 membrane expression, with no detectable effect on the surface expression of other cord T cell-related molecules. Moreover, the modulation of CD26 resulted in an increase in anti-CD3-mediated cord T cell activation through an enhancement in intracellular calcium levels, IL-2 receptor expression, and IL-2 synthesis, whereas it had no effect on cord T cell activation induced by anti-CD2 or anti-CD2 plus exogenous IL-2. The fact that the selective involvement of CD26 in the activation pathway triggered by anti-CD3, but not anti-CD2, could be reversed by prior stimulation of cord T cells with anti-CD3 suggests that this functional feature, which resembles that of mature thymocytes, may be linked to the Ag-unprimed cell phenotype of cord T lymphocytes.
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PMID:Activation of cord T lymphocytes. IV. Analysis of surface expression and functional role of 1F7 (CD26) molecule. 790 98

To determine a role of protein kinase C (PKC) isozymes in lymphocyte activation, human peripheral blood mononuclear cells were activated with 12-deoxyphorbol-13-O-phenylacetate (dPP; an agonist of both calcium-dependent and calcium-independent PKC isozymes), thymeleatoxin (TX; an activator of calcium-dependent PKC alpha, beta, and gamma), and 12-deoxyphorbol-13-O-phenylacetate 20 acetate (dPPA; an activator of PKC beta 1 isozyme) and examined for DNA synthesis, lymphocyte proliferation, interleukin-2 (IL-2) production, expression of IL-2 receptor alpha and beta chains on CD3+, CD4+, and CD8+ T lymphocytes and CD20+ B lymphocytes, and translocation of PKC beta isozyme from cytosol to membrane fraction. The results show that dPPA activates lymphocytes by inducing the above changes in a manner analogous to that of dPP, TX, and phorbol myristate acetate. These data suggest that PKC beta 1 is involved in the activation of human peripheral blood T and B lymphocytes.
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PMID:12-Deoxyphorbol-13-O-phenylacetate 20 acetate [an agonist of protein kinase C beta 1 (PKC beta 1)] induces DNA synthesis, interleukin-2 (IL-2) production, IL-2 receptor alpha-chain (CD25) and beta-chain (CD122) expression, and translocation of PKC beta isozyme in human peripheral blood lymphocytes: evidence for a role of PKC beta 1 in human T cell activation. 792 99

The immunoregulatory action of saikosaponin-d (SSd), which was isolated from the root of Bupleurum falcatum L. and has a steroid-like structure, was examined on splenic T lymphocytes of C57BL/6 mice. SSd displayed a definite action in vitro to bidirectionally control the growth response of T lymphocytes stimulated by concanavalin A, anti-CD3 monoclonal antibody, and calcium ionophore A23187 plus phorbol 12-myristate 13-acetate. Low concentrations (1-3 micrograms/ml) of SSd upregulated the responses to suboptimum stimuli of agonists, particularly during the relatively late stage of the responses, whereas it downregulated the responses to supraoptimal stimuli. Under appropriate experimental conditions, SSd promoted interleukin-2 (IL-2) production and IL-2 receptor expression. It also accelerated c-fos gene transcription, but it did not modulate the level of tyrosine phosphorylation of cellular proteins. We concluded from these results that SSd uniquely modulates T lymphocyte function and that at least one target of the action of SSd is located at or before the step of c-fos gene transcription and after T-cell receptor/CD3-mediated protein tyrosine kinase activation.
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PMID:Characterization of the immunoregulatory action of saikosaponin-d. 795 39


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