Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0021051 (immunodeficiency)
71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Macrophages and microglia are the principal target cells for human immunodeficiency virus (HIV) in brain, and as such, are likely participants in the neuropathology of HIV infection. In a model system for this process, we found that fluids from human monocyte cultures enhanced survival and differentiation of the neurons in fetal rat brain explants. In contrast, fluids from HIV-infected monocyte cultures were strongly toxic to neurons and paradoxically enhanced the proliferation of glial cells. Further, neuronotoxic activity in these fluids was mediated through activation of NMDA binding receptors on the neurons and was inhibited by any of several different NMDA antagonists. Neuronotoxic activity was directly related to contamination of the HIV virus stock with Mycoplasma arginini and M. hominis. Pure cultures of mycoplasma, bacterial lipopolysaccharide (LPS), or murine recombinant tumor necrosis factor alpha (rTNF alpha) each induced neuronotoxicity which exactly mirrored that induced by the contaminated HIV stock. It is likely that mycoplasma or components of the mycoplasma plasma membrane stimulate TNF alpha production by the glial cells in the brain explants. Indeed, careful depletion of glial cells in these explants prevented mycoplasma or LPS-mediated neuronotoxicity. No neuronotoxicity was evident with HIV-1 virus stock, HIV-1 gp120, or culture fluids from HIV-infected T cells or monocytes when these preparations were free of contamination by mycoplasma and LPS. These findings suggest caution in interpretation of those experiments in which similar contamination has not been rigorously excluded.
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PMID:No direct neuronotoxicity by HIV-1 virions or culture fluids from HIV-1-infected T cells or monocytes. 159 56

This review describes the potential role of oxidative stress as a cofactor of disease progression from asymptomatic human immunodeficiency virus (HIV) infection to the acquired immunodeficiency syndrome (AIDS). Oxidative stress is a known activator of HIV replication in vitro through the activation of a factor that binds to a DNA-binding protein, NF-kappa B, which in turn stimulates HIV gene expression by acting on the promoter region of the viral long terminal repeat. Tumor necrosis factor alpha (TNF-alpha), an essential cytokine produced by activated macrophages, is also involved in the activation of HIV infection through similar mechanisms. TNF-mediated cytotoxicity of cells exposed to this substance is related to the generation of intracellular hydroxyl radicals. An indirect argument in favor of the role of oxidative stress in HIV-associated disease progression is the consumption of glutathione (GSH), a major intracellular antioxidant, during HIV infection and progression. GSH is known to play a major role in regulation of T cell immune functions. Oxidative stress may also play an important role in the genesis of cellular DNA damage and, in this context, may be related to HIV-associated malignancies and disease progression. Finally, the role of antioxidants as components of therapeutic strategies to combat HIV disease progression is discussed.
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PMID:The role of oxidative stress in disease progression in individuals infected by the human immunodeficiency virus. 164 Jan 66

NF-kappa B is a DNA-binding regulatory factor able to control transcription of a number of genes, including human immunodeficiency virus (HIV) genes. In T cells, NF-kappa B is activated upon cellular treatment by phorbol esters and the cytokine tumor necrosis factor alpha (TNF alpha). In the present work, we investigated the molecular events leading to NF-kappa B activation by TNF alpha in a human T cell line (Jurkat) and its subclone JCT6, which presents a deficiency in the PKA transduction pathway. We found that in both cell lines, both phorbol ester and TNF alpha were able to activate NF-kappa B. Phorbol activation was positively modulated by Ca2+ influx while TNF alpha activation was not. Furthermore, while PMA activation was inhibited by the PKC inhibitor staurosporin, the TNF alpha effect was unchanged. TNF alpha did not activate cAMP production and its signal was not modulated by cAMP activators. Moreover, cAMP activators did not activate NF-kappa B in Jurkat cells. Thus, TNF alpha-induced NF-kappa B activation was found to be mediated by none of the major signal-mediating kinases such as protein kinase C (PKC), protein kinase A, or Ca(2+)-regulated kinases. Furthermore, we found that cytoplasmic acidification facilitated NF-kappa B activation by both TNF alpha and PKC, by a mechanism that increases NF-kappa B/I kappa B dissociation without affecting the NF-kappa B translocation step.
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PMID:NF-kappa B activation by tumor necrosis factor alpha in the Jurkat T cell line is independent of protein kinase A, protein kinase C, and Ca(2+)-regulated kinases. 165 56

We have investigated the roles of cytokines in the modulation of human immunodeficiency virus (HIV) production in chronically infected U937 cells upon in vitro differentiation by hydroxyvitamin D3. HIV-infected U937 cells exhibited markedly lower levels of CD4 and HLA-DR antigens than uninfected cells did. Vitamin D3 induced a time-dependent macrophagelike differentiation, as determined by monitoring the expression of some surface antigens by means of the monoclonal antibodies OKM1, OKM5, OKM13, OKM14, OKT4, anti-HLA-DR, TecMG2, TecMG3, LeuM3, LeuM1, anti-HLA-DP, and anti-HLA-DQ. Treatment with hydroxyvitamin D3 resulted in a marked increase in HIV production compared with control cultures. Interleukin 1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF-alpha) were detected in the culture media, whereas interferon (IFN) was not generally found. Using the polymerase chain reaction technique, we found HIV-infected U937 cells to express detectable levels of mRNAs for alpha interferon (IFN-alpha), IFN-beta, TNF-alpha, and IL-1 beta. The addition of TNF resulted in a marked increase of HIV production, whereas IL-1 beta was ineffective. In contrast, both IFN-alpha and IFN-beta exerted some inhibitory effect on HIV production, which was more marked in vitamin D3-treated cultures than in untreated cultures. HIV production was significantly increased by antibodies to IFN-alpha in both untreated and vitamin D3-treated cultures. Anti-IFN-beta antibody increased HIV production only in vitamin D3-treated cells. In contrast, anti-TNF-alpha antibodies markedly decreased HIV production in both control and differentiating U937 cells. Vitamin D3 treatment resulted in a higher expression of TNF receptors in differentiating cells than in control HIV-infected cells. These data demonstrate a strong correlation between HIV production and macrophagelike differentiation in chronically infected U937 cells and suggest that endogenous IFN and TNF exert opposite effects in the regulation of virus production in both undifferentiated and vitamin D3-treated cell cultures.
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PMID:Increased human immunodeficiency virus (HIV) expression in chronically infected U937 cells upon in vitro differentiation by hydroxyvitamin D3: roles of interferon and tumor necrosis factor in regulation of HIV production. 170 Aug 29

Neuropathological studies have shown that human immunodeficiency virus type 1-infected cells within the brain express several markers characteristic of macrophages and could either be microglial cells, or monocytes invading the CNS, or both. To better define the target cells of human immunodeficiency virus type 1 within the brain, we have studied human microglial cells, both in vivo and in vitro, and compared them to monocytes for their antigenic markers and their susceptibility to human immunodeficiency virus type 1 infection. Brain-derived macrophages were isolated from primary cortical and spinal cord cultures obtained from 8 to 12-week-old human embryos. The isolated cells presented esterase activity, phagocyted zymosan particles, expressed several (Fc receptors, and CD68/Ki-M7 and CD11b/CR3 receptors) of the macrophagic antigenic markers, and appeared to be resident microglial cells from human embryonic brain. Conversely, brain-derived macrophages did not express antigens CD4, CD14, or CD68/Ki-M6, which are easily detected on freshly isolated monocytes. Using these antigenic differences between isolated microglial cells and monocytes, we have observed that two populations of macrophages could be individualized. In the normal adult brain, microglial cells were numerous in both the gray and the white matter. The infrequent cells sharing antigens with monocytes were found almost exclusively around vessels. In 8 to 12-week-old human embryos, microglial cells were found in both the parenchyma and the germinative layer. Cells sharing antigens with monocytes were only found at the top of and inside the germinative layer. In brain tissue from patients with human immunodeficiency virus type 1 encephalitis, cells sharing antigens with monocytes are abundant not only around the vessels but also in the parenchyma. In double-labeling experiments, human immunodeficiency virus type 1-infected cells showed monocyte antigens. Finally, microglial cells also differ from monocytes in their in vitro susceptibility to human immunodeficiency virus type 1 infection; after stimulation by r-TNF alpha or GmCSF, monocytes but not microglial cells can replicate human immunodeficiency virus type 1. This in vitro difference in human immunodeficiency virus type 1 susceptibility between monocytes and microglial cells together with the presence of monocytic antigens within the brain tissue of human immunodeficiency virus type 1-infected patients suggest that human immunodeficiency virus type 1-infected cells within the brain are either monocytes that have crossed the blood-brain barrier and spread through the tissue or perivascular microglial cells that, after phagocyting infected blood lymphocytes, subsequently contain viral antigen and migrate to brain tissue.
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PMID:Human microglial cells: characterization in cerebral tissue and in primary culture, and study of their susceptibility to HIV-1 infection. 170 49

The role of the adhesion molecules intercellular adhesion molecule-1 (ICAM-1) and LFA-1 in human immunodeficiency virus type 1 (HIV-1)-induced cell fusion was investigated in subclones of a T-cell leukemic cell line (CEM) with differing abilities to form syncytia. Addition of monoclonal antibodies 84H10 directed against ICAM-1 and MHM23 directed against the common beta subunit of LFA-1 (CD18) resulted in greater than 50% suppression of syncytia formation in cultures of these clones infected with cell-free virus. Two subclones, 2G5-144-84 and 2G5-1, were deficient in their ability to form syncytia and expressed reduced amounts of LFA-1 compared with the parental line. The expression of ICAM-1 but not LFA-1 was upregulated on the clones following treatment with interferon-gamma (IFN gamma); however, this did not overcome the delay in syncytia formation observed in these cells. The syncytia-positive subclones 1B11-39 and 17D-9 expressed high levels of LFA-1. Basal expression of ICAM-1 was upregulated on these cells by treatment with tumor necrosis factor-alpha (TNF alpha), which also accelerated and enhanced syncytia formation. However, anti-ICAM-1 and anti-LFA-1 (CD18) antibodies did not reverse the TNF alpha-induced enhancement of syncytia formation of HIV-1-infected clones 1B11-39 and 17D-9. Under conditions of low viral expression, adhesion molecules may contribute to syncytia formation if adequate levels of both receptor and ligand in the ICAM-1/LFA-1 complex are expressed.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Re-evaluation of the involvement of the adhesion molecules ICAM-1/LFA-1 in syncytia formation of HIV-1-infected subclones of a CEM T-cell leukemic line. 170 41

We studied the release of tumor necrosis factor-alpha (TNF alpha), a vital immunoregulatory cytokine, by alveolar macrophages (M phi s) infected with simian immunodeficiency virus (SIV) in vitro or collected from SIV-infected macaques. For in vitro studies, M phi s were harvested by bronchoalveolar lavage from 5 normal animals and infected in flasks with SIV (10(4)TCID50/2.5 x 10(6) M phi s). After 7 to 10 days, cytopathic effect was prominent and 68 +/- 2% of M phi s were immunoreactive for p27 core protein. Uninfected (control) and SIV-infected M phi s were then cultured for 24 hours in 96-well plates (10(5) M phi s/well) while challenged with lipopolysaccharide (LPS; 100 micrograms/ml). TNF alpha was assayed in culture supernatants by an enzyme-linked immunosorbent assay (detection limit, 50 pg/ml) and results were expressed as pg TNF alpha/ml/10(3) M phi s (mean +/- SEM). TNF alpha was not detected in unstimulated wells. TNF alpha release by control and SIV-infected M phi s was similar (6.6 +/- 0.7 and 7.9 +/- 1.1 pg/ml/10(3) M phi s, respectively). We also studied TNF alpha release by alveolar M phi s from 8 animals infected with SIV (3 asymptomatic, 5 with acquired immune deficiency syndrome virus (AIDS]. One animal with AIDS had p27+ M phi s. Alveolar M phi s from asymptomatic animals released significantly more TNF alpha (10.3 +/- 1.1 pg/ml/10(3) M phi s) than did animals with AIDS or uninfected macaques (5.2 +/- 0.8 and 7.0 +/- 0.6 pg/ml/10(3) M phi s, respectively) (p less than 0.01). However, M phi s from monkeys with AIDS failed to respond to LPS after 7 to 10 days in culture. In summary, in vitro infection with SIV does not cause constitutive TNF alpha release or alter the response of cultured M phi s to LPS. When kept in culture, M phi s collected from asymptomatic, SIV-infected animals retain their response to LPS, whereas M phi s from animals with AIDS lose the capacity to produce TNF alpha. Furthermore, M phi s cytokine production is exaggerated before overt clinical disease, but not as a direct result of infection with SIV.
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PMID:Effect of simian immunodeficiency virus infection on tumor necrosis factor-alpha production by alveolar macrophages. 189 Aug 5

Trans-activating activities of certain cellular promoter/enhancer genes may reflect the underlying mechanism for cellular differentiation. We have used two promonocytic leukemia cell lines, U937 and HL-CZ, which differ in their differentiation antigen expression. While both cell lines express CD15 antigen, only the former expresses both CD4 and CD10 antigens. These phenotypes suggest that these two cell lines appear to be arrested at different stages of differentiation. Some regions of the long terminal repeat (LTR) of human immunodeficiency virus-1 (HIV-1) contain nucleotide sequences which bind cellular trans-activating factors such as NF-kappa B and Sp1. These sequences are also present in cellular regulatory gene sequences. The cell lines have been transfected by electroporation with a nested series of deletion mutants containing different lengths of the promoter/enhancer region for HIV-LTR. The promoter/enhancer region has been linked to a 'reporter' chloramphenicol acetyl transferase (CAT) gene. We have found that promoter/enhancer trans-activation is markedly enhanced by treating transfected cells with 12-O-tetradecanoylphorbol-13-acetate (TPA), while similar treatment with tumor necrosis factor-alpha (TNF alpha) slightly enhanced activation. U937 cells always showed much greater transactivating activities than did HL-CZ cells. Deletion of a negative regulatory element (NRE) from the LTR resulted in an enhanced transactivation, while deletions affecting NF-kappa B and/or Sp1 binding sites markedly reduced transactivation. Deletion of both NRE and NRF, a second negative regulatory factor binding site, from the LTR restored the transactivation. However, in the presence of TPA, deletion of NRE sequence without concomitant deletion of the downstream NRF binding sequence was sufficient for recovering transactivation. Since these two cell lines have shown subtle differences in these responses, it may be speculated that monocytes at different stages of differentiation may respond in different ways, qualitatively and/or quantitatively, to signal transduction factors involved in the transactivation of cellular genes.
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PMID:Regulation of cellular trans-activating activities in two different promonocytic leukemia cell lines. 191 29

We have measured the production of interleukin 1 (IL 1), interleukin 6 (IL 6), and tumor necrosis factor alpha (TNF alpha) by unstimulated monocytes and monocytes stimulated with lipopolysaccharide (LPS) isolated from the peripheral blood of patients infected with human immunodeficiency virus 1 (HIV-1) and healthy controls. Spontaneous and LPS-induced cytokine production were not significantly different between patients and controls. Median lipopolysaccharide-stimulated cytokine secretion for patients and controls was 1.7 and 4.3 U/ml for IL 1, 475 and 625 U/ml for IL 6, and 468 and 580 pg/ml for TNF alpha. Cytokine levels were not related to stage of disease. We conclude that in vivo HIV infection itself does not alter peripheral blood monocyte cytokine secretion.
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PMID:Cytokine secretion by peripheral blood monocytes from human immunodeficiency virus-infected patients is normal. 193 24

"Natural" cell-mediated cytotoxicity (CMC), spontaneous release of tumor necrosis factor-alpha (TNF-alpha) by mononuclear cells in vitro and PHA-induced interferon-gamma (IFN-gamma) production were examined by standard methods (confirmed by neutralization with monoclonal antibodies) in 14 female patients with marked weight loss due to anorexia nervosa (AN) and 16 matched healthy controls. We found a significant increase in TNF production in AN, as well as a depressed CMC and IFN-gamma production. Following successful refeeding and nutritional rehabilitation of the AN patients, all results normalized to levels similar to those of controls. Thus, undernutrition in AN is accompanied by changes in cytokines and defective "natural" cytotoxicity. The implications in vivo are unclear but our findings may reflect nutritional-related immunodeficiency in AN and moreover, the increased TNF-release may further suppress food intake and enhance tissue catabolism in anorexia nervosa.
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PMID:TNF, interferon-gamma and cell-mediated cytotoxicity in anorexia nervosa; effect of refeeding. 196 35


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