Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim of this study was to determine whether polymorphonuclear neutrophils (PMN) can modify the immune response in HIV cases. Supernatants of PMN (PMNS) from 33 HIV-infected patients (16 with lymphoadenopathy syndrome, 17 with AIDS-related complex) were tested for their influence on the functional activity of lymphocytes and monocytes from 6 healthy donors. PMNS from another 6 healthy donors comprised a control group. It was found that PMNS from HIV-infected patients, but not from healthy donors, induced suppression of lymphocyte proliferative response and down-regulation of CD8 receptor expression on lymphocytes. Decrease of NK-cell cytotoxicity in the presence of PMNS from HIV-infected patients was the same as that from healthy donors. PMNS did not influence the production of anti-HIV antibody by lymphocytes from HIV-infected patients, as well as non-specific IgG by lymphocytes from healthy donors. PMNS effect on functional activity of lymphocytes was blocked completely after treatment of PMN by catalase and superoxide dismutase. At the same time PMNS from HIV-infected patients but not from healthy donors induced increased production of TNF-alpha by monocytes and up-regulation of monocyte phagocytosis. These effects were independent of catalase and superoxide dismutase and were not abrogated by antibody against IL-1, IL-8, TNF-alpha, IFN-gamma or IFN-alpha.
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PMID:Modification of lymphocyte and monocyte functional activity by polymorphonuclear neutrophils in HIV infection. 846 29

HIV-1 infection is associated with a progressive and functional decline in the CD4+ lymphoid Th1 subset. Here, we propose that the HIV nef gene product may function as a specific regulator of Th1 cytokine production. By use of a T cell-specific inducible expression system, we show that upon T cell activation, induced nef expression down-regulated both IL-2 and IFN-gamma production in a dose-dependent manner, whereas IL-4, IL-9, IL-13, IL-8, and TNF-alpha production remained unaffected. In addition to this, independent transfected clones expressing various nef genes, including nef sequences amplified directly from an HIV-1 primary clinical isolate, displayed a similar pattern of cytokine expression. The specific Th1 impairment induced by nef, therefore, seems to be an important and conserved feature of HIV-1 infection and may represent a significant function of this viral gene in AIDS pathogenesis.
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PMID:Specific Th1 cytokine down-regulation associated with primary clinically derived human immunodeficiency virus type 1 Nef gene-induced expression. 859 86

The host response to Mycobacterium tuberculosis is dependent on the accumulation and activation of cytotoxic and memory CD4+ T cells, resulting in granuloma formation and delayed type hypersensitivity. We characterized the cellular response of radiographically involved lung segments from 17 HIV-positive and 11 HIV-negative patients with acute tuberculosis (TB) using bronchoalveolar lavage (BAL) and compared the response to uninvolved segments, normal control subjects and peripheral blood. In both HIV-positive and HIV-negative patients, radiographically involved segments had significantly increased numbers of total cells per milliliter, percent of neutrophils recovered, and percent of lymphocytes recovered compared with uninvolved segments or normal control subjects, but HIV-positive patients had a lower proportion of lymphocytes in the involved segments than HIV-negative patients with tuberculosis (19 +/- 5% versus 33 +/- 5%; p < 0.05). Lymphocyte subset analysis demonstrated that HIV-positive patients had markedly reduced percentages of CD4+ lymphocytes (CD4+ lymphocytes in HIV-positive TB involved site 25 +/- 6%; HIV-negative TB involved site 73 +/- 2%; p < 0.01) and an increase in the percentage of CD8+ lymphocytes (HIV positive involved site 61 +/- 6% versus HIV negative involved site 19 +/- 3%; p < 0.01). Immunohistochemistry of lung biopsy tissue in five HIV-negative patients showed similar lymphocyte subset profiles as BAL, indicating that BAL reflects cell populations in tissue granulomas. BAL lymphocytes from four HIV-positive and four HIV-negative tuberculosis patients demonstrated immune activation by staining with a murine antibody to TIA-1, a cytoplasmic protein associated with cytotoxicity and apoptosis (HIV positive 48 +/- 6%, HIV negative 31 +/- 7%, normals 11 +/- 5%). Steady state mRNA for gamma-interferon was decreased in four HIV-positive patients when compared with four HIV-negative patients. IL-8 production was comparable in HIV-negative and HIV-positive patients with focal disease but reduced in two patients with miliary tuberculosis. We conclude that HIV-positive patients with+ tuberculosis have a reduced enrichment and activation of immune cells in the lung, and this failure of a CD4+ alveolitis limits an effective immune response.
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PMID:Tuberculosis in HIV-positive patients: cellular response and immune activation in the lung. 861 69

A proportion of HIV-infected individuals experience episodes of localized or systemic bacterial infections caused by Gram-negative bacteria. Many of the clinical side effects of these infections are associated with the production of proinflammatory cytokines, which are induced primarily by LPS, a constituent of the bacterial cell wall of Gram-negative bacteria. The present study examines the mechanisms involved in LPS-mediated induction of HIV expression in U1 cells, a promonocytic cell line chronically infected with HIV. Stimulation of U1 cells by LPS alone induced minimal levels of HIV expression, which was significantly enhanced by granulocyte-macrophage colony-stimulating factor (GM-CSF). Costimulation of U1 cells with LPS plus GM-CSF resulted in the accumulation of steady-state levels of HIV RNA; however, only a weak induction of HIV long terminal repeat-driven transcription, which was not associated with the activation of the cellular transcription factor nuclear factor-kappa B, was noted. Costimulation of cells with LPS plus GM-CSF induced the production of proinflammatory cytokines, IL-8, IL-1 beta and IL-6, but not TNF-alpha. IL-1 receptor antagonist (ra) inhibited LPS enhancement of HIV expression in GM-CSF-stimulated cells, suggesting that endogenous IL-1 was involved in LPS-mediated viral production. In this regard, anti-inflammatory cytokines inhibited LPS plus GM-CSF-stimulated HIV expression, and this effect closely correlated with inhibition of IL-1 beta release and, in particular, with up-regulation of endogenous IL-1ra production. Thus, the balance between an endogenously produced viral inducer (IL-1 beta ) and an inhibitor (IL-1ra) may represent an important pathway leading to modulation of HIV expression from monocytic cells.
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PMID:Modulation of endogenous IL-1 beta and IL-1 receptor antagonist results in opposing effects on HIV expression in chronically infected monocytic cells. 861 79

Vascular endothelial cells (EC) play a key role in viral tropism in vivo. Since conflicting reports have been published on the capability of HIV to infect EC in vitro, we analyzed some factors potentially capable of influencing the susceptibility of human umbilical vein endothelial cells (HUVEC) to HIV-1. Both primary cultures and differentiated immortalized HUVEC lines were used. HUVEC were negative for the expression of CD4, but weakly CD26- and galactosylceramide-positive. Although binding of HIV to EC was substantial, the virus was apparently incapable of replicating in nonproliferating cultures. In resting cultures, the content of cell-associated HIV disappeared 4-6 days after infection without production of p24 and infectious progency. In contrast, infection of proliferating EC cultures led to the transient release of p24 and infectious virus (10(2.5)-10(3.5) SFU/ml) peaking 2-6 days postinfection. Antibody neutralization of cytokines that may be produced by EC (IL1, IL6, IL8, TNF, IFN-beta) failed to modify virus adsorption and replication, whereas treatment with IL1-beta plus TNF-alpha stimulated both virus binding and virus release. As seen by gag polymerase chain reaction (PCR), the viral genome persisted up to 15 days in untreated EC cultures, but over 20 days in cultures exposed to IL1-beta plus TNF-alpha. This study shows that: (a) CD4-negative HUVEC are capable of binding substantial amounts of HIV-1; (b) binding is enhanced by proinflammatory cytokines; (c) the establishment of productive infection is favored by cell proliferation; and (d) exposure to IL1-beta plus TNF-alpha enhances virus replication.
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PMID:Productive HIV-1 infection of human vascular endothelial cells requires cell proliferation and is stimulated by combined treatment with interleukin-1 beta plus tumor necrosis factor-alpha. 863 3

Human polymorphonuclear neutrophils (PMN) and cytokines play a critical role in host defences against invading microorganisms. In response to a variety of stimuli, PMN are a major source of reactive oxygen species (ROS) which are essential for bacterial killing and may induce oxidative stress in tissue environment. A precise regulation of the oxidase activity is therefore necessary. Cytokines such as TNF alpha, GM-CSF, IL-8, IL-6, IL-1 alpha and IL-1 beta produced during the immune and inflammatory responses to pathogens have been reported to interact with PMN activities. However, contradictory results have been reported on their direct and priming effects on the PMN release of ROS (oxidative burst). We have used a flow cytometry method to study the effects of these cytokines on the oxidative burst of PMN in whole blood, in order to avoid PMN activation related to isolation procedures. None of the cytokines tested directly activated the PMN oxidative burst, but they did have differential priming effects on the oxidative burst in response to N-formyl peptides. TNF, GM-CSF and IL-8 strongly primed a subpopulation of PMN to produce H2O2 in response to fMLP, while IL-1 alpha, IL-1 beta and IL-6 failed to do so. Furthermore, the addition of TNF, GM-CSF or IL-8 to whole blood increased the capacity of a subpopulation of PMN to bind N-formyl peptides, a phenomenon that could account for the strong H2O2 production in response to fMLP following priming by the cytokines. These results show that, among the various cytokines tested, TNF, GM-CSF and IL-8 strongly prime the PMN oxidative burst in response to bacterial peptides in whole blood and suggest that these cytokines may play a critical role in bacterial killing in vivo and also in the surrounding tissue injury secondary to pathological inflammatory reactions. In particular, TNF and IL-8 plasma levels as well as LPS-induced monocytic production of these cytokines ex vivo have been correlated with the production of ROS by stimulated PMN and with the lung injury score in patients with Adult Respiratory Distress Syndrom (ARDS). However, desensitization phenomena have also been described. In particular, in HIV infected patients we demonstrated a decrease of H2O2 production by PMN in whole blood after ex vivo priming by IL-8 and TNF followed by fMLP stimulation. This decrease increased with the progression of the disease and was inversely correlated with IL-8 plasma level. Different mechanisms could explain such desensitization phenomena at the receptor and post receptor level. In addition cytokines are involved in a complex network of regulation and anti inflammatory cytokines, such as IL-10, could act as a negative signal on the proinflammatory cytokines induced-priming of oxidative burst.
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PMID:[Modulation of the oxidative burst of human neutrophils by pro- and anti-inflammatory cytokines]. 873 98

The human immune response to tuberculosis is partly mediated by the proinflammatory cytokines tumour necrosis factor (TNF), interleukin (IL)-6, and IL-8. We investigated plasma concentrations of these cytokines before and after maximal lipopolysaccharide stimulation ex vivo of whole blood leucocytes from Zambian patients. 32 patients with non-fatal tuberculosis, 25 of whom were seropositive for human immunodeficiency virus (HIV), were followed for 9 months. Patients were assessed at presentation to hospital (visit A), after 2 months' antimycobacterial therapy (visit B), and when chemotherapy was completed (visit C). Between visits A and B, patients regained weight (P = 0.03) and became less anaemic (P = 0.0001). At visit B, haemoglobin concentration remained lower in HIV seropositive patients (P = 0.001) and the erythrocyte sedimentation rate (ESR), initially elevated in all patients, was higher in HIV seropositive patients (100 +/- 6 mm vs. 43 +/- 11 mm in 1 h in seronegative patients; P = 0.002). Plasma IL-8 concentrations were increased at visit C as was IL-8 secretion ex vivo (P < 0.0001 at all time points). Otherwise plasma cytokine levels and secretion ex vivo remained similar throughout the study. Concurrent HIV infection resulted in persistently decreased IL-6 secretions ex vivo although ESR remained high. In summary, after antibiotic therapy in vivo IL-8 secretion ex vivo increased, which supports other data suggesting that IL-8 has a role in immunity to tuberculosis.
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PMID:Cytokine secretion in vivo and ex vivo following chemotherapy of Mycobacterium tuberculosis infection. 876 91

The major characteristic lesion observed following spontaneous infection of sheep by the prototype lentivirus, maedi-visna virus (MVV), is a lymphocytic intestitial pneumonia. Similar lesions may be observed with variable frequency following infection of other species by pathogenic lentiviruses, for example in children infected by HIV-1. Further, lentivirus-induced lesions involving organs other than the lungs frequently involve a comparable cellular infiltration. The cellular composition of bronchoalveolar lavage specimens from naturally- or experimentally-infected sheep has been examined with a view to describing the pathological progression of lentivirus-induced lung lesions. The naturally-infected sheep presented advanced lesions typical of 'maedi', while the experimentally-infected newborn lambs permitted the study of early lesions which we refer to as 'pre-maedi'. In both cases there was a considerable infiltration of lymphocytes, predominantly CD8+ in maedi, but with nearly equal numbers of CD4+ cells in pre-maedi. A large proportion of the alveolar lymphocytes in spontaneous maedi, but not in experimentally-infected lambs, express high levels of MHC class II antigen, suggesting an activated phenotype. Activated macrophages, the chief target cells for MVV infection, are also present at this advanced stage of the disease suggesting the involvement of mediators such as IL-8 in the cellular interactions leading to the localization of particular lymphocyte sub-populations in the pulmonary parenchyma during lentiviral disease.
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PMID:Histogenesis of the pulmonary lesions in the course of visna maedi virus-induced pneumonia. 882 12

We determined the degree of activation of the TNF alpha system and the levels of IL-8 in HIV-1 infection. TNF alpha is one of the most potent agents for the induction of IL-8. TNF alpha may be cleared rapidly from the circulation, however soluble tumor necrosis factor receptor (sTNFR) p75 which is more stable may reflect the degree of activation of the TNF alpha system. We measured concentrations of sTNFR p75 and IL-8 with immunoassays in the plasma of 99 HIV-1-infected patients at different stages of disease (Centers for Disease Control classification) and in 20 healthy control subjects. Plasma levels of sTNFR p75 were elevated in most of the asymptomatic seropositive patients without CD4+ T cell depletion (Stage IIA) and in most of patients of all clinical groups compared with controls. However, in the majority of those patients plasma levels of IL-8 were not higher than those of controls. Our results suggest that sTNFR p75 levels but not IL-8 levels in circulating blood are high in the course of HIV-1 infection.
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PMID:Plasma levels of sTNFR p75 and IL-8 in patients with HIV-1 infection. 887 20

Cells of the macrophage lineage (MAC) play an important role in human immunodeficiency virus (HIV) infection. However, the knowledge on the extent of macrophage involvement in the pathogenesis of HIV infection is still incomplete. In this study we examined the secretory repertoire of HIV-infected MAC with respect to the proinflammatory cytokines tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), IL-6, IL-8, and the hematopoietic growth factors M-, G- and granulocyte-macrophage colony stimulating factor (GM-CSF). Using a culture system on hydrophobic teflon membranes, blood-derived MO from healthy donors were infected with a monocytotropic HIV-1 isolate (HIV-1D117IIII). We analyzed the constitutive and lipopolysaccharides-stimulated secretion of MO/MAC early after infection as well as in long-term cultured, virus-replicating cells. The release of proinflammatory mediators and hematopoietic growth factors were differentially regulated after infection with HIV: the secretion of TNF-alpha, IL-1 beta, IL-6, IL-8 was upregulated, whereas a down-regulation of M-, G-, and GM-CSF could be observed. These results may provide some explanation for the immunological dysfunction, the hematopoietic failure and the chronic inflammatory disease occurring in HIV-infected patients.
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PMID:Differential regulation of proinflammatory and hematopoietic cytokines in human macrophages after infection with human immunodeficiency virus. 889 13


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