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: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Since clinical trials are being planned with the immunomodulating drug isoprinosine combined with the antiviral drug 3'-azido-3'-deoxythymidine (AZT) in patients with acquired immunodeficiency syndrome (AIDS) and AIDS-related complex, it is important to determine the type of antiviral interaction produced by these drugs in vitro. Such a combined modality may not only produce enhanced antiviral effects but also may have a valuable immunorestorative action. The interaction of several ratios of AZT and isoprinosine on the replication of human immunodeficiency virus type 1 in human peripheral blood mononuclear cells was determined by reverse transcriptase assay of disrupted virus obtained from supernatants of cells that were exposed to virus and the drugs separately and in combination and by a human immunodeficiency virus type 1 p24 enzyme immunoassay of the same supernatants. The correlation between the reverse transcriptase and enzyme immunoassay data was high. The antiviral activity of AZT alone was neither diminished nor augmented when AZT was used in combination with isoprinosine. Isoprinosine did not enhance virus yield when used alone or in combination with AZT in peripheral blood mononuclear cells, nor did it affect the growth of uninfected cells. The in vitro results indicate that this combination did not decrease the efficacy of AZT or exacerbate virus replication.
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PMID:Combinations of isoprinosine and 3'-azido-3'-deoxythymidine in lymphocytes infected with human immunodeficiency virus type 1. 246 87

Methisoprinol (isoprinosine) is a synthetic compound with reported antiviral and immunomodulating properties. Results of the present study showed that methisoprinol at concentrations greater than or equal to 200 micrograms/ml reduces the p24 and gp120 viral antigen expression on the surface of human immunodeficiency virus (HIV)-infected lymphocytes and the reverse transcriptase levels. In addition, cell viability, the number of the CD4+ cells, and the CD4+/CD8+ cell ratio are higher in methisoprinol-pretreated cell suspensions than in untreated HIV-infected cell cultures. A quantitative freeze-fracture study on the density of the intramembranous particles (IMP) present on both fracture faces of the plasma membrane of lymphocytes has shown that pretreatment with methisoprinol induces a different molecular organization resulting in a nearly three times increase of IMP density.
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PMID:Influence of methisoprinol (isoprinosine) on HIV-infected human lymphocytes: in vitro immunological, virological, and ultrastructural studies. 246 81

The addition of monosialoganglioside GM1 to serum-free culture medium efficiently and specifically inhibited CD4 antigen expression on normal T lymphocytes from peripheral blood or thymus as well as on cells from H9 and Molt-3 lines; other molecules such as CD3, CD2 and CD8 were not affected. Subsequent addition of fetal calf serum or bovine and human serum albumin blocked GM1 action on CD4 expression, most likely through the formation of ganglioside-albumin complexes. Removal of GM1 from the medium was followed by the prompt reappearance of CD4 on the cell surface. GM1 treatment of H9 and Molt-3 cells greatly reduced HIV-1 infectivity, which was evaluated by reverse transcriptase activity levels in culture supernatants and p24 detection on target cells. GM1 also inhibited syncytial formation in Molt-3 cells even when treatment was initiated 24h after infection. The GM1 effect on HIV-1 infectivity, however, was not long-lasting since removal of the compound was followed by a rapid increase in viral replication, probably due to CD4 re-expression and HIV-1 propagation from a few initially infected cells.
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PMID:CD4 modulation and inhibition of HIV-1 infectivity induced by monosialoganglioside GM1 in vitro. 247 63

Infectious retrovirus particles consist of a core structure containing RNA and gag-pol polypeptides surrounded by a lipid membrane studded with env proteins. A recombinant vaccinia virus was designed to express the entire gag-pol precursor protein of the human immunodeficiency virus type 1. Synthesis and processing of gag proteins occurred in mammalian cells infected with this live recombinant virus, and reverse transcriptase was detected largely in the medium. Electron micrographs revealed immature retrovirus-like particles budding from the plasma membrane and extracellular particles with morphological characteristics of immature and mature human immunodeficiency virus. The latter contained functional reverse transcriptase as well as processed p24 and p17 gag polypeptides. Thus, assembly and maturation of human immunodeficiency virus-like particles can occur in the absence of either infectious RNA molecules or env proteins. The production of noninfectious virus-like particles by expression vectors should be useful for biochemical studies and could provide a safe source of material for the development of vaccines.
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PMID:Human immunodeficiency virus-like particles produced by a vaccinia virus expression vector. 247 31

We have examined 3 different EBV-carrying B cell lines, in terms of ability to be super-infected by the human immunodeficiency virus (HIV-1), and have followed these lines, after infection by HIV-1, over a period of 3 months. We found significant variation among different HIV-1 strains in terms of the multiplicity of infection required to initiate infection in these EBV-positive cell lines. Persistent infection by HIV-1 in the absence of detectable cytopathic effects could be demonstrated, as evaluated by a variety of techniques, including reverse transcriptase assay and immunofluorescence. The results indicate also that all of these cell lines produced progeny HIV-1 intermittently, with large amounts of virus production on some days but not others. In contrast, they were all able to continuously express p24.
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PMID:Susceptibility of EBV-carrying B cell lines to infection by HIV-1: variability of production of progeny virus and expression of viral antigens. 247 62

Two monoclonal antibodies (Mabs) reacting with different epitopes of the human immunodeficiency virus type 1 core protein p24 (HIV p24) were used either singly or in combination as tracers in enzyme-linked immunosorbent assays. The culture supernatant of 215 samples of peripheral blood mononuclear cells from 112 patients were measured for HIV p24 and reverse transcriptase (RT) activity during cultivation. One hundred forty-one cultures were positive for HIV p24 and 122 for RT after 32 days of cultivation. After 8-9 days, HIV p24 was detected in 50.4% and RT in 27.8% of the cultures later judged as HIV positive. Two patients seemed to have substrains of HIV-1 not reactive with one of the Mabs.
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PMID:Human immunodeficiency virus type 1 p24 production and antigenic variation in tissue culture of isolates with various growth characteristics. 248 39

A mild heat-shock (10 min at 44 degrees C), performed just before seeding on healthy PBL used for co-cultivation, allows the detection of viral markers (p24 core antigen and reverse transcriptase) in a very short time. This suggests that heat-shocked PBL can be employed routinely for the rapid detection of HIV-1 in clinical samples.
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PMID:Rapid detection of HIV-1 in clinical samples by co-culture with heat-shocked cells. 248 42

MT-4 cells persistently infected with human immunodeficiency virus type 1 (HIV-1) (MT-4/HIV-1) were recently isolated (K. Ikuta, C. Morita, M. Nakai, N. Yamamoto, and S. Kato, Japan. J. Cancer Res. (Gann), 79, 418-423, 1988). Mouse hybridoma cell clones producing monoclonal antibodies (MoAbs) to HIV-1 gag p24 and p18, and pol reverse transcriptase (RT) were isolated by using this MT-4/HIV-1 cell line for the screening of MoAb production by the immunofluorescence (IF) test. By indirect IF tests of acetone-fixed cells with these MoAbs, the IF intensities in MT-4/HIV-1 cells were found to be higher than those in the other HIV-1 infected cells, such as MOLT-4/HIV-1, HL-60/HIV-1, and U937/HIV-1 cells. Cell surface expression of the HIV-1 gag p24 and p18 antigens examined by IF and radioimmune techniques with these MoAbs revealed the p24 and p18 antigens to be expressed strongly on the cell surface of MT-4/HIV-1 cells and faintly on the cell surface of MOLT-4/HIV-1 cells, respectively. However, monoclonal antibody isolated in the present study failed to detect pol RT antigen on the surface of MT-4/HIV-1 cells. These results indicate that the gag p24 and p18 antigens are expressed, at least in part, on the surface of HIV-1-infected cells.
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PMID:Expression of human immunodeficiency virus type 1 (HIV-1) gag antigens on the surface of a cell line persistently infected with HIV-1 that highly expresses HIV-1 antigens. 249 13

Three enzyme immunoassay (EIA) methods for the detection of human immunodeficiency virus (HIV-1) were evaluated. Serum or plasma samples from 22 individuals seropositive for HIV-1 antibodies were tested with the Abbott, Coulter, and DuPont kits for presence of HIV-1 p24 antigen. Another 12 samples were tested with two kits only. Discordant results were obtained with 9 of 34 (26%) HIV-1-antibody-positive patient samples tested. Most of these discrepancies were found in samples containing less than 30 pg/ml of HIV-1 p24 core antigen. A sampling of sera from normal blood donors and patients with infectious or autoimmune diseases revealed a low level of false positive reactions, especially with sera containing antinuclear antibodies or rheumatoid factor. Noteworthy is the frequency of false positive reactions seen with the DuPont EIA for HIV-1 p24 antigen. 18/111 sera (16.2%) containing auto-antibodies tested positively with the DuPont HIV-1 p24 antigen EIA. The nonspecific nature of the test reactivity for 9/10 of these samples was confirmed using an HIV-1 p24 antigen inhibition assay. These findings are discussed in light of the need for HIV-1 antigen detection in the clinical laboratory and of other methods for HIV-1 detection: the polymerase chain reaction and measurements of reverse transcriptase activity.
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PMID:Evaluation of three enzyme immunoassays for HIV-1 antigen detection. 251 47

Calves were immunised by means of a native Al(OH)3-absorbed gp51-preparation which had been obtained from a foetal lamb kidney cell line, following bovine leucosis virus (BLV) infection. 9 animals were immunised 3 times, using 300 micrograms gp51. 7 animals underwent test infection, using 2.5 x 10(3) or 2.5 x 10(4) BLV-infected lymphocytes. Serological and virological reactions of all animals, including 3 calves which had received only test infections, were followed up through 40 weeks by means of immunodiffusion test, enzyme-immuno-assay, gp51 antibody radio-immuno-assay, reverse transcriptase test, syncytial test, competitive p24 radio-immuno-assay, and by transmission of whole blood in animal experiments. The results obtained from virological testing showed that 1 animal had been protected by preceding immunisation. 4 in 7 immunised and test-infected animals exhibited transient BLV values, between the 7th and 16th weeks from infection. Typical leucosis infection had been induced to 2 animals. The above findings are discussed and are compared to similar results recorded by other working groups.
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PMID:[Immunization of young cattle with gp51 of the bovine leukosis virus and the subsequent experimental infection]. 255 73


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