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

We performed a placebo-controlled study to evaluate the effects of immunomodulatory treatment with thalidomide on HIV levels, TNF-alpha levels, and immune status of 31 HIV-infected individuals, after temporary suppression of viral replication with antiretroviral drugs. Treatment with a combination of zidovudine and lamivudine (ZDV/LMV) for 14 days resulted in a median decline in plasma viremia of 1.94 log10 RNA equivalents/ml. After discontinuation of ZDV/LMV, thalidomide therapy (200 mg/day for 4 weeks) did not retard the prompt return of HIV titers to the pretreatment levels, and had no effect on plasma levels of TNF-alpha. In contrast, thalidomide treatment resulted in significant immune stimulation. We observed increased levels of plasma soluble IL-2 receptor, soluble CD8 antigen, and IL-12 (p < 0.01 for all parameters), as well as increased cutaneous delayed-type hypersensitivity reactions to recall antigens (p < 0.01) in thalidomide-treated patients. These changes were associated with a median increase in HIV titer of 0.2 log10 RNA equivalents/ml in the thalidomide-treated group (p < 0.05), which resolved after stopping the drug. Further studies were performed in vitro to elucidate the mechanism of thalidomide-induced immune stimulation. When purified T cells from HIV-infected individuals were stimulated by immobilized anti-CD3 in the presence of thalidomide, a costimulatory effect of the drug was observed, resulting in increased production of IL-2 and IFN-gamma, and increased T cell-proliferative responses. Further experiments showed that thalidomide increased IL-12 production by antigen-presenting cells in a T cell-dependent manner. Our findings suggest a potential application for thalidomide as a novel immune adjuvant in HIV disease.
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PMID:Thalidomide stimulates T cell responses and interleukin 12 production in HIV-infected patients. 1048 Jun 30

This study shows that naive CD8 T cells can acquire characteristics of memory T cells in the absence of stimulation with specific Ag simply by the process of homeostatic proliferation under lymphopenic conditions. This Ag-independent T cell differentiation pathway did not result in up-regulation of early activation markers (CD69, CD25, CD71), but expression of several memory markers (CD44, CD122, Ly6C) increased progressively with successive divisions. These markers were then stably expressed, and these cells also became more responsive functionally to specific Ag. Thus, all "memory" phenotype T cells in an individual may not be true Ag-experienced cells and may include naive cells masquerading as memory cells. These findings are specially relevant in cases of disease or treatment-induced lymphopenia such as in HIV-infected individuals or transplant recipients. In addition, this study may have implications for autoimmunity because homeostatic proliferation of naive T cells requires interaction with self peptide plus MHC molecules.
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PMID:Cutting edge: naive T cells masquerading as memory cells. 1092 49

Evaluation of cytokine gene expression following in vitro stimulation is one means of examining the dysregulation of the immune system in human immunodeficiency virus (HIV) infection. We have assessed differences in the immune status of non-HIV-infected (HIV-) and HIV-infected (HIV+) individuals by evaluating the kinetics of the expression of cytokine genes. We compared detailed time courses of cytokine mRNA expression in HIV- and HIV+ peripheral blood mononuclear cells (PBMC) and found that there is a significant shift (P<0.01) for all cytokines examined (interleukin 2 [IL-2], IL-6, IL-10, gamma interferon, and tumor necrosis factor alpha [TNF-alpha]) to an earlier time of mean peak mRNA expression by HIV+ PBMC (between 4 and 8 h) compared to HIV- PBMC (8 h) in response to either phytohemagglutinin (PHA) or anti-CD3 stimulation. Additional studies showed that although PHA-stimulated HIV+ PBMC showed decreased median IL-2, IL-4, and TNF-alpha mRNA levels, they typically demonstrated more rapid kinetics (increased mean 4-h/24-h cytokine mRNA ratios), with significant differences for IL-4 (P<0.05) and TNF-alpha (P<0.005), compared to HIV- PBMC. The use of fresh or frozen cells gave comparable cytokine mRNA data; however, the secretion of some cytokine proteins (IL-2 receptor, IL-10, and TNF-alpha) appeared to be reduced in HIV+ PBMC that had been frozen and thawed. Our studies demonstrate that the kinetics of cytokine gene expression can reveal additional dysregulation of the immune system in HIV infection, suggesting that PBMC of HIV-infected persons exist in an activated state in vivo that permits them to express cytokine genes more rapidly than a normal PBMC.
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PMID:Cytokine gene expression occurs more rapidly in stimulated peripheral blood mononuclear cells from human immunodeficiency virus-infected persons. 1097 52

This work shows the presence of structural and physical analogies between some precise sites of the trimeric ectodomain of the transmembrane envelope glycoproteins of the HIV, SIV and FIV viruses and some precise sites of the interleukin 2 of the corresponding infected species (man, monkey, cat, respectively). In all the cases examined, the ectodomains of GP41 (HIV-SIV) and GP36 (FIV), because of their trimeric structure, place in the same spatial configuration the same amino acids clusters as the IL-2 amino acids clusters interacting with two, or even three, of the alpha, beta and gamma subunits of the IL-2 receptor. The molecular mimicry identified between the viral transmembrane glycoprotein and IL-2 is probably most useful for the virus and seems to be specific of each species; it is presumably due to a strategy common to the retroviruses associated with AIDS (HIV, SIV, FIV).
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PMID:Molecular mimicry between the trimeric ectodomain of the transmembrane protein of immunosuppressive lentiviruses (HIV-SIV-FIV) and interleukin 2. 1114 25

Immune cells secrete a variety of cytokines that have a profoundly significant influence on the immune system. For example, cytokines secreted by T-helper cells have a role in cellular immune response (Th1 cytokines) and in antibody production (Th2 cytokines). Interleukin 2 (IL-2) is used therapeutically for immune modulation, most specifically in cancer therapy. The following report describes the mechanisms of IL-2/IL-2 receptor interaction and summarizes the rationale for using IL-2 in HIV-infected patients and briefly describes recent and ongoing clinical trails using IL-2 in HIV/AIDS disease (intravenous IL-2 therapy and subcutaneous IL-2 therapy). In one study of patients with moderate stage HIV disease, subjects taking a maximum tolerated dose of IL-2 at 12 to 15 MIU/day demonstrated durable increases in CD4 counts and a near normal return in value. Relative to the published reports, low circulating CD4 counts and high HIV viral burden appeared to be independent determinants of a poor response to IL-2. However, aggressive combination therapy with IL-2 and highly active anti-retroviral therapy (HAART)(e.g., ACTG 328) holds promise for an improved immune restorative response even in patients with advanced disease.
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PMID:Interleukin-2 therapy in HIV infection. 1136 33

In an interview, Kendall A. Smith, M.D., whose laboratory identified the IL-2 molecule and the IL-2 receptor, discusses a current study on administering low, daily doses of IL-2 to HIV patients who are also on HAART. One purpose of the study is to see if IL-2 increases the recovery of CD4 cells over an extended period. The second purpose is to see if a patient's immune system might be able to control the virus when HAART is interrupted, but IL-2 treatment is continued. The study results are described. Dr. Smith also discusses the history of IL-2 and other trials currently studying IL-2.
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PMID:IL-2 low dose and treatment interruption: interview with Kendall A. Smith. Interview by John S. James. 1136 19

To characterize the immunological effects of intermittent IL-2 therapy, which leads to selective increases in CD4+ T lymphocytes in HIV-infected patients, 11 patients underwent extensive immunological evaluation. While IL-2 induced changes in both CD4+ and CD8+ cell number acutely, only CD4+ cells showed sustained increases following discontinuation of IL-2. Transient increases in expression of the activation markers CD38 and HLA-DR were seen on both CD4+ and CD8+ cells, but CD25 (a chain of the IL-2 receptor) increased exclusively on CD4+ cells. This increase in CD25 expression was sustained for months following discontinuation of IL-2, and was seen in naive as well as memory cells. IL-2 induced cell proliferation, but tachyphylaxis to these proliferative effects developed after 1 week despite continued IL-2 administration. It thus appears that sustained CD25 expression selectively on CD4+ cells is a critical component of the immunological response to IL-2, and that intermittent administration of IL-2 is necessary to overcome the tachyphylaxis to IL-2-induced proliferation.
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PMID:Interleukin-2 induced immune effects in human immunodeficiency virus-infected patients receiving intermittent interleukin-2 immunotherapy. 1146 92

The interleukin (IL)-2 receptor has proved an attractive target for T cell-directed therapies. Agents including monoclonal antibodies, single-chain antibody immunoconjugates, radioimmunoconjugates, and, most recently, ligand fusion toxins have demonstrated activity in vitro and in clinical trials in both hematologic malignancies and diseases characterized by proliferation of activated T cells, such as graft-versus-host disease. DAB389IL-2 (ONTAK) is a ligand fusion toxin consisting of the full-length sequence of the IL-2 gene genetically fused to the enzymatically active and translocating domains of diphtheria toxin. DAB389IL-2 and its predecessor, DAB486IL-2, have demonstrated activity in a variety of diseases, including cutaneous T cell lymphoma (CTCL), psoriasis, rheumatoid arthritis, and HIV infection. Further clinical development of IL-2 fusion toxins in CTCL and other hematopoietic malignancies is predicated on identification of the high-affinity IL-2 receptor complex on the malignant cells and on a better understanding of the biological determinants of cytotoxicity of these molecules in vivo.
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PMID:Interleukin-2 fusion toxin: targeted therapy for cutaneous T cell lymphoma. 1159 70

Fusion proteins are recombinant molecules that combine a targeting mechanism to a cytocidal moiety. DAB(389)IL-2 (denileukin diftitox; ONTAK), with a unique mechanism of action, is the first genetically constructed fusion protein to reach the clinic. In this molecule, the interleukin-2 (IL-2) gene is genetically fused to the enzymatically active and translocating domains of diphtheria toxin. DAB(389)IL-2 is internalized into IL-2 receptor-bearing cells by endocytosis. The ADP-ribosyltransferase activity of diphtheria toxin is cleaved in the endosome and is translocated into the cytosol where it inhibits protein synthesis, leading to apoptosis. DAB(389)IL-2 and its predecessor, DAB(486)IL-2, have shown clinical activity in a variety of diseases, including B-cell non-Hodgkin's lymphoma, cutaneous T-cell lymphoma (CTCL), Hodgkin's disease, psoriasis, rheumatoid arthritis, and HIV infection. The highest response rates were observed in CTCL, and this became the focus of clinical trials leading to its subsequent approval by the United States Food and Drug Administration for this disease. The potential applications of DAB(389)IL-2 in lymphomas are reviewed.
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PMID:DAB(389)IL-2 (ONTAK): a novel fusion toxin therapy for lymphoma. 1170 18

IL-16 is a multi-functional cytokine that uses CD4 as a receptor to signal diverse biological activities by target cells including T-lymphocytes, monocytes and eosinophils. IL-16 has been shown to repress HIV-1 infection in lymphocytes and monocytic cells and it is active against both laboratory and naturally acquired virus isolates. In lymphocytes, the repressive effect of IL-16 occurs at the level of virus transcription, while it appears to inhibit viral entry in monocytic cells. Clinical studies comparing serum IL-16 levels with the state of HIV-1 disease suggest that this cytokine is a functionally significant endogenous antiviral factor. The antiviral activity of IL-16 may be of therapeutic benefit in HIV/AIDS but its greatest potential is for immune reconstitution. Stimulation of CD4+ T-cells with IL-16 primes cells to respond to IL-2, by upregulating the expression of IL-2 receptor p75 (CD25). Co-treatment of peripheral blood mononuclear cells (PBMC) with IL-16 plus IL-2 (or IL-15) in vitro selectively expands the population of CD4+ T-cells. Clinical trials of recombinant IL-2 have already shown promise in HIV/AIDS. In combination with IL-16, the beneficial effects of IL-2 may be augmented and specifically targeted to CD4+ T-cells. Thus, IL-16 shows considerable promise as an agent for the biological therapy of HIV/AIDS.
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PMID:Prospects for IL-16 in the treatment of AIDS. 1172 16


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