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

Monoclonal antibodies (MAbs) against the alpha- and beta-chain of lymphocyte-associated antigen-1 (LFA-1) were examined for inhibition of HIV-1 infection in vitro. Infection of the T cell line MT4 and the monocytic cell line U937 by isolates HTLVIIIB and SSI-002, respectively was inhibited in a concentration dependent manner by MAb against the beta-chain but not against the alpha-chain. No cross-reactivity was found between MAb against LFA-1 and against the CD4 receptor (MAb Leu3a). MAbs against the beta-chain and the CD4 receptor were found to act synergistically in inhibiting HIV infection. These data indicate that the beta-chain of LFA-1 in addition to the CD4 receptor may be involved in HIV infection in vitro.
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PMID:Involvement of lymphocyte function-associated antigen-1 (LFA-1) in HIV infection: inhibition by monoclonal antibody. 167 71

Polyhydroxycarboxylates (MW: 3,800-14,000) derived from phenolic (PDP) compounds have been found to inhibit the cytopathicity of HIV-1 and HIV-2 in MT-4 cells at concentrations that are not toxic to the host cells. The PDP compounds also inhibited syncytium formation in cocultures of MOLT-4 cells with HIV-1- or HIV-2-infected HUT-78 cells. They also interfered with the binding of OKT4A/leu3a monoclonal antibody (mAb) to the CD4 receptor, the binding of anti-gp120 mAb to HIV-1 gp120, and attachment of HIV-1 virions to MT-4 cells. The anti-HIV activity in this series of compounds can be ascribed to inhibition of the gp120-CD4 interaction and seems to depend on the presence of the anionic carboxylate groups. Their mechanism of action is similar to that of the heterogeneous polymer aurintricarboxylic acid (ATA).
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PMID:Selective inhibitory activity of polyhydroxycarboxylates derived from phenolic compounds against human immunodeficiency virus replication. 167 77

The ultimate consequence of infection with HIV is profound immunosuppression that is the result of both quantitative and qualitative abnormalities of the helper/inducer subset of T lymphocytes. The initial pathogenic event in HIV infection is binding of the envelope glycoprotein of HIV to the CD4 receptor molecule present on the surface of CD4+ T lymphocytes and monocyte/macrophages. In vivo the reservoir for HIV infection in the peripheral blood is the CD4+ T cell, whereas in other tissues the monocyte/macrophage may play a substantial role. As disease progresses in HIV-infected individuals, the viral burden in the peripheral blood CD4+ T cells increases. An understanding of the mechanisms involved in the transition from an initially low viral burden during the asymptomatic phase of HIV infection to the higher levels of virus expression detected in late stage disease is being investigated intensively. A number of potential agents that may influence regulation of HIV expression have been identified including mitogens, antigens, heterologous viruses, cytokines, and physical factors. The pathogenic mechanisms of HIV-induced neurologic abnormalities and the potential role of HIV in a number of other clinical manifestations of HIV infection are also discussed.
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PMID:Immunopathogenesis of HIV infection. 167 89

A novel membrane-bound serine esterase, named tryptase TL2, which is immunologically reactive with the antibody inhibiting induction of syncytia by human immunodeficiency virus-1 (HIV-1) (HATTORI, T., KOITO, A., TAKATSUKI, K., KIDO, H., and KATUNUMA, N., 1989, FEBS Lett., 248, 48-52), has been purified from a human T4+ lymphocyte clone. The enzyme has a molecular mass of 198 +/- 15 kDa, and is composed of two subunits of 32 kDa and four subunits of 28 kDa. The enzyme was strongly inhibited by the envelope glycoprotein gp120 of HIV-1, by synthetic peptides of V3 domains of gp120 s with the sequence GPGR in their center, which correspond to the principal neutralizing epitopes of the gp120s of various HIV-1 strains, by Kunitz-type inhibitors with the sequence GPCR in their active site, such as trypstatin, H130, and [Arg15, Glu52] aprotinin and by the microbial inhibitors leupeptin and antipain. This enzyme was specifically bound to the inhibitor V3 domain of gp120 of HIV-1, and this binding was blocked by the inhibitors of tryptase TL2, with a central motif GPCR or GPGR sequence in their center, but not by leupeptin and antipain without the motif. These findings suggest that tryptase TL2 is important in target site recognition and binding of HIV-1 in co-operation with CD4 receptor in the initial process of HIV-1 infection.
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PMID:A novel membrane-bound serine esterase in human T4(+)-lymphocytes is a binding protein of envelope glycoprotein gp120 of HIV-1. 168 71

Human immunodeficiency virus type-1 (HIV-1) and human T-cell leukemia virus type-I (HTLV-I) have a similar tropism for target cell types, especially for CD4+ T cells. In this study, we provide evidence that receptors of these two viruses exist independently on the target cell. We established an HTLV-I-producing CD8+ T cell line (ILT-8M2) with a remarkable cell fusion capacity. When cocultured with MOLT-4 cells, ILT-8M2 cells induced giant syncytia more efficiently than any other tested HTLV-I-producer cell lines. In contrast to other HTLV-I-producers, ILT-8M2 cells were minimally susceptible to cytopathic effects of HIV-1 due to very low expression of CD4, although they were able to be persistently infected by HIV-1. The indicator MOLT-4 cells are known to respond well to HIV-1-induced cell fusion, but they lose this ability if they become persistently infected with HIV-1 because of the reduction of CD4 receptor expression. ILT-8M2 was, however, still capable of inducing syncytia with the MOLT-4 cells persistently infected by HIV-1 (MOLT-4/IIIB). This syncytium formation was dependent on the HTLV-I-envelope, as it was inhibited by HTLV-I-positive human sera or a monoclonal antibody to HTLV-I gp46 but not by monoclonal antibodies to HIV-1 gp120 or CD4. Moreover, ILT-8M2 cells persistently infected by HIV-1 (ILT-8M2/IIIB) induced both HTLV-I- and HIV-1-mediated syncytia with uninfected MOLT-4 cells. These results suggest that HTLV-I induces cell fusion utilizing receptors on the target cells independent of HIV-1-receptors.
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PMID:Coexistence of fusion receptors for human T-cell leukemia virus type-I (HTLV-I) and human immunodeficiency virus type-1 (HIV-1) on MOLT-4 cells. 168 90

The transmission of HIV requires the interaction of the cell-surface CD4 receptor and the viral envelope glycoprotein. Experiments were performed to determine the role of other cell-surface molecules in the development of HIV-induced syncytia. Although CEM and MT-2 cells had similar cell-surface CD4 receptor densities, less than 1% of CEM cells and greater than 95% of MT-2 cells formed syncytia with H9 cells chronically infected with HIV-1 (H9-IIIB). When compared with CEM cells, MT-2 cells exhibited a 10-fold and threefold greater capacity to form homotypic and heterotypic conjugates with H9 cells, respectively. Increasing the conjugate formation capacity of CEM cells with the lectin wheat germ agglutinin led to a greater than 30-fold increase in the formation of syncytia with H9/IIIB cells. The formation of syncytia between MT-2 and H9/IIIB cells was magnesium-, energy-, temperature-, and actin-cytoskeleton-dependent, and could be inhibited (65%) by an anti-LFA-1 monoclonal antibody. The combination of anti-leukocyte function-associated antigen-1 (LFA-1) and anti-CD2 monoclonal antibodies resulted in a synergistic inhibition (89%) of syncytium formation. These results indicate that integrins and other cell-surface adhesion molecules regulate HIV-induced syncytium formation.
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PMID:HIV-induced syncytium formation requires the formation of conjugates between virus-infected and uninfected T-cells in vitro. 168 45

Human choriocarcinoma cells of the JAR line, with no demonstrable surface CD4 receptor were infected with human immunodeficiency virus type 1 (HIV-1), strain RF. Primer-directed enzymatic DNA amplification (polymerase chain reaction, PCR) detected the presence of viral DNA when the cultures were investigated at day 5 post-infection (p.i.). The absence of cytopathic changes attributable to virus replication suggested silent infection of these malignant trophoblastic cells. Neither reverse transcriptase (RT) activity nor HIV-specific antigens were found in the culture nutrient medium during JAR cell propagation. However, when the HIV-carrier JAR cells were continuously cultured and the cocultivation was initiated with CEM-SS lymphoblastoid cells after two subsequent passages, rescue of infectious virus was observed.
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PMID:In vitro productive infection of human malignant trophoblastic cell line JAR with human immunodeficiency virus type 1 (HIV-1). 168 80

Multinucleated giant cell (syncytium) formation induced by the interaction between the gp120 glycoprotein expressed on the surface of cells infected with human immunodeficiency virus type (HIV-1) and the CD4 receptor of uninfected CD4-positive (CD4+) cells may play an important role in the depletion of T4 lymphocytes in acquired immune deficiency syndrome (AIDS) patients. Using a double fluorescence cell-staining technique and analysis of the cells by the fluorescence-activated cell sorter (FACS), we have demonstrated that giant cell formation between persistently HIV-1-infected HUT-78 cells and uninfected MOLT-4 cells results in a selective destruction of the uninfected CD4+ MOLT-4 cells. Apparently, bystander CD4+ cells may serve as targets for the killing effect of the HIV-1-infected cells, and this killing effect is preceded by fusion between the target (uninfected) and aggressor (infected) cells. Pentosan polysulfate, dextran sulfate, and various other sulfated polysaccharides, but not heparin, have proved to inhibit this cell fusion process and hence protect the target CD4+ cells against destruction by the killer HIV-1-infected cells. Azidothymidine does not interfere with this process. Assuming that fusion between HIV-infected and uninfected CD4+ cells is a crucial event in the pathogenesis of AIDs, any compounds that specifically interfere with this process may be therapeutically advantageous in the treatment of this disease.
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PMID:Sulfated polysaccharides as potent inhibitors of HIV-induced syncytium formation: a new strategy towards AIDS chemotherapy. 169 Dec 88

Eighty to 100% of persistently HIV-1-infected HUT-78 cells express the viral glycoprotein gp120 as demonstrated with anti-gp 120 monoclonal antibody (mAb) and fluorescence-activated cell sorter (FACS) analysis. Several polyanionic anti-HIV compounds, i.e., dextran sulfate, pentosan polysulfate, heparin, aurintricarboxylic acid (ATA), suramin, and Evans blue, which are known to inhibit the adsorption of HIV particles to CD4+ cells, prevented the binding of anti-gp120 mAb to the persistently HIV-1 infected HUT-78 cells. This effect was dose-dependent and reversible. Except for ATA, the polyanionic compounds did not interfere with the binding of Leu3a/OKT4A mAB, indicating that they do not directly bind to the CD4 receptor. Thus, the inhibitory effect of dextran sulfate and its congeners on the interaction of the HIV gp120 with the cellular CD4 receptor can be ascribed to a specific binding ("shielding") of gp120.
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PMID:Dextran sulfate and other polyanionic anti-HIV compounds specifically interact with the viral gp120 glycoprotein expressed by T-cells persistently infected with HIV-1. 169 63

Syncytium formation between HUT-78 cells persistently infected with human immunodeficiency virus type 1 (HIV-1) and uninfected CD4-bearing MOLT-4 or CEM cells results in a rapid destruction of the MOLT-4 or CEM cells. This syncytium formation is due to the interaction between the gp120 glycoprotein expressed by the persistently HIV-1-infected HUT-78 cells and the CD4 receptor present on MOLT-4 or CEM cells. A flow cytometric method has been applied to separate the infected (HUT-78) from the uninfected (MOLT-4, CEM) cell populations. This method is based on a modified DNA staining protocol which clearly shows the differences in DNA content between HUT-78 cells, on the one hand, and MOLT-4 or CEM cells, on the other hand. Using this flow cytometric method we have demonstrated that those compounds (i.e., sulfated polysaccharides, aurintricarboxylic acid) that interact with gp120 (of the HIV-infected cells) or CD4 (of the uninfected cells) suppress syncytium formation and concomitant destruction of the CD4+ cells.
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PMID:Flow cytometric method to monitor the destruction of CD4+ cells following their fusion with HIV-infected cells. 169 39


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