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)

Human retroviruses have been detected in supernatants of cultures of Ficoll-enriched lymphocytes from peripheral blood, lymph nodes and bone marrow of (a) 32 out of 42 patients with Acquired Immunodeficiency Syndrome (AIDS), (b) 34 out of 64 patients with AIDS-related Complex (ARC), (c) 9 out of 18 asymptomatic children born from Human Immunodeficiency Virus (HIV) seropositive mothers, and (d) 9 out of 28 asymptomatic drug abusers or hemophiliacs. Virus detection was monitored by assaying culture supernatants for the presence of Mg++-dependent reverse transcriptase (R.T.) activity. A number of these virus-positive sups were passaged repeatedly in cultures of phytohemagglutinin-stimulated and Interleukin-2 (IL-2) treated fresh lymphocytes from healthy blood donors. Occasionally, multiple samples were obtained at varying time intervals from the same patient and consistently yielded detectable retroviral activity. Several isolates were characterized as closely related if not identical to HIV, HTLV-IIIB strain, since cells from either patients' own lymphocyte cultures or subcultures infected with passaged virus were stained in an indirect immunofluorescent assay with both patients sera and monoclonal antibody against p24 antigen of the HTLV-IIIB strain. Representative isolates, grown on fresh lymphocytes of healthy donors and metabolically labelled with 35S-cysteine, were also analyzed in a radioimmunoprecipitation assay (RIPA) against patients' sera to define their antigenic pattern, which was widely superimposable to that obtained with HTLV-IIIB-infected H9 cells. DNA from lymphocytes infected with 2 representative isolates were Southern-blotted and probed with an insert from a plasmid containing the entire genome of the HTLV-IIIB strain. The hybridization patterns were comparable with those obtained with DNA from H9-infected cells.
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PMID:Recovery of HIV-related retroviruses from Italian patients with AIDS or AIDS-related complex and from asymptomatic at-risk individuals. 343 18

Drug susceptibility and mutations in the reverse transcriptase (RT) gene were analyzed with 167 virus isolates from 38 patients treated with nevirapine, a potent nonnucleoside inhibitor of human immunodeficiency virus type 1 (HIV-1) RT. Resistant isolates emerged quickly and uniformly in all patients administered nevirapine either as monotherapy or in combination with zidovudine (AZT). Resistance developed as early as 1 week, indicating rapid turnover of the virus population. The development of resistance was associated with the loss of antiviral drug activity as measured by CD4 lymphocyte counts and levels of HIV p24 antigen and RNA in serum. In addition to mutations at amino acid residues 103, 106, and 181 that had been identified by selection in cell culture, mutations at residues 108, 188, and 190 were also found in the patient isolates. Sequences from patient clones documented cocirculating mixtures of populations of different mutants. The most common mutation with monotherapy, tyrosine to cysteine at residue 181, was prevented from emerging by coadministration of AZT, which resulted in the selection of alternative mutations. The observations documented that, under selective drug pressure, the circulating virus population can change rapidly, and many alternative mutants can emerge, often in complex mixtures. The addition of a second RT inhibitor, AZT, significantly altered the pattern of mutations in the circulating population of HIV.
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PMID:Nevirapine resistance mutations of human immunodeficiency virus type 1 selected during therapy. 750

Macrophage activation resulting from phagocytosis has the potential to modulate human immunodeficiency virus (HIV) replication. We have determined the effects of phagocytosis of particulate stimuli on transcription and release of HIV. Using THP-1 and Mono Mac 6 human monocytic cell lines transfected with HIV long terminal repeat sequence chloramphenicol acetyltransferase (LTR CAT) constructs we have demonstrated that phagocytosis of Mycobacterium tuberculosis enhanced HIV-1 and -2 LTR CAT expression. However phagocytosis of zymosan or inert latex beads had little or no effect on CAT expression. Enhancement of HIV LTR CAT expression was dependent upon intact NF-kappa B binding sites and was independent of tumour necrosis factor alpha secretion. M. tuberculosis strains of different degrees of virulence induced similar levels of enhanced CAT expression. In contrast, phagocytosis of M. tuberculosis by HIV-1-infected THP-1 cells reduced supernatant reverse transcriptase (RT) activity without suppression of p24 antigen release. Phagocytosis of zymosan granules or latex particles did not alter released RT activity. However, phagocytosis of either M. tuberculosis, zymosan granules or latex particles by HIV-1-infected human peripheral blood monocyte-derived macrophages reduced supernatant RT activity. These data indicate that phagocytosis of M. tuberculosis may enhance HIV transcription in monocytic cells although it may reduce release of intact HIV.
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PMID:Phagocytosis of Mycobacterium tuberculosis modulates human immunodeficiency virus replication in human monocytic cells. 751 19

Combinations of the human immunodeficiency virus (HIV) Tat protein antagonist Ro 24-7429 with either the HIV protease inhibitor Ro 31-8959 or the HIV reverse transcriptase inhibitors AZT (3'-azido-3'-deoxythymidine), ddC (2',3'-dideoxycytidine), ddI (2',3'-dideoxyinosine), and nevirapine were synergistic or additive in reducing HIV type 1 p24 antigen production in CEM cells or inhibiting HIV type 1-induced syncytium formation in HT4-6C cells.
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PMID:Combinative interactions of a human immunodeficiency virus (HIV) Tat antagonist with HIV reverse transcriptase inhibitors and an HIV protease inhibitor. 751 58

Blood-derived macrophages were acutely infected with HIV and treated with a combination of leucocyte interferon (IFN) and five anti-HIV drugs. HIV growth was assayed by quantitation of p24 antigen in the supernatant and in some experiments by determination of reverse transcriptase activity. Both IFN and all drugs, with the exception of fusidic acid, inhibited HIV growth in a dose-dependent manner. IFN in combination with zidovudine, dideoxycytidine or fusidic acid exerted a synergistic effect on HIV titers, while IFN combined with dideoxyinosine or foscarnet had an additive effect.
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PMID:Anti-HIV activity of dideoxynucleosides, foscarnet and fusidic acid is potentiated by human leukocyte interferon in blood-derived macrophages. 751 81

A panel of monoclonal antibodies (mAbs) detecting distinct B-cell epitopes on p24 core viral protein of feline immunodeficiency virus (FIV) were employed to develop immunoassays to measure p24 concentration in culture and serum samples, to localize p24 in FIV-infected cells and tissues, and to detect anti-p24 antibodies in cat sera. In its optimized configuration the p24 capture assay detected as little as 0.25 ng/ml of protein. The assay was found at least as sensitive as the reverse transcriptase activity assay in FIV-infected lymphocyte cultures and proved capable of detecting p24 antigen in acid pretreated sera from a high proportion of FIV-infected cats. The mAbs were also successfully used to detect the p24 antigen in permeated FIV-infected cells by flow cytometry and in tissue sections from FIV-infected cats by immunohistochemical staining. Anti-p24 antibodies in FIV-infected cat sera were assayed by a competitive capture ELISA which readily identified occasional false positive results provided by a standard ELISA using purified whole FIV-coated wells.
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PMID:Detection of feline immunodeficiency virus p24 antigen and p24-specific antibodies by monoclonal antibody-based assays. 751 44

We have shown that umbilical cord blood mononuclear cells (CBMC) are at least as sensitive as peripheral blood mononuclear cells (PBMC) for isolation of human immunodeficiency virus type 1 from the PBMC of infected individuals. Viral replication was more efficiently monitored by a p24 antigen capture assay than by a viral reverse transcriptase test, regardless of whether CBMC or PBMC were employed. We also found that CBMC and PBMC yielded similar results with regard to the susceptibility profiles of both wild-type and drug-resistant variants of human immunodeficiency virus type 1 for 3'-azido-3'-deoxythymidine, 2',3'-dideoxycytidine, and the (-) enantiomer of 2',3'-dideoxy-3'-thiacytidine. Finally, viruses isolated on CBMC could be routinely grown on PBMC and vice versa.
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PMID:Comparison of cord blood and peripheral blood mononuclear cells as targets for viral isolation and drug sensitivity studies involving human immunodeficiency virus type 1. 752 27

Three flavans, daphnodorins A, B and C isolated from Dahpne odora THUNB. were tested for their abilities to inhibit human immunodeficiency virus type 1 (HIV-1(IIIB)) replication in MT-4 cells. The effective concentrations (EC50) of daphnodorins A, B and C against HIV-1-induced cytolysis were 0.26 +/- 0.08, 1.8 +/- 0.6 and 3.6 +/- 0.5 micrograms/ml, respectively. Also these three compounds showed inhibitory effects of p24 antigen in human peripheral blood lymphocytes. As compared with 2',3'-dideoxycytidine 5'-triphosphate (DDC-TP), daphnodorin A and daphnodorin C had relatively weak inhibitory effects on the reverse transcriptase of HIV-1, while daphnodorin B did not show any inhibitory effect at concentrations up to 1000 micrograms/ml. These three compounds showed marked inhibitory effects on syncytium formation between HIV-1(IIIB)-infected and uninfected MOLT-4 (clone 8) cells at 3-30 micrograms/ml without inducing cytotoxicity. The concentrations of the compounds blocking syncytium formation were consistent with the effective concentrations (EC50) against HIV-induced cytolysis of MT-4 cells. These results, differing from reverse transcriptase inhibitors, suggest that the daphnodorins exert their anti-HIV-1 activity through inhibition of early events of viral replication including adsorption of the virions to the cells or the subsequent entry.
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PMID:Inhibition of human immunodeficiency virus type 1 (HIV-1) replication by daphnodorins. 752 15

A concentrated live retrovirus is required for in vitro experiments. A cuprammonium-regenerated cellulose hollow fiber, termed BMM, originally developed for biohazardous viral removal, was used to concentrate two different retroviruses, an ecotropic murine leukemia virus (MuLV) and human immunodeficiency virus (HIV). The BMM was useful for concentrating live virus suspension 10- to 30-fold from 500-1000 ml of culture supernatant. The ecotropic MuLV concentrated by BMM was demonstrated to be viable and biologically intact by XC plaque-forming assay and reverse transcriptase assay. The concentrated MuLV reached a much higher titer in the spleen in mice than the original one. The virus concentration assessed by p24 antigen for HIV was clearly higher than that of the original culture supernatant of HIV-infected cell lines. Since BMM hollow fibers trapped viruses by the sieving mechanism but not by adsorption, the viral particles were recovered by washing and the total live virus recovery rate was high, about 50%. Furthermore 60 min sufficed to handle 1000 ml of supernatant in the case of a filtration area of 0.03 m2. These results show that the BMM provides us with a rapid, safe and efficient method for concentrating live retroviruses.
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PMID:Concentration of live retrovirus with a regenerated cellulose hollow fiber, BMM. 752 92

The in-vitro susceptibilities of two strains of feline immunodeficiency virus to 18 antiviral agents were determined in two cell lines. In terms of inhibiting p24 antigen production, the nucleoside-analogue reverse transcriptase inhibitors were the most effective compounds. Inhibition was also observed with aurintricarboxylic acid, phosphonoformate and butyldeoxynorjirimycin, but not with the other agents tested.
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PMID:Susceptibility in cell culture of feline immunodeficiency virus to eighteen antiviral agents. 753 45


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