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

Stimulation of T cells by the T-cell receptor (TCR)/CD3 complex results in interleukin-2 (IL-2) synthesis and surface expression of the IL-2 receptor (IL-2R), which in turn drive T-cell proliferation. However, the significance of the requirement of IL-2 in driving T-cell proliferation, when TCR stimulation itself delivers potential mitogenic signals, is unclear. We show that blocking of IL-2 synthesis by Cyclosporin A (CsA) suppressed both the Concanavalin A (Con A)- and phorbol myristate acetate (PMA)/ionomycin-induced proliferation of T cells. The latter is also inhibited by anti-IL-2R. Kinetic studies showed that T-cell proliferation begins to become resistant to CsA inhibition by about 12 h and became largely resistant by 18 h of stimulation. PMA, the protein kinase C activator, enhanced Con A-induced T-cell proliferation if added only within first 12 h of stimulation, and not after that. Given the fact that, in the present study, TCR is downregulated within 2 h of Con A stimulation and T cells entered the S phase of cell cycle by about 18 h of stimulation, the above results suggest that TCR stimulation provides the initial trigger to the resting T cells, which allows the cells to traverse the first two third portions of G1 phase of cell cycle and become proliferation competent. IL-2 action begins afterward, delivering the actual proliferation signal(s), allowing the cells to traverse the rest of G1 phase and enter the S phase of the cell cycle.
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PMID:Relative roles of T-cell receptor ligands and interleukin-2 in driving T-cell proliferation. 1058 Sep 99

Cyclosporine (CsA) has been implicated in both acute and chronic graft dysfunction. The addition of humanized IL-2 receptor antibody daclizumab (DZB) to CsA-based immunosuppression decreases the rate of acute renal transplant rejection. Therefore, 45 patients were evaluated in an immunosuppressive protocol that included DZB, mycophenolate mofetil (MMF), and steroids without CsA. This was a prospective, nonrandomized, open-label trial of the efficacy and safety of the treatment. DZB was given intravenously at 2 mg/kg before transplantation and then at 1 mg/kg every 2 wk for four doses, MMF was given orally at 3 g/d, and methylprednisolone/prednisone was given at 7 mg/kg per day and tapered to 15 mg/d at 6 mo. CsA was added to the regimen when patients developed acute rejection episodes or adverse effects to steroids or MMF; 49% of patients were spared CsA maintenance. Patients without CsA had lower serum creatinine at 6 mo and needed fewer medications to control BP. Incidence of biopsyproven rejections was 31% and occurred early (median, 10 d). These rejection episodes occurred earlier in cadaver transplants (median, 7 d) and later in living donor transplants (median, 62 days). Acute rejections occurred at a higher frequency (46% versus 34%) and earlier (6.5 versus 15 d) in patients with delayed graft function compared with patients without delayed graft function. Most of the rejections were moderate and easily reversible. The actuarial 1-yr graft survival was 95% with 100% patient survival.
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PMID:Avoidance of cyclosporine in renal transplantation: effects of daclizumab, mycophenolate mofetil, and steroids. 1100 26

A 36-year-old woman was referred to our hospital because of leukocytosis in June 2000, and was admitted to our hospital and diagnosed as having adult T-cell leukemia/lymphoma (ATL; acute type). Complete remission was achieved with eight courses of CHOP therapy, but ATL relapsed and she was readmitted to our hospital in September 2001. Laboratory examination showed elevated levels of serum LDH and soluble IL-2 receptor, and hypercalcemia. CT examinations showed swelling of the abdominal lymph nodes and hepatosplenomegaly. CHOP therapy improved the symptoms, but recrudescence soon occurred. After two courses of salvage therapy which resulted in no remission, the patient received an allogeneic peripheral blood stem cell transplant (allo-PBSCT) from her HLA-matched sibling donor after preconditioning with BU + CY in January 31, 2002. Cyclosporin A (CsA) and short-term MTX were used to prevent GVHD. Bone marrow engraftment was prompt and acute GVHD was not found. Two months later, recurrence was seen in the form of subcutaneous tumors, but the tumors spontaneously disappeared following CsA withdrawal. At the time of writing, eight months after the transplant, remission has been maintained. A graft-versus-leukemia (GVL) effect may have been the curative action in this case.
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PMID:[Cyclosporin A withdrawal causes spontaneous remission of recurrent subcutaneous tumors after allogeneic peripheral blood stem cell transplantation for adult T-cell leukemia/lymphoma]. 1269 82

Graft rejections as well as tolerance are true representation of the specificity, sophistication and redundancy of an elegantly and meticulously designed immune system. Tolerance is in a way similar to the process of self-recognition where lymphoid clones, during development, baring self-reactive receptor are eliminated or rendered in active by "clonal deletion" leading to a state of accommodation and acceptance (anergic). On the other hand, both acute and chronic rejections are manifestation of the purpose of existence of the immune system, which is to defend the host against foreign invaders. Thus, in order to treat (control) graft rejection it is necessary to determine and understand the steps leading to recognition, stimulation, activation, and amplification of the immune system. The first step leading to the initiation of the immune system cascade is recognition. Which can either be direct where donor antigens of the major histocompatibility complex (MHC) expressed on the donor cells (passenger leukocytes) or tissues are recognised by the host immune system. The direct recognition pathway initiates acute graft rejection. Alternatively processed donor MHC peptides presented by the recipient antigen presenting cells (APC) initiate the indirect pathway of immune response, which is as important as the direct recognition especially in chronic rejection. Recognition is followed by the ligation of a series of adhesion molecules starting with an antigen to its specific T-cell receptor (TCR)/cluster of differentiation (CD) complex, expressed on the surface of the T cell. In order for the activation to precede additional costimulatory signals, such as ligation of the CD28/B7, CD4/HLA class II and CD/HLA class I antigens are required. The activation process is accompanied by an increase of cytokines production such as interleukin (IL)-2, IL-12, interferon (INF) and tumour necrosis factor (TNF) by the primed T cell. The complexity and the polymorphic nature of the immune system have necessitated designing agents that inhibit the immune system at different levels. Cyclosporine and Tacrolimus, collectively known as calcineurin inhibitors, seems to act on the IL-2 by inhibiting its production thus leading to a decrease in the proliferation of the activated lymphocyte. Rapamycin, which is similar to Tacrolimus, inhibits graft rejection by blocking IL-2 activation and phosphorylation of 70 S6 kinase thus inhibiting the progression of T-cell from G to S phase. While Cellcept (MMF) reduce the proliferation of T cell by inhibiting purine synthesis and by its action on ionosine monophosphate dehydrogenase. Anti-lymphocyte antibodies (ATG) deplete circulating lymphocytes while selective monoclonal antibodies are directed against IL-2 receptor thus reducing the rate of proliferation of activated T cells. Recently, antibodies to the CD40/CD40 ligand have been shown to induce long-term graft survival with the inhibition of the Th1 cytokines (INF), IL-2 and IL-12 and upregulating the Th2 cytokines IL-4 and IL-10. Lastly graft rejection can be reduced by blockade of the B7/CD28 costimulation pathway with the fusion protein CTLA-4Ig. With the availability of such potent and diverse agents it is now possible to develop multi drug regiments that can depress the immune system at the different steps of the activation cascade, with minimal side effects, thus improving graft and patient survival rates.
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PMID:The mosaic of immunosuppressive drugs. 1283 79

Human T-cell leukemia virus type 1 (HTLV-1) but not HTLV-2 is associated with adult T-cell leukemia. We found that HTLV-2 Tax2 protein stimulated reporter gene expression regulated by the interleukin (IL)-2 promoter through the nuclear factor of activated T cells (NFAT) in a human T-cell line (Jurkat). However, the activity of HTLV-1 Tax1 was minimal in this system. T-cell lines immortalized by HTLV-2 but not HTLV-1 constitutively exhibited activated NFAT in the nucleus and constitutively expressed IL-2 mRNA. Cyclosporine A, an inhibitor of NFAT activation, abrogated the induction of IL-2 mRNA in HTLV-2-immortalized T-cell lines and concomitantly inhibited cell growth. This growth inhibition was rescued by the addition of IL-2 to the culture. Furthermore, anti-IL-2 receptor antibodies significantly reduced the proliferation of HTLV-2-infected T-cell lines but not that of HTLV-1-infected cells. Our results suggest that Tax2 activates an IL-2 autocrine loop mediated through NFAT that supports the growth of HTLV-2-infected cells under low-IL-2 conditions. This mechanism would be especially important in vivo, where this autocrine mechanism establishes a nonleukemogenic life-long HTLV-2 infection. The results also suggest that differences in long-term cytokine production between HTLV-1 and HTLV-2 infection are another factor for the differences in pathogenesis.
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PMID:Aberrant activation of the interleukin-2 autocrine loop through the nuclear factor of activated T cells by nonleukemogenic human T-cell leukemia virus type 2 but not by leukemogenic type 1 virus. 1614 Jul 68

We have proposed in vitro immunotoxicology screening systems utilizing cDNA probes to monitor alterations in cytokine expression in defined cell populations. In this study we compared responses observed following in vitro exposure with responses in cells obtained ex vivo. Peritoneal macrophages and splenic lymphocytes were cultured from C3H mice or PVG rats and exposed to graded concentrations of the immunomodulators, biostim, cyclosporin A, azathioprine or tributyltin oxide (TBTO). Biostim (1 mug/ml) induced the expression of cytokine mRNAs in peritoneal macrophage cultures and induced a similar spectrum of cytokine expression in macrophages following administration to mice (100 mug/kg ip). Cyclosporin A (1 mug/ml) totally inhibited the expression of IL-2 mRNA in murine mixed lymphocyte cultures and induced a 40% inhibition of IL-2 mRNA in splenocytes isolated from mice repetitively exposed (5 x 100 mg/kg over 10 days). Azathioprine (10 mug/ml) inhibited the expression of all mRNAs in rat lymphocyte cultures and inhibited both IL-2 mRNA and actin expression in thymocytes isolated from PVG rats (2 mg/kg/day for 28 days). TBTO (10 nm) induced a 25% inhibition of an early peak of IL-2 receptor mRNA expression within mixed lymphocyte cultures and induced a 10% inhibition of expression of IL-2 receptor mRNA within mixed lymphocyte cultures from rats exposed to 50 mg/kg/day for 28 days. Our results demonstrate that appropriate batteries of in vitro tests can identify the four immunomodulatory chemicals described here. Observations made in vitro using molecular biological analysis have been shown to correlate with parallel ex vivo analysis.
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PMID:Altered gene expression in immunotoxicology screening in vitro: Comparison with ex vivo analysis. 2069 3


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