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

One mechanism proposed to play a role in T-cell depletion in human immunodeficiency virus (HIV) infection is apoptosis (activation-induced cell death). We assessed whether apoptosis is related to activation of T cells in vivo and its possible triggers. DNA was extracted from peripheral blood mononuclear cells (PBMC) taken from 16 vertically HIV-infected children and 9 HIV-negative children born to HIV-positive mothers (controls) and tested by agarose gel electrophoresis for the presence of DNA fragments specific for apoptosis. Signs of apoptosis were found on in vitro culture of PBMC from 12 of 16 HIV-infected children, but not in PBMC from the nine controls. Eleven of the 12 HIV-infected children with apoptosis showed an elevated (> 15%) proportion of CD3+/HLA-DR+ cells. This was due to an increased proportion of CD8+/HLA-DR+ cells, as shown in 7 of 7 further tested patients. In none of the probands an increased (> 5%) proportion of IL-2 receptor expressing CD3+ cells was found. T cells undergoing apoptosis were preferentially of the CD8+ phenotype. Expansion of circulating CD8+/interleukin-2 receptor (IL-2R)-/HLA-DR+ T cells is known to occur during active infection with herpes viruses. To investigate the possible role of herpes viral coinfections for apoptosis in HIV infection, we focused on Epstein-Barr virus (EBV) as an example for a herpes virus usually acquired during childhood. In 10 of 12 patients with apoptosis, we found increased levels of EBV genome in PBMC and/or tissues, indicating active EBV replication. By contrast, no increased burden of EBV was found in the four HIV-infected patients without apoptosis or in the controls. Our data indicate that in children the occurrence of apoptosis in HIV infection is closely related to activation of CD8+ T cells. Furthermore, primoinfection with or reactivation of herpes viruses, such as EBV, may substantially contribute to such T-cell activation and the ensuing apoptosis. Additional studies are warranted to evaluate the contribution of herpes virus-triggered apoptosis to the T-cell loss leading to the acquired immunodeficiency syndrome.
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PMID:T-cell death by apoptosis in vertically human immunodeficiency virus-infected children coincides with expansion of CD8+/interleukin-2 receptor-/HLA-DR+ T cells: sign of a possible role for herpes viruses as cofactors? 763 48

The intravenous injection of mice with lymphocytic choriomeningitis virus (LCMV) induces a rapid and long-lasting immunodeficiency. T lymphocytes from 7-day-infected mice do not proliferate in vitro in response to ConA stimulation, do not produce IL-2 but display high affinity IL-2 receptors on their membrane. The non-coordinated regulation of these genes suggested that other cytokine-encoding genes may also be affected in their regulation. We have thus analyzed the expression of the genes encoding different cytokines transcribed during spleen cell activation by ConA. The genes encoding T lymphocyte-derived cytokines can be classified in three groups: the genes expressed similarly by normal and LCMV-cells (the p55 and the p75 chains of the IL-2 receptor [1]), the genes under expressed in LCMV-cells (IL-2, IL-3, IL-4 and IL-5) and the genes over expressed by these cells (GM-CSF and IFN-gamma). These results show that the viral infection has provoked a profound alteration of the overall regulation of the genetic program that follows T lymphocyte activation. Since T cell activation depends strictly on accessory cell-derived cytokines, we measured the level of transcription of IL-1, IL-6 and TNF-alpha; and our data show that the expression of these genes is equivalent in normal cells and in cells from LCMV-infected mice.
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PMID:Altered cytokine genes expression by conA-activated spleen cells from mice infected by lymphocytic choriomeningitis virus. 768 35

Human immunodeficiency virus (HIV-1) tat, a trans-activator of the HIV long terminal repeat, is essential for HIV replication and causes inhibition of antigen-mediated T cell proliferation. To understand the mechanism of inhibition of T cell proliferation, we have investigated the regulation of IL-2 production and its receptor expression on a human CD4+ T lymphoid cell line (H9) transfected with HIV-1 tat gene. When cells were activated by mitogens, as compared to control cells, a significant decrease in both IL-2 mRNA and protein was observed in tat-transfected cells. Similarly, mitogen-induced IL-2R alpha and IL-2R beta mRNA and surface expression of IL-2R alpha and IL-2R beta chains were also significantly decreased in tat-transfected cells compared to control cells. Only IL-2 receptor density was decreased; the affinity of the ligand for the receptor appeared to be unchanged. In contrast to our previous studies with B-lymphoblastoid cell line (Puri RK and Aggarwal BB: Cancer Res 1992; 52:3787-3790), IL-4R expression was unaltered by HIV tat transfection in the H9 T cell line, indicating a cell type-specific phenomenon. Owing to the central role of IL-2 immunoregulation, our data suggest that immunosuppressive effects of HIV-1 tat may be mediated at least in part through the inhibition of both IL-2 production and IL-2 receptor expression.
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PMID:Constitutive expression of human immunodeficiency virus type 1 tat gene inhibits interleukin 2 and interleukin 2 receptor expression in a human CD4+ T lymphoid (H9) cell line. 773 94

By using ELISA and assay of MTT participating in IL-6 dependent cell clone. The authors measured the circulating levels of soluble IL-2 receptor (sIL-2R) and IL-6 in patients undergoing hemodialysis (HD). Alterations of the above-mentioned parameters before and after a three-month course of treatment with Chinese drug Epimedium sagittatum on the same HD patients. It is confirmed that in patients with end-stage renal failure (ESRF), sIL-2R level elevated significantly, while IL-6 level decreased apparently (P < 0.01). Furthermore, levels of both sIL-2R and IL-6 could be restored to normal after treatment with Epimedium sagittatum. These findings indicated not only the presence of immunodeficiency in ESRF, but also the effectiveness of regulation with Chinese drug Epimedium sagittatum.
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PMID:[Effect of epimedium sagittatum on soluble IL-2 receptor and IL-6 levels in patients undergoing hemodialysis]. 779 53

A multiple immunodeficiency, involving antibody- and cell-mediated responses in 10 Chinese Shar-Pei (CSP) dogs is described. Abnormal levels of serum IgM and IgA in most cases, and IgG in fewer cases characterized the immunoglobulin deficiencies. Decreased in vitro proliferative responses of pokeweed mitogen (PWM)-stimulated peripheral blood mononuclear cells (PBMC) were found in nine cases. Clinical presentation involved several organ systems and was associated with recurrent infections and malignancy. Sera from affected dogs suppressed PWM-stimulated cell proliferation of affected and normal dogs, but not cultures stimulated with PWM followed by recombinant IL-2 (rIL-2). In vitro supplementation of PBMC cultures with immunomodulatory guanosine analogs (GA) resulted in increased de novo IgG and/or interleukin-6 (IL-6) synthesis. Cells from five immunodeficient dogs showed in vitro evidence of GA- or rIL-2-dependent enhanced immunological responses. Since rIL-2-mediated activation of the IL-2 receptor and GA-mediated immunomodulation are reported to act through protein kinase C (PKC)-independent pathways, it is concluded that the IL-2 receptor is functional in these dogs and that cell activation through alternative pathways may restore immune responses in affected CSP dogs.
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PMID:A primary immunodeficiency syndrome in Shar-Pei dogs. 785 14

In vitro data have demonstrated autologous T-lymphocytes with anti-tumour activity in multiple myeloma (MM). Therefore a phase I/II trial was conducted to study the feasibility, the effect on several immunological parameters, and the tumour response induction of low-dose recombinant interleukin-2 (rIL-2) in MM patients. 18 MM patients of advanced stages in progress, who had failed on standard chemotherapy received 9 x 10(6) IU/m2 rIL-2 twice daily on days 1 and 2 and 0.9 x 10(6) IU/m2 twice daily for 5 subsequent days per week subcutaneously from days 3 to 56 (repeated every 12 weeks until progression). Patients were treated for between 8 and 1086 + d (mean 241 d) without serious side-effects. 6/17 patients experienced tumour response (2/17 objective tumour mass reduction, 4/17 long-lasting stable disease following tumour progression before initiation of rIL-2 treatment). During therapy the number of eosinophils increased 15-fold, CD4+ T lymphocytes were activated as demonstrated by enhanced CD25 antigen expression, and CD56+ NK cells expanded in the peripheral blood. Furthermore, a diminished pre-treatment ratio of CD4+/CD8+ lymphocytes was normalized during rIL-2 treatment. NK cell activity and lymphokine activated killer (LAK) cell activity was significantly enhanced. Endogenous IL-2 production and elevated soluble IL-2 receptor serum concentrations were induced. Low-dose rIL-2 can stimulate immune enhancement in MM despite the characteristic tumour-induced immunodeficiency. The treatment has proven though limited efficacy in advanced MM. Because most of the responders experienced termination of tumour progression rather than tumour regression, rIL-2 maintenance of chemotherapy-induced remissions should be investigated.
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PMID:Low-dose recombinant interleukin-2 therapy in advanced multiple myeloma. 787 83

Interleukin-2 (IL-2) signaling requires the dimerization of the IL-2 receptor beta.(IL-2R beta) and common gamma (gamma c) chains. Mutations of gamma c can result in X-linked severe combined immunodeficiency (XSCID). IL-2, IL-4, IL-7 (whose receptors are known to contain gamma c), and IL-9 (whose receptor is shown here to contain gamma c) induced the tyrosine phosphorylation and activation of the Janus family tyrosine kinases Jak1 and Jak3. Jak1 and Jak3 associated with IL-2R beta and gamma c, respectively; IL-2 induced Jak3-IL-2R beta and increased Jak3-gamma c associations. Truncations of gamma c, and a gamma c, point mutation causing moderate X-linked combined immunodeficiency (XCID), decreased gamma c-Jak3 association. Thus, gamma c mutations in at least some XSCID and XCID patients prevent normal Jak3 activation, suggesting that mutations of Jak3 may result in an XSCID-like phenotype.
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PMID:Interaction of IL-2R beta and gamma c chains with Jak1 and Jak3: implications for XSCID and XCID. 797 58

Soluble proteins of the human immunodeficiency virus (HIV) might play a significant role in the pathogenesis of HIV infection. The addition of synthetic Tat peptides, but not that of the recombinant Nef or Vif protein, inhibited proliferative responses of CD4+ tetanus antigen-specific, exogenous interleukin-2 (IL-2)-independent T-cell clones in a dose-dependent manner. In addition, Tat peptides inhibited the anti-CD3 monoclonal antibody-induced proliferative responses of both purified CD4+ and CD8+ T cells. Tat did not affect proliferative responses induced by phorbol myristate acetate plus ionomycin. The Tat peptides at the concentrations used (0.1 to 3 micrograms/ml) did not affect the viability of the cells as determined by trypan blue exclusion. Treatment of Tat peptides with polyclonal Tat antibodies abrogated the inhibitory effect of Tat. Soluble Tat proteins secreted by HeLa cells transfected with the tat gene also inhibited antigen-induced proliferation of the T-cell clones. Tat inhibited the anti-CD3 monoclonal antibody-induced IL-2 mRNA expression and IL-2 secretion but did not affect IL-2 receptor alpha-chain mRNA or protein expression on peripheral blood T cells. Finally, treatment of T-cell clones with the Tat peptide did not affect the antigen-induced increase in intracellular calcium, hydrolysis of phosphatidyl inositol to inositol trisphosphate, or translocation of protein kinase C from the cytosol to the membrane. These studies demonstrate that the mechanism of the Tat-mediated inhibition of T-cell functions involves a phospholipase C gamma 1-independent pathway.
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PMID:Human immunodeficiency virus Tat induces functional unresponsiveness in T cells. 798 46

Data from a variety of sources suggest that one target cell for levamisole might be the macrophage. Current results reveal that oral levamisole pre-treatment provides elicited peritoneal macrophages with the ability to respond better to ex vivo LPS stimulation, and that levamisole can directly act on LPS-stimulated macrophages in vitro, resulting in enhanced production of IL-1, a key mediator of the immune response. These data offer further biological and immunologic evidence that IL-1 production is indeed enhanced by levamisole. Finally, these phenomena were not confined to macrophages taken from mice given levamisole. Increased IL-1 expression was found to occur for cells treated in vitro with levamisole, demonstrating that there were direct effects by levamisole on LPS-stimulated macrophage cytokine production. IL-1 has been reported to have a number of direct and indirect anti-tumor effects which might be sufficient to provide localized protection against tumor invasion or growth in the adjuvant setting. The findings described above are therefore consistent with suggestions of an increased host response in certain types of cancer due to levamisole treatment, and are also consistent with reports of levamisole's providing a beneficial effect in other cases of immunodeficiency disease. Recent clinical data provided by Janik et al. demonstrate that levamisole administration caused increases in circulating levels of neopterin and soluble IL-2 receptor (sIL-2R). This in vivo result is consistent with in vitro data showing augmented IL-1 induction after levamisole treatment, since neopterin is a marker for macrophage activation and sIL-2R release correlates with IL-2 production and binding after IL-1 activation of T-cells. These data are therefore consistent with the hypothesis that levamisole can induce a macrophage-derived cytokine cascade which may have beneficial effects in host responses to human cancer. It is attractive to speculate that there may be increased cytokine expression in vivo (yet to be confirmed) which might contribute to the added clinical benefit when 5-FU is combined with levamisole. Data from nude mice bearing human tumor xenografts demonstrate improved antitumor responses to 5-FU in combination with levamisole, and it will be interesting to determine whether increased interferon, TNF, or other cytokines can be observed in this model. In addition, the ability of levamisole to increase ICAM-1 expression on certain tumor cell lines may be a mechanism by which similar cells are rendered more sensitive to host effector mechanisms in vivo.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Experimental modulation of IL-1 production and cell surface molecule expression by levamisole. 810 13

Infection with Herpesvirus saimiri, a tumor virus of non-human primates, transformed human CD4+ T cell clones to permanent interleukin (IL)-2-dependent growth without need for restimulation with antigen and accessory cells. The IL-2-dependent proliferation of these cells was dramatically inhibited by soluble anti-CD4 whole antibodies, F(ab')2 and Fab fragments, and also by gp 120 of human immunodeficiency virus. The inhibition was not due to cell death and could be overcome by high concentrations of exogenous IL-2. Cell surface expression of CD4, and to a lesser degree the density of the IL-2 receptor alpha chain, were reduced upon anti-CD4 treatment. After long lasting (> 12 h) incubation with anti-CD4, abundance and activity of CD4-bound p56lck were diminished while the free fraction of p56lck remained unchanged. Since IL-2 binding to its receptor activated only the CD4-bound fraction of p56lck, the IL-2-induced p56lck activity was diminished after long-term CD4 ligation. Taken together, our results suggest a cross talk between CD4- and IL-2 receptor-mediated signaling via p56lck.
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PMID:Engagement of the CD4 receptor inhibits the interleukin-2-dependent proliferation of human T cells transformed by Herpesvirus saimiri. 814 55


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