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Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human immunodeficiency virus (HIV-1) infection in the human brain leads to characteristic neuropathological changes, which may result indirectly from interactions of the envelope glycoprotein gp120 with neurons and/or glial cells. We therefore investigated the binding of recombinant gp120 (rgp120) to human neural cells and its effect on intracellular signalling. Here we present evidence that rgp120, besides binding to galactocerebroside or galactosyl-sulfatide, specifically binds to a protein receptor of a relative molecular mass of approximately 180,000 Da (180 kDa) present on the CD4-negative glioma cells D-54, but not on Molt4 T lymphocytes. Binding of rgp120 to this receptor rapidly induced a tyrosine-specific protein kinase activity leading to tyrosine phosphorylation of 130- and 115-kDa proteins. The concentration of intracellular calcium was not affected by rgp120 in these cells. Our data suggest a novel signal transducing HIV-1 gp120 receptor on CD4-negative glial cells, which may contribute to the neuropathological changes observed in HIV-1-infected brains.
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PMID:HIV-1 gp120 receptor on CD4-negative brain cells activates a tyrosine kinase. 136 Jan 81

Astrocytes have been regarded as the matrix of the central nervous system and as nutritional, metabolic support to neurons. Recently, immunological roles of astrocytes have been reported, especially in multiple sclerosis and experimental allergic encephalitis. One observation shows that human glioma cells, which lack CD4 molecules, can be infected with human immunodeficiency virus in vitro. Another report described that human macrophages can be infected with human immunodeficiency virus through Fc gamma receptors expressed on their cell surfaces. These results prompted us to examine the functioning molecules, especially Fc gamma receptor for immunoglobulin G, expressed on the astroglial cell line. From erythrocyte-antibody rosette assays, redirected cytolysis and flow cytometric analysis, we have shown that human astrocytoma cell lines possess Fc gamma receptors on their cell surfaces. Furthermore, primary cultured murine astrocytes express Fc gamma II receptors, reacting with 2.4G2 monoclonal antibody. Surprisingly, murine astrocytes prepared from newborn BALB/c mice demonstrate killing activity against allogeneic T cell leukemia by antibody-dependent cellular cytotoxicity. After treatment with the macrophage activating factor, interferon-gamma, expression of Fc gamma receptors and killer activity of astrocytes were augmented. From these results, it is suspected that the astroglial cell lines play an important immunological role in the brain.
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PMID:Expression of Fc gamma receptors on astroglial cell lines and their role in the central nervous system. 138 16

Human CD4 was expressed on a range of mammalian cell lines. CD4+ non-primate cells, derived from rat, hamster, mink, cat, and rabbit, bind recombinant gp120 of human immunodeficiency virus type 1 (HIV-1) but are resistant to HIV-1 infection. CD4 expression on various human, rhesus, and African green monkey cell lines confers differential susceptibilities for HIV-1, HIV-2, and simian immunodeficiency (SIV) strains. For example, CD4+ TE671 rhabdomyosarcoma cells are sensitive to HIV-1 and HIV-2 but resistant to SIV, whereas CD4+ U87 glioma cells are resistant to HIV-1 infection but sensitive to HIV-2 and SIV. HIV-1 infection was not dependent on human major histocompatibility class I expression. Studies of cell fusion and of infection by vesicular stomatitis virus pseudotypes bearing HIV-1 and HIV-2 envelopes showed that the differential cell tropisms of HIV-1, HIV-2, and SIV are determined at the cell surface.
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PMID:Specific cell surface requirements for the infection of CD4-positive cells by human immunodeficiency virus types 1 and 2 and by Simian immunodeficiency virus. 167 40

Astrocytes are regarded as matrix of the neuron in central nervous system (CNS) and involve nutritional and supporting function of neuron. It was clarified that human and murine cultured astrocytes had Fc receptor (FcR) on their cell surface from the study of EA rosette assay, reverse ADCC (antibody dependent cellular cytotoxicity) and flow cytometric analysis with anti-FcR monoclonal antibodies (mAb) in this study. Human glioma cells express FcR III recognized by mAb MG 12 and mouse astrocytes express FcR II recognized by mAb 2.4 G 2. Expression of FcR on human astrocytes is compatible with FcR-mediated human immunodeficiency virus (HIV)-1 infection in CNS. Expression of adhesion molecules engaged in T and natural killer cell cytotoxicity was also investigated for human glioma cells. CD 56 (NKH-1 or Leu 19), which is an isoform of N-CAM (neural cell adhesion molecule) mainly distributed on human NK cells and a subset of T cells, was also expressed in neuroglial cells. LFA-3, a ligand for CD 2, but not ICAM-1, a ligand for LFA-1, was, expressed on glioma cells. So, CD 56 was suggested to be a new adhesion molecule in NK cell mediated lysis of glioma cells by their homotypic adhesive character.
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PMID:[Analysis of receptor expression on astrocytic cells]. 170 27

Human promonocyte cells chronically infected with human immunodeficiency virus type (HIV-1) (clone U1.1.5) were grown in the presence of media conditioned by human astrocytes and glioma cell lines U251 and 253. HIV-1 expression was assessed by measuring reverse transcriptase activity. All media conditioned by unstimulated and lipopolysaccharide (LPS) stimulated glial cells induced HIV-1 expression and contained detectable levels of interleukin-6 (IL-6) but not tumor necrosis factor-alpha (TNF-alpha). An antibody against IL-6, but not against TNF-alpha, reduced the induction of HIV-1 by the conditioned media in a concentration-dependent manner. The magnitude of HIV-1 induction by the conditioned media was proportional to the concentration of IL-6 in them. The data indicate that normal and transformed human astrocytes are capable of stimulating HIV-1 expression in chronically infected promonocytic cells by secreting IL-6. The results demonstrate that cytokines secreted by neural cells could play an important role in regulating HIV-1 expression in the brain.
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PMID:Human astrocytes stimulate HIV-1 expression in a chronically infected promonocyte clone via interleukin-6. 174 78

The human immunodeficiency virus (HIV) genome codes for a trans-activating regulatory protein, tat. Using chemically synthesized tat, it was found that 125I-tat and 125I-tat38-86 specifically bound to rat brain synaptosomal membranes with moderate affinity (K0.5 = 3 microM). Interaction of tat with nerve cells was also revealed by flow cytometry, which showed its binding to rat glioma and murine neuroblastoma cells, using both direct fluorescence with fluorescein isothiocyanate-labeled tat and indirect immunofluorescence assays. This interaction was investigated with electrophysiology using isolated excitable frog muscle fibers and cockroach giant interneuron synapses. tat acted on the cell membrane and induced a large depolarization, accompanied by a decrease in membrane resistance, thereby modifying cell permeability. The neurotoxicity of tat was further demonstrated in vitro, on glioma and neuroblastoma cell growth, as well as by a 51Cr release assay in both tumor cell lines. Interestingly, no hemolytic activity of tat for human erythrocytes was found even when tat was tested at its highly neurotoxic concentration. Experiments in vivo showed that synthetic tat is a potent and lethal neurotoxic agent in mice. The use of tat peptide derivatives showed that basic region from 49 to 57 is necessary and sufficient for binding to cell membranes and toxicity.
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PMID:Evidence for neurotoxic activity of tat from human immunodeficiency virus type 1. 189 74

The CD4 antigen has been subverted as a receptor by the human and simian immunodeficiency viruses (HIV-1, HIV-2 and SIV). Several groups have reported that recombinant, soluble forms of the CD4 molecule (sCD4) block the infection of T lymphocytes by HIV-1, as CD4 binds the HIV envelope glycoprotein, gp120, with high affinity. We now report that sCD4 blocks diverse strains of HIV-1, HIV-2 and SIV, but is less effective for HIV-2. The blocking effect is apparent even after adsorption of virions to CD4 cells. Soluble CD4 prevents HIV infection of T-lymphocytic and myelomonocytic cell lines, but neither sCD4 nor anti-CD4 antibodies inhibit infection of glioma and rhabdomyosarcoma cell lines.
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PMID:Soluble CD4 blocks the infectivity of diverse strains of HIV and SIV for T cells and monocytes but not for brain and muscle cells. 253 42

In this paper we present the results of post-mortem examinations of the central nervous system in 61 male patients who died with Acquired Immunodeficiency Syndrome (AIDS); it includes 23 patients with reported neurological abnormalities at the time of presentation. The analysis revealed central nervous system (CNS) neoplasms (lymphoma, Kaposi's sarcoma) and a variety of inflammatory lesions (bacterial, fungal, protozoal and viral) in 32 cases. A total of 11 patients without opportunistic infections showed significant brain abnormalities characterized by microglial nodules and/or multinucleated giant cells, changes which are probably related to infection by human immunodeficiency virus (HIV). In addition, we describes results from a series of experiments designed to define the target cell population of HIV in the brain. The expression of CD4 complex--putative receptor for HIV--was investigated using short-term cultured brain cells taken from embryonic brain anlage and from different regions of fetal brain; glioma cells were also used. Cells derived from normal embryonic and fetal brain, as well as glioma cells, were examined with respect to their susceptibility to HIV. CD4 antigen expression could be demonstrated only on glioma cells of the permanent glioma line 85HG-59 comprised of cells with properties characteristic of astrocytes. Nevertheless, normal embryonic and fetal brain cells as well as glioma cells could be infected by HIV as documented by immunocytochemical methods and southern blot analysis. HIV infected brain cells showed reduced growth rate and altered growth pattern. This study emphasizes the diversity of HIV conditioned CNS impairments, suggesting that genomic variability of HIV may result in varying cell type preference of the virus. The experimental data indicate that CD4 expression in brain cells is probably not 'conditio sine qua non' for HIV susceptibility. The alterations of HIV-infected brain cells demonstrated provide further evidence for a direct involvement of HIV in the pathogenesis of AIDS-related neurological syndromes.
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PMID:Evaluation of intracerebral lesions in patients with acquired immunodeficiency syndrome. Neuropathological findings and experimental data. 274 42

Recently it has become evident that "second growth factor" of growth hormone (GH), such as somatomedins, has an effect on the proliferation and growth of tumor cells derived from nervous tissue. Effects of host-immunocompetence and the host-humoral states on the take incidence and proliferative activity of brain tumor cells were studied using two animal models: nude mouse and pituitary Snell dwarf mouse. Nude mouse is known to be immunodeficient. Pituitary Snell dwarf mouse is characterized by lack of circulating GH, TSH, prolactin, in addition to immunodeficiency. Cell line used in this experiment was C-6 cell of rat glioma cell. After intracranial implantation of C-6 glioma cells in the animals, the take incidence and growth rate of C-6 glioma cells were followed up and measured over a period of 2 months. Tissues of implants were studied immunohistochemically and biochemically. Regardless of cell line, successful take incidence in the different animal species was found to be greater in the descending order of nude mouse, dwarf mouse. This confirmed the role of immune status for the successful take of iso-, or heterologous tumor cells after implantation. We are now investigating the effect of exogenous GH on the growth rate of cells implanted in the dwarf mouse. This may clarify the effect of growth factors on proliferative activity of implanted tumor cells.
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PMID:[The correlation of host-immunocompetence and host-humoral states to the take incidence and proliferative activity of implantation C-6 glioma cells]. 276 6

The biologic, serologic, and molecular properties of isolates of human immunodeficiency virus type 1 (HIV-1) from the central nervous system (CNS) were determined and compared to those of isolates from peripheral blood and lymph nodes. Among these were pairs of CNS and blood isolates obtained from six infected individuals. The data show that HIV-1 isolates from the CNS can be distinguished from peripheral blood isolates by their (i) relative inability to infect established T-cell lines, (ii) reduced cytopathogenicity, (iii) inability to modulate CD4 antigen expression on infected cells, (iv) efficient replication in peripheral blood macrophages, and (v) insensitivity to serum neutralization. Paired CNS and peripheral blood isolates from the same individual also display some differences in cellular tropism. The blood isolates replicate better in T-cell lines and glioma cell lines, whereas the paired CNS isolates replicate more efficiently in primary macrophages. These results suggest that viruses isolated from the CNS of infected individuals may represent a specific HIV-1 subgroup.
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PMID:Isolates of human immunodeficiency virus type 1 from the brain may constitute a special group of the AIDS virus. 281 13


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