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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

TNF-alpha enhances HIV-1 replication in acutely and chronically infected cells and likely contributes to the wasting associated with the acquired immunodeficiency syndrome. Agents that inhibit TNF-alpha activity should theoretically delay the progression of disease, and several are currently in clinical trials. We hypothesized that IL-10, a cytokine that suppresses the gene expression and synthesis of TNF-alpha in monocytic cells, might inhibit HIV-1 replication. As expected, IL-10 suppressed PMA-induced TNF-alpha production in U1 cells; however, when U1 cells were cultured in the presence of PMA and increasing doses of IL-10, a dose-dependent increase in HIV-1 expression was observed. IL-10 also enhanced IL-1 beta-, TNF-alpha-, and GM-CSF-induced HIV-1 expression in U1 cells, and this occurred, at least in part, at the level of transcription. We next stimulated cells under conditions of TNF-alpha blockade. When PMA-induced TNF-alpha activity and HIV-1 replication were blocked by the presence of soluble TNF receptors, IL-10 independently enhanced HIV-1 replication. In contrast, other agents that are capable of blocking TNF-alpha synthesis or TNF-alpha activity either had no effect (IL-13 and IL-4) or inhibited HIV-1 expression (soluble TNF receptors and pentoxifylline) in U1 cells. These data suggest that IL-10, while inhibiting TNF-alpha synthesis, has an independent mechanism of action that enhances HIV-1 replication. Therefore, IL-10 may have undesirable effects in HIV-1-infected patients.
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PMID:Interleukin-10 enhances human immunodeficiency virus type 1 expression in a chronically infected promonocytic cell line (U1) by a tumor necrosis factor alpha-independent mechanism. 755 27

Elevated levels of circulating monokines (IL-6, IL-1, and TNF alpha) have been seen in HIV-1 infection, and the overproduction of these cytokines could contribute to AIDS pathogenesis in various ways. In previous work, we had seen that exposure of human monocytes to HIV-1, including inactivated, noninfectious HIV, led to rapid IL-6 gene expression and secretion. To investigate cytokine production in response to components of HIV by monocytes/macrophages, production of IL-6 and IL-10 were examined in a human monocytic cell line, THP-1, stimulated by HIV proteins. IL-6 production was induced in THP-1 cells by a detergent lysate of HIV, particularly fractions at molecular weight of 25-50 kDa. Recombinant HIV envelope glycoprotein 41 (gp41), but not gp120 or p24, also was seen to induce significant IL-6 production by THP-1 cells. These results suggest that gp41, transmembrane protein, is the primary HIV-encoded protein involved in inducing IL-6 production. IL-10 was also produced with delayed kinetics, following IL-6 production in THP-1 cells stimulated by gp41. To investigate a possible regulatory role for IL-10 in HIV-induced monokine production, recombinant IL-10 was added to gp41-exposed THP-1 cells. IL-10 inhibited gp41-induced IL-6 production and reduced the expression of IL-6 mRNA. When anti-human IL-10 neutralizing antibody was added to THP-1 cells, IL-6 production was enhanced. These results suggest that the IL-6 production may be downregulated by endogenously produced IL-10 and that IL-10 may downregulate cytokine production by HIV-activated monocytes via an autoregulatory mechanism.
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PMID:Induction of IL-6 and IL-10 production by recombinant HIV-1 envelope glycoprotein 41 (gp41) in the THP-1 human monocytic cell line. 755 88

Bacterial lipopolysaccharide (LPS) modulates expression of a variety of genes in macrophages, and additionally activates viral promoters including the HIV-1 LTR. The HIV-1 LTR driving the luciferase reporter gene was stably transfected into the murine macrophage cell line, RAW264. In stably transfected cells, luciferase activity was LPS-dependent. As little as 0.01 ng/ml LPS was sufficient to increase luciferase activity over basal levels with maximal stimulation resulting in a 10- to 20-fold response. The cells also responded to human and murine tumour necrosis factor (TNF alpha). Endogenous TNF alpha was not involved in LPS responses, since pretreatment with alpha-TNF alpha antibody did not affect activation. Induction of HIV-1 LTR activity by LPS occurred independently of phorbol myristate acetate (PMA) sensitive protein kinase C (PKC), since depletion of PKC by prolonged exposure to PMA blocked TNF alpha and PMA responses but was not able to abolish LPS action on these cells. Taxol (5-20 micrograms/ml), a chemotherapeutic agent which mimics LPS action on macrophages, was also able to increase expression of the reporter gene driven by the HIV-1 LTR. However, lower doses of taxol that were not sufficient to trans-activate the LTR or to induce TNF alpha expression were cytotoxic to RAW264 cells suggesting that the cytotoxic and LPS-like activities of taxol were not linked. This cell line provides a convenient method for detecting LPS-like activity and is a useful tool for examining LPS and TNF alpha signalling pathways.
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PMID:RAW264 macrophages stably transfected with an HIV-1 LTR reporter gene provide a sensitive bioassay for analysis of signalling pathways in macrophages stimulated with lipopolysaccharide, TNF-alpha or taxol. 758 58

In this study we have raised spontaneous Epstein-Barr virus (EBV)-positive lymphoblastoid cell lines (LCL) from the peripheral blood of human immunodeficiency virus (HIV)-infected individuals and of control patients with primary EBV infections. These LCLs were also raised in the presence of the viral inhibitor phosphonoformate (PFA); under these conditions, the in vitro infection of bystander B lymphocytes with EBV released in culture by in vivo infected B cells is inhibited. Thus, the latter LCLs are likely to represent the progeny of B cells latently infected by EBV in vivo. The LCLs raised in the presence or absence of PFA had the same phenotypic features, type of EBV latency, and growth pattern irrespective of whether they had been raised from HIV-seropositive individuals or patients with primary EBV infections or had been generated by infecting normal B cells in vitro. Studies on the production of inflammatory cytokines were conducted by Northern blotting or by determining the cytokine concentrations in the cell supernatants by immunoassays or bioassays. Three of eight LCLs from HIV-seropositive patients released TNF alpha and 5/5 released TNF beta, IL6 was present in the supernatants of 1/8 LCLs, and IL1 alpha and IL1 beta were not detected in any culture supernatant. No differences were noticed in the patterns of cytokine secretion among the LCLs from HIV-seropositive patients and in those raised from patients with primary EBV infections or obtained by infecting normal B cells in vitro with EBV. It is tempting to speculate that abnormally expanded EBV-harboring B cells in HIV-seropositive patients may participate in the pathogenesis of certain clinical manifestations by releasing inflammatory cytokines; some of these cytokines might also contribute to the in vivo spreading of HIV infection. However, the spontaneous LCLs from HIV-seropositive individuals do not display abnormal features compared to latently EBV-infected LCLs from other sources despite the high frequency of EBV-driven lymphoproliferative disorders observed in AIDS patients.
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PMID:Production of inflammatory cytokines by Epstein-Barr virus (EBV)-infected lymphoblastoid cell lines spontaneously originated from the peripheral blood of patients with human immunodeficiency virus (HIV) infection. 758 23

Ultraviolet B (UVB) radiation in sunlight damages the cutaneous immune system of individuals primarily by converting trans-urocanic acid (UCA) to its cis isoform which in turn instigates excessive local, and eventually systemic, levels of tumor necrosis factor-alpha (TNF alpha). UVB radiation and TNF alpha have been found to activate HIV from the latent state, and TNF alpha has been implicated in the pathogenesis of several manifestations of the acquired immune deficiency syndrome (AIDS). We hypothesize that the immunosuppressant properties of TNF alpha and cis-UCA, released by intense sun exposure, can accelerate the onset and progression of AIDS in HIV-infected individuals.
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PMID:Sunlight induced progression of AIDS. 759 5

The effects of cysteamine (2-aminoethanethiol, MEA) and its disulfide, cystamine, on the human immunodeficiency virus (HIV-1) expression in chronically infected promonocytic cells (U1), T cell line (ACH-2), and peripheral blood monocyte-derived macrophages (MDM) were investigated. U1 and ACH-2 cells constitutively express low levels of virus, which is increased by the addition of tumor necrosis factor (TNF-alpha), interleukin 6 (IL-6), granulocyte-macrophage-colony-stimulating factor (GM-CSF), and other inducers. Cystamine, in noncytotoxic doses, suppressed in a concentration-dependent fashion the induction of HIV-1 expression mediated by TNF-alpha, IL-6, GM-CSF, and monokine-enriched monocyte culture supernatants in both U1 and ACH-2 cells as determined by HIV-1 reverse transcriptase (RT) activity. Similarly, HIV-1 expression was substantially reduced in the cystamine-treated primary MDM cultures compared with the untreated control cultures. The addition of cystamine into HIV-1 chronically infected MDM (12 days after infection was established) also suppressed 80-90% of RT activity in comparison to the untreated controls. HIV-1 (Bal) infected MDM cultures (without cystamine treatment) demonstrated giant syncytium formation, whereas cystamine-treated cultures lacked the giant syncytia induced by HIV-1 infection. Cystamine also inhibited LPS-induced TNF production in MDM. In contrast to cystamine, cysteamine showed no significant effects on either the monokine-induced HIV-1 expression in U1 or ACH-2 or acute and chronic HIV-1 infection in MDM.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cystamine inhibits HIV type 1 replication in cells of monocyte/macrophage and T cell lineages. 763 61

Interaction of HIV with cultured human monocytes triggers not only cytokine production but also the release of natural cytokine inhibitors such as the soluble TNF receptors, levels of which are increased in the circulation of HIV-infected patients. We found that HIV-1 LAI induced the production by human monocytes from HIV-seronegative donors of another type cytokine inhibitor, the IL-1Ra receptor antagonist (IL-1Ra). HIV mainly induced the secreted form (83%) of IL-1Ra through de novo mRNA synthesis. IL-1Ra production was triggered at an early step of the infection process and involved the HIV envelope protein and the CD4 receptor. HIV-triggered IL-1Ra production occurred after a lag time, suggesting an indirect mechanism. Neutralizing Abs to IL-1 beta and IL-10 had no effect, while simultaneous treatment with anti-TNF-alpha, anti-granulocyte-macrophage CSF, and anti-TGF-beta nearly abrogated IL-1Ra release, supporting an indirect induction through the concerted action of the co-produced cytokines. IL-1Ra was induced by HIV in a mean 1,000-fold increase over IL-1 alpha beta, a ratio 20-fold higher than that obtained with LPS. This production masked 80% of IL-1 bioactivity in HIV-induced monocyte supernatants. These results suggest that the net balance between pro-inflammatory cytokines and their natural inhibitors could be critical in the control of the inflammatory process associated with HIV infection.
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PMID:HIV predominantly induces IL-1 receptor antagonist over IL-1 synthesis in human primary monocytes. 765 Apr 4

The aetiology of the bone marrow suppression in HIV-infected patients is unknown. We have demonstrated previously that the ability of bone marrow cells, derived from mice made immunodeficient by infection with the retrovirus LP-BM5, to establish long-term stromal cultures is impaired. In this study we determined the ability of bone marrow stromal cells from these immunodeficient mice to produce cytokines important in haemopoiesis. Neither SCF, IL-3, GM-CSF nor TNF alpha were found in conditioned media of long-term bone marrow cultures (LTBMC) of normal or MAIDS mice. We failed to detect mRNA for TNF or IL-1 alpha, by reverse transcription polymerase chain reaction (RT-PCR), in cultures derived from either normal or immunodeficient mice. Steady-state levels of transcripts for IL-6 were equal in cells from normal and MAIDS mice. Steady-state levels of mRNA for TGF beta 1, a known inhibitor of haemopoiesis, were decreased in cultures derived from MAIDS mice at late stages of infection. The mRNA level of the multipotent haemopoietic regulator stem cell factor was also decreased in MAIDS cultures as compared with normals. Transcripts encoding the transmembrane form of the growth factor were almost absent. Addition of soluble GM-CSF and SCF only transiently increased the production of CFUs (BFUE and CFU-G/M) in MAIDS LTBMC. These findings suggest that derangements in cytokine production in stromal cells of immunodeficient mice may contribute to the suppression of haemopoiesis observed in this disease. One mechanism of HIV-induced depression of haemopoiesis may be via alterations of the haemopoietic microenvironment.
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PMID:Impaired cytokine production by bone marrow stromal cells of immunodeficient mice. 766 53

The inflammatory cytokine tumor necrosis factor alpha (TNF-alpha) has been shown to stimulate human immunodeficiency virus type 1 (HIV-1) replication in both chronically and acutely infected T lymphocytes and monocytes. Transcriptional activation of the HIV long terminal repeat and subsequent increase in virus production are linked to TNF activation of the cellular transcription factor NF-kappa B. Here we report the use of two forms of soluble recombinant type 1 (p80) TNF receptor to inhibit TNF-induced HIV activation in vitro. One receptor form is a monomer containing the entire 236 residues of the extracellular (ligand-binding) portion of p80. A second receptor form is a chimeric homodimer containing these residues fused to a truncated human IgG1 immunoglobulin heavy chain and, thus, resembles a bivalent antibody without light chains. These recombinant receptor proteins were tested for their ability to inhibit TNF-alpha-induced expression of HIV-1 in chronically infected human cell lines. We also examined the ability of the soluble receptors to limit the activation of the HIV-long terminal repeat transcription. The soluble TNF receptor dimer was most effective at blocking TNF-alpha-induced HIV-1 expression in both monocytoid and lymphoid cells. The molar ratio of TNF-receptor dimer to TNF-alpha found to be most effective was, at least, 5:1. We conclude that at specific TNF/soluble TNF-receptor dimer ratios, TNF-alpha-induced HIV-1 transcription and expression can be limited in vitro.
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PMID:Soluble tumor necrosis factor receptor: inhibition of human immunodeficiency virus activation. 768 92

The present experiments were designed to study whether GTP binding protein activation and the resulting cAMP plays any role in HIV replication. The results showed that cholera toxin (CT) enhanced HIV replication dose dependently in myelo-monocytic cell lines latently infected with HIV-1, U1 and J22HL-60. Three- to 4-fold enhancement of virus production was observed in U1 cells and 4- to 11-fold enhancement in J22HL-60 cells 4 days after treatment with 100 ng/ml of CT. The increment of intracellular cAMP accumulation was parallel with HIV augmentation by CT in both cells. Even at the low concentration 0.1 ng/ml, TNF enhanced virus production to about an 80-fold higher level than the untreated U1 control cells as described previously (11). However, a synergistic effect (80- to 238-fold enhancement) was observed, when TNF-alpha and CT were added together to U1 cells. Similar synergism was seen in J22HL-60 cells. HIV antigen positive cells and gp120 expression were also increased to a similar degree. Phosphodiesterase inhibitor IBMX had no effect on HIV production alone, but potentiated HIV induction by CT and TNF. Adenylate cyclase activator, forskolin (FK), at 100 microM also significantly augmented HIV production (> 4-fold) and potentiated TNF induction in J22HL-60 and U1 cells. On the other hand, CT did not show any effect on HIV replication as well as TNF induction in HIV-1-infected T cell line. Northern blot experiment confirmed that this enhancement was mediated through the activation of HIV transcription. These data suggest that cAMP augments HIV replication and potentiates TNF induction in a particular monocyte-macrophage system.
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PMID:cAMP stimulates human immunodeficiency virus (HIV-1) from latently infected cells of monocyte-macrophage lineage: synergism with TNF-alpha. 768 59


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