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)

Even a moderate increase in the cellular cysteine supply elevates the intracellular glutathione (GSH) and glutathione disulfide (GSSG) levels and potentiates immunological functions of lymphocytes in vitro. At low GSSG levels, T cells cannot optimally activate the immunologically important transcription factor NF kappa B, whereas high GSSG levels inhibit the DNA binding activity of NF kappa B. The effects of GSSG are antagonized by reduced thioredoxin (TRX). As the protein tyrosine kinase activities p56lck and p59fyn are activated in intact cells by hydrogen peroxide, they are likely targets for GSSG action. These redox-regulated enzymes trigger signal cascades for NF kappa B activation and transduce signals from the T cell antigen receptor, from CD4 and CD8 molecules, and from the IL-2 receptor beta-chain. The effector phase of cytotoxic T cell responses and IL-2-dependent functions are inhibited even by a partial depletion of the intracellular GSH pool. As signal transduction is facilitated by prooxidant conditions, we propose that the well-known immunological consequences of GSH depletion ultimately may be results of the accompanying GSSG deficiency. As HIV-infected patients and SIV-infected rhesus macaques have, on the average, significantly decreased plasma cyst(e)ine and intracellular GSH levels, we also hypothesize that AIDS may be the consequence of a GSSG deficiency as well.
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PMID:Functions of glutathione and glutathione disulfide in immunology and immunopathology. 795 18

Human intestinal lamina propria T cells have a low expression of the CD45RA antigen and a high expression of the CD45RO antigen. This phenotype is characteristic for memory T cells. In addition, T cells in the effector compartment of the mucosa bear surface antigens that are very rarely found in other sites of the immune system. Intestinal T cells also express functional IL-2 receptors, and IL-2 receptor alpha-chain mRNA, and are able to synthesize high amounts of IL-2. However, other markers of memory T cells, as CD29, are not expressed in high density in the lamina propria, indicating that lamina propria T cells differ from "classical" memory T cells. This is supported by functional studies in nonhuman primates infected rectally with Chlamydia trachomatis that show that lamina propria T cells do not proliferate after stimulation with antigen but rather provide helper function for immunoglobulin synthesis. These findings indicate a specific state of differentiation of lamina propria T cells that is adapted to the specific requirements in the gut. In inflammatory bowel disease (IBD) and in celiac disease, an increase in the number of CD25-positive activated T cells is found in involved mucosa. It has been shown that mucosal T-cell activation induces epithelial cell damage and mucosal transformation. Thus, a T cell-mediated damage may contribute to the pathogenesis of IBD. HIV-infected patients have a decreased number of CD4-positive T cells in the intestinal lamina propria. The number of CD25-positive activated T cells is also significantly decreased in the intestine compared to controls. Correlating with the presence of HIV-infected mononuclear cells in the mucosa, mucosal atrophy with hyporegeneration and enterocyte dysmaturation is observed. HIV might thus cause impairment and depletion of activated regulatory T cells in the intestinal lamina propria, which could lead not only to a breakdown of the mucosal immune barrier, resulting in a variety of opportunistic infections, but also to malabsorption, due to mucosal atrophy or enterocyte dysfunction. These findings indicate a close relationship between mucosal T cells and enterocyte proliferation and maturation.
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PMID:Cell differentiation and proliferation in the gastrointestinal tract with respect to the local immune system. 797 5

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

Previous studies have shown that exogenous IL-2 does not correct the reduction in phytohaemagglutinin (PHA)-induced proliferation of lymphocytes from HIV-1 infected (HIV+) individuals. We investigated the mechanism of this reduction to determine if reduced expression of the complete IL-2 receptor (IL-2R) was responsible. In a series of experiments, PHA-stimulated lymphocytes from a total of 89 HIV- and 93 HIV+ homosexual men from the Baltimore Multicentre AIDS Cohort Study (MACS) were studied to determine the expression of messages for the alpha and beta subunits of the IL-2R, the binding of 125I-IL-2 to high affinity IL-2R, and the effect of IL-2 on cell proliferation. Compared to HIV- donors, PHA-stimulated lymphocytes from most HIV+ donors demonstrated (i) a reduction in high affinity IL-2R expression that correlated with the reduction in the IL-2-induced proliferative response; and (ii) a reduction in expression of both IL-2R alpha- and beta-chain mRNA which may be responsible for decreased high affinity IL-2R expression. However, lymphocytes from some HIV+ individuals had borderline low IL-2-induced proliferation despite normal or elevated expression of high affinity IL-2R. These results suggest that decreased expression of IL-2R may account, at least in part, for the lower proliferative response of cells from HIV+ donors.
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PMID:Relationship between IL-2 receptor expression and proliferative responses in lymphocytes from HIV-1 seropositive homosexual men. 809 35

Members of the NF-kappa B/Rel family of transcription factors are involved in the transcriptional regulation of numerous polypeptides important to the immune response and cellular growth. Several genes regulated in part by NF-kappa B/Rel such as interleukin 2, IL-2 receptor alpha, and GM-CSF are trans-activated via an indirect association with the HTLV-I Tax protein in virus-infected and transformed T cells. In this study, we have investigated the interactions between Tax and NF-kappa B/Rel in an attempt to elucidate the mechanism of Tax mediated trans-activation and its role in leukemogenesis. Transfection studies were performed in Jurkat T cells using expression vectors for individual NF-kappa B subunits and the Tax protein as well as an NF-kappa B regulated reporter plasmid. NF-kappa B proteins differentially trans-activated the HIV-1 enhancer-CAT reporter; co-expression of Tax abrogated the inhibitory effect of I kappa B alpha and a trans-dominant negative mutant of p65 (p65 delta), indicating that Tax was a trans-dominant activator of NF-kappa B-regulated genes. Co-immunoprecipitation studies with extracts from transfected cells and NF-kappa B and Tax subunit specific antibodies revealed that Tax did not co-immunoprecipitate with p50/p105, c-Rel, or I kappa B; however, antibody specific to p65 was able to co-immunoprecipitate a 40kDa protein from Tax-transfected cells. Previous studies have demonstrated a physical interaction between Tax protein and p100, indicating that Tax may preferentially associate with specific NF-kappa B proteins.
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PMID:Interactions between HTLV-I Tax and NF-kappa B/Rel proteins in T cells. 815 9

Peripheral blood mononuclear cells from patients with the acquired immunodeficiency syndrome (AIDS), AIDS-related complex (ARC), and heterosexual controls were stimulated with anti-CD3 monoclonal antibody, phorbol myristate acetate (PMA), or both and 3H thymidine incorporation and IL-2 receptor (IL-2R alpha; CD25; Tac antigen) expression were measured. In addition, basal plasma membrane potential and plasma membrane potential following anti-CD3 stimulation were compared between the three groups. A significantly reduced DNA synthesis and CD25 expression was observed in both AIDS and ARC upon stimulation with anti-CD3 or PMA. Although, a significant synergism was observed with anti-CD3 plus PMA stimulation in both AIDS and ARC, and the responses were normalized to the levels of anti-CD3 or PMA response in normal control, the levels were significantly lower than those observed with anti-CD3 plus PMA in controls. Plasma membrane potentials were decreased (membrane depolarized) in both ARC and AIDS (AIDS > ARC), and anti-CD3 had no effect on further depolarization of plasma membrane in AIDS. These data suggest a defect in signal transduction pathway in patients with HIV-1 infection.
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PMID:Signal transduction defect in the acquired immunodeficiency syndrome and AIDS-related complex. 820 99

HTLV-I is the etiologic agent of adult T-cell leukemia. In this study, we investigated the regulatory elements and cellular transcription factors which function in modulating HTLV-I gene expression in response to the viral transactivator protein, tax. Transfection experiments into Jurkat cells of a variety of site-directed mutants in the HTLV-1 LTR indicated that each of the three motifs A, B, and C within the 21-bp repeats, the binding sites for the Ets family of proteins, and the TATA box all influenced the degree of tax-mediated activation. Tax is also able to activate gene expression of other viral and cellular promoters. Tax activation of the IL-2 receptor and the HIV-1 LTR is mediated through NF-kappa B motifs. Interestingly, sequences in the 21-bp repeat B and C motifs contain significant homology with NF-kappa B regulatory elements. We demonstrated that an NF-kappa B binding protein, PRDII-BF1, but not the rel protein, bound to the B and C motifs in the 21-bp repeat. PRDII-BF1 was also able to stimulate activation of HTLV-I gene expression by tax. The role of the Ets proteins on modulating tax activation was also studied. Ets 1 but not Ets 2 was capable of increasing the degree of tax activation of the HTLV-I LTR. These results suggest that tax activates gene expression by either direct or indirect interaction with several cellular transcription factors that bind to the HTLV-I LTR.
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PMID:Regulatory elements involved in tax-mediated transactivation of the HTLV-I LTR. 837 29

The relationship between the interleukin-2 (IL-2) system and the humoral response against human immunodeficiency virus type-I (HIV-1) is important in understanding the immune reaction before the development of AIDS. Levels of IL-2 and soluble IL-2 receptor (sIL-2R) in serum and cerebrospinal fluid (CSF) samples from 31 asymptomatic HIV-1 seropositive individuals were measured and correlated with levels of anti-1 IgG and IgM antibodies. High IL-2 levels were detected in the CSF of 20 (65%) subjects, 18 (90%) of whom had evidence of intrathecal synthesis of HIV-1-specific IgM antibodies. Similarly, IgG antibodies were detected in 10 subjects who had elevated IL-2 levels in the CSF. Moreover, intrathecal levels of IL-2 and sIL-2R correlated with intrathecal synthesis of both IgG and IgM antibodies. Local release of IL-2 seems to play an important role in the initiation of the antibody response against HIV-1 in early stages of infection and may be utilised in devising effective therapeutic strategies.
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PMID:Intrathecal synthesis of interleukin-2 and soluble IL-2 receptor in asymptomatic HIV-1 seropositive individuals. Correlation with local production of specific IgM and IgG antibodies. 846 87

The levels of soluble form of E-Selectin (sEs), or endothelial-leukocyte adhesion molecule-1, were measured in 96 sera derived from 72 HIV-infected patients at different stages of the disease, 60 healthy blood donors, and 50 HIV-negative patients with infections, using a quantitative ELISA. Levels of sEs in HIV-infected individuals without AIDS, according to the 1993 classification system of the Centers for Disease Control, were higher than normal (mean +/- SEM 48 +/- 4 versus 35 +/- 3 ng/ml, p = 0.003). Patients with established AIDS, who were afebrile and had no evidence of acute concurrent infection, had even higher sEs serum levels (70 +/- 9 ng/ml, p = 0.009, compared to those without AIDS). A significant increase in clinical category disease progression was present. Individual concentrations of sEs correlated directly with levels of soluble intercellular adhesion molecule-1 (p < 0.00001) and IL-2 receptor (p = 0.001), but not with CD4+ T-cell counts. Zidovudine treatment was not associated with changes in sEs serum levels. Elevated sEs levels were also found in HIV-seronegative patients with other bacterial and protozoal infections. Since sEs is a biologically active molecule, further studies should investigate the pathogenetic significance of circulating sEs in HIV-related disease progression, and assess the prognostic value of sEs determination for these patients.
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PMID:Levels of the circulating cell adhesion molecule E-selectin and disease progression in HIV infection. 852 77

Serum cytokine profiles, T-cell subsets, and general parameters of immune activation were evaluated in 15 patients with acute primary HIV-1 infection, and compared with those obtained from 18 patients with acute primary Epstein-Barr virus (EBV) infection and from 18 control subjects in order to elucidate possible defects of immune response to HIV in early phases of virus-host interaction. Mean CD4+ cell count, serum concentrations of interleukin (IL)-2, IL-4, soluble IL-2 receptor (sIL-2R), tumor necrosis factor (TNF)-alpha, 5'-neopterin, and beta 2-microglobulin were significantly lower in acute HIV-1 infection than in EBV infection. Both acute HIV-1 and EBV infections were characterized by significantly higher mean CD8+ cell count and soluble CD8 antigen (sCD8) levels compared to control subjects, while acute HIV-1 infection was accompanied by the highest interferon (IFN)-gamma serum concentrations. In primary HIV-1 infection, significant impairment of CD4+- mediated T-helper function may lead to viral escape and persistence of infection despite an early and vigorous CD8+ T-lymphocyte activation.
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PMID:Serum cytokine profiles in acute primary HIV-1 infection and in infectious mononucleosis. 859 86


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