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

Tumor necrosis factor-alpha (TNF-alpha) induces the expression of human immunodeficiency virus type-1 (HIV-1) in vitro in chronically infected cells of T and monocytic origin. The tat protein from the HIV-1 virus has been shown to be essential for HIV replication and in the immunosuppression associated with the virus infection. Previous studies in our laboratory have shown that HIV-1 tat gene induces TNF-beta (lymphotoxin) in human B-lymphoblastoid cells (Sastry et al., 1990, J. Biol. Chem. 265, 20091-20093). In an attempt to characterize further the relationship between the host and HIV-1, we investigated the effect of the functional HIV-1 tat gene on the expression of TNF receptors in a human B lymphoblastoid cell line (Raji). We report here that Raji cells transfected with HIV-1 tat gene express fewer cell surface TNF receptors than control cells. At least a 5-fold decrease in the receptor number without any significant change in receptor affinity was observed. The decrease in TNF receptors in tat-transfected Raji cells (Raji-tat cells) was found not to be due to receptor occupancy by the autocrine production of TNF-beta. The decrease in the cell surface expression of TNF receptors in Raji-tat cells was also found to be not due to a decrease in the gene expression of the receptor. The kinetics, amount of TNF binding and its internalization were temperature dependent, and it was different in Raji-tat cells than in the control cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Down-modulation of cell surface expression of p80 form of the tumor necrosis factor receptor by human immunodeficiency virus-1 tat gene. 133 62

Human immunodeficiency virus (HIV) infection of brain macrophages and astroglial proliferation are central features of HIV-induced central nervous system (CNS) disorders. These observations suggest that glial cellular interactions participate in disease. In an experimental system to examine this process, we found that cocultures of HIV-infected monocytes and astroglia release high levels of cytokines and arachidonate metabolites leading to neuronotoxicity. HIV-1ADA-infected monocytes cocultured with human glia (astrocytoma, neuroglia, and primary human astrocytes) synthesized tumor necrosis factor (TNF-alpha) and interleukin 1 beta (IL-1 beta) as assayed by coupled reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay, and biological activity. The cytokine induction was selective, cell specific, and associated with induction of arachidonic acid metabolites. TNF-beta, IL-1 alpha, IL-6, interferon alpha (IFN-alpha), and IFN-gamma were not produced. Leukotriene B4, leukotriene D4, lipoxin A4, and platelet-activating factor were detected in large amounts after high-performance liquid chromatography separation and correlated with cytokine activity. Specific inhibitors of the arachidonic cascade markedly diminished the cytokine response suggesting regulatory relationships between these factors. Cocultures of HIV-infected monocytes and neuroblastoma or endothelial cells, or HIV-infected monocyte fluids, sucrose gradient-concentrated viral particles, and paraformaldehyde-fixed or freeze-thawed HIV-infected monocytes placed onto astroglia failed to induce cytokines and neuronotoxins. This demonstrated that viable monocyte-astroglia interactions were required for the cell reactions. The addition of actinomycin D or cycloheximide to the HIV-infected monocytes before coculture reduced, > 2.5-fold, the levels of TNF-alpha. These results, taken together, suggest that the neuronotoxicity associated with HIV central nervous system disorders is mediated, in part, through cytokines and arachidonic acid metabolites, produced during cell-to-cell interactions between HIV-infected brain macrophages and astrocytes.
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PMID:Cytokines and arachidonic metabolites produced during human immunodeficiency virus (HIV)-infected macrophage-astroglia interactions: implications for the neuropathogenesis of HIV disease. 146 Apr 27

The tat protein from human immunodeficiency virus type 1 (HIV-1) activates viral gene expression and is essential for HIV replication in vitro. It has also been shown that the tat gene product specifically inhibits antigen-induced proliferation of human peripheral blood lymphocytes. In order to understand the growth and immunomodulatory roles of HIV-1 tat, we have examined the effect of the tat gene on the expression of tumor necrosis factors in a human B-lymphoblastoid cell line (Raji). We report here that the HIV-1 tat gene introduced into Raji cells by retroviral-mediated transformation induces production of tumor necrosis factor-beta (TNF-beta). The tat-mediated induction of TNF-beta seems to be both at the transcriptional and post-transcriptional levels because, concurrent with a 30-fold increase in the levels of TNF-beta protein, an approximate 8-fold increase in mRNA was observed in tat-transformed Raji cells. It is recently reported that tat protein of HIV-1 stimulates growth of cells derived from Kaposi's sarcoma lesions of AIDS patients (Ensoli, B., Barillari, G., Salahuddin, S.Z., Gallo, R.C., and Wong-Staal, F. (1990) Nature 345, 84-86). Since TNF has been shown to function as a growth factor for several cell types, our results showing induction of TNF-beta by tat indicate the possibility that a growth-stimulatory role of HIV-1 tat on Kaposi's sarcoma cells is mediated through TNF-beta.
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PMID:HIV-1 tat gene induces tumor necrosis factor-beta (lymphotoxin) in a human B-lymphoblastoid cell line. 224 81

The production of tumor necrosis factor (TNF)-alpha and TNF-beta by various human hematopoietic cell lines was quantitatively examined using a highly sensitive radioimmunoassay specific to TNF-alpha, or a cytolytic assay performed with mouse L929 cells. It was found that the HTLV-1-infected T cell lines examined produced large amounts of both TNF-alpha and TNF-beta. In particular, interleukin-2 (IL-2)-dependent cell lines produced large amounts of TNF-alpha. In contrast, human cell lines not infected with HTLV-1 essentially did not produce either of the TNFs. It was also found that the high production of TNF-alpha by HTLV-1-infected cells partially correlated to their high sensitivity to human immunodeficiency virus (HIV) infection. Treatment of MT-4 cells, one of the most HIV-sensitive HTLV-1-infected cell lines, with antibody specific to TNF-alpha reduced their sensitivity to HIV infection.
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PMID:Production of tumor necrosis factors by human T cell lines infected with HTLV-1 may cause their high susceptibility to human immunodeficiency virus infection. 235 83

We have studied the pattern of expression of the lymphokines tumor necrosis factor (TNF alpha) and lymphotoxin (TNF beta) in T-cell lines established by transformation with human T-lymphotropic virus, type I (HTLV-I), the etiologic agent of adult T-cell leukemia (ATL). We report here that nine of nine HTLV-I-infected T-cell lines, established by in vitro infection with HTLV-I, including those with CD4+ or CD8+ as well as CD4-/CD8- phenotypes, constitutively produce high levels of TNF alpha and -beta mRNA and secrete biologically active TNF beta into the culture medium. Similar patterns of expression are seen in six of six HTLV-I-infected T-cell lines directly established from ATL patients. In contrast, several T-cell lines, either uninfected or infected with human immunodeficiency virus I, did not produce comparable levels of the TNF beta. Comparisons of a normal functional T-cell clone before and after infection with HTLV-I show that expression of TNF beta mRNA is induced in the infected cells. The high level expression in HTLV-I-infected cell lines dose not seem to involve perturbation of the TNF alpha/beta genetic loci by proviral integration. A cell line (81-66/45) nonproductively transformed with HTLV-I that produces tat-1 in the absence of viral structural proteins, produces both TNF alpha and -beta mRNA. This suggests that expression of these cytokines could be mediated in trans by the tat-1 gene product.
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PMID:Human T-lymphotropic virus I-infected T cells constitutively express lymphotoxin in vitro. 278 72

Retroviral infections are accompanied by immunosuppression in a variety of species. For feline leukemia virus, the immunosuppression has been ascribed to the transmembrane envelope protein, p15E, which suppresses the proliferative responses of cat, mouse, and human lymphocytes. A similar suppressive effect has been shown for a lysate of human immunodeficiency virus (HIV), strain HTLV-IIIB. Here we determined that detergent-disrupted HTLV-IIIB lystate exerted a strong suppressive effect on PHA-stimulated lymphocytes. Preparations of whole virions, a lysate of a local HIV isolate grown on MP-6 cells, and a commercially obtained UV and psoralene-inactivated lysate were examined and demonstrated to have a similar suppressive effect. The HIV lysate was not directly cytotoxic to lymphocytes and did not contain tumor necrosis factor or lymphotoxin. The HIV lysate specifically suppressed the proliferation of a range of hemopoietic cell lines from man and mouse including three EBV transformed CD4- and IL-2 receptor-negative B-cell lines. The lysate also suppressed the formation of human bone marrow colonies, whereas the lysate had only a slight or no effect on fibroblasts. The suppression of lymphocyte proliferation was not abrogated by addition of IL-2 or IL-1 and the HIV lysate inhibited the expression of IL-2 receptors on suboptimal PHA-stimulated mononuclear cells. The suppressive factor(s) has not been characterized in molecular terms, but suppressive activity was recovered in fractions with a molecular weight of about 67,000 and in both the glycoprotein fraction and in the glycoprotein-depleted fraction of the HIV lysate. Sera from one-third of a small series (N = 13) of individuals with antibodies to HIV seem to be able to neutralize the suppressive properties of HIV lysate in cultures.
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PMID:Investigation of immunosuppressive properties of inactivated human immunodeficiency virus and possible neutralization of this effect by some patient sera. 278 62

The effect of culture supernatant of MT-2 cells on human immunodeficiency virus (HIV)-producing cells, MOLT-4/HIVHTLV-IIIB cells, was examined. As compared to the effect on MOLT-4 cells, parent cells not infected with HIV, a selective cytotoxic/cytostatic effect on MOLT-4/HIVHTLV-IIIB cells was observed 4 days after treatment with up to 640-fold-diluted MT-2 supernatant. Furthermore, under similar conditions, a 2- to 6-fold increase in the number of HIV particles was detected in the culture of MOLT-4/HIVHTLV-IIIB cells 6 hr after treatment. Complete blocking of these effects by anti-lymphotoxin monoclonal antibody, but not by anti-tumor necrosis factor antibody, indicates that these effects of MT-2 supernatant on MOLT-4/HIVHTLV-IIIB cells are attributable to a lymphotoxin-related cytotoxic factor.
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PMID:Effect of culture supernatant of MT-2 cells on human immunodeficiency virus-producing cells, MOLT-4/HIVHTLV-IIIB cells. 313 Mar 48

The effect of natural lymphotoxin (n-LT) on CD4+ MOLT-4 cells and those cells producing human immunodeficiency virus (HIV), MOLT-4/HIVHTLV-IIIB cells, was studied. Four days after treatment with n-LT, a significant cytotoxic/cytostatic effect was observed predominantly on MOLT-4/HIVHTLV-IIIB cells. Furthermore, with regard to the production of HIV, an almost 3- to 5-fold increase of viral particles was observed in MOLT-4/HIVHTLV-IIIB cells 6 h after treatment with n-LT. These data indicate the possibility that this cytotoxic factor is one of the responsible molecules in the pathogenesis of the acquired immunodeficiency syndrome (AIDS).
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PMID:Enhancement of human immunodeficiency virus production by natural lymphotoxin. 326 93

We investigated the CD8+CD57+ alveolar cell functions and their immunoregulatory role in lungs from HIV-seropositive patients with the clinical presentation of lymphocytic alveolitis at different stages of human immunodeficiency virus (HIV) disease. We previously reported, at Stage IV of HIV infection, an expansion of CD8+CD57+ alveolar lymphocytes mirroring the decline of local anti-HIV cytotoxic T-lymphocyte (CTL) responses, and demonstrated that sorted CD8+CD57+ alveolar lymphocytes inhibited the effector phase of these HIV-specific CTL. In the present study, we show that the expansion of CD8+CD57+ alveolar T cells can also be detected at stages II and III of HIV disease, although at a lower degree than observed at Stage IV of HIV infection. When sorted, these CD8+CD57+ alveolar lymphocytes block effector killer cells such as allospecific CTL, natural killer (NK), and lymphokine-activated killer (LAK) cells. The mechanism of action of these inhibitory T-lymphocytes has been further studied and we demonstrated that: (1) cell-to-cell contact between inhibitor and killer is not required, (2) nonstimulated alveolar CD8+CD57+lymphocytes but not CD57- lymphocytes spontaneously release a solube inhibitor of cytolytic functions (ICF). This inhibitory activity of alveolar CD8+CD57+ cells is mediated by a glycosylated protein which is distinct from tumor necrosis factor-alpha (TNF alpha), TNF beta, transforming growth factor-beta 1 (TGF beta 1), TGF beta 2, interferon alpha (IFN alpha), interferon gamma (IFN gamma), and prostaglandins. The release of such an inhibitor of killer cell functions by CD8+CD57+ lymphocytes in the lungs, which are an important interface between the sterile body and the antigen-laden environment, may play a role in the local control of cell immunity.
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PMID:Alveolar CD8+CD57+ lymphocytes in human immunodeficiency virus infection produce an inhibitor of cytotoxic functions. 751 68

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


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