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)

Equine infectious anemia virus (EIAV) has a density of 1.154 g/cm3 in sucrose a high-molecular-weight RNA similar in size to Rauscher murine leukemia virus, and an internal virion reverse transcriptase that utilizes the synthetic RNA template poly(rA) but not the synthetic DNA template poly(dA), both with (dT)12 as primer. Although capable of utilizing manganese at low concentrations (approximately 0.1 mM), EIAV reverse transcriptase showed highest activity in the presence of 9 mM magnesium. The major protein of EIAV has a slightly lower molecular weight than the comparable protein of type C viruses and co-electrophoresed with 125I-labeled p25 of Mason-Pfizer monkey virus. A reference horse serum with antibodies to the major EIAV protein reacted only with EIAV and not with other type C or non-type C retraviruses. Reciprocally, a broadly reactive serum to type C virus p30s and specific sera to a variety of non-type C retraviruses did not react with EIAV. We recommend the inclusion of EIAV in the family Retraviridae.
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PMID:Equine infectious anemia virus: evidence favoring classification as a retravirus. 6 Dec 83

The polymerase chain reaction (PCR) was used to amplify, clone, and express eight DNA fragments encoding p25, p16, reverse transcriptase (RT) core, C'-terminal RT, N'- and C'-terminals of external (gp70), and transmembrane (gp40) envelope proteins from visna virus infectious recombinant DNA. Efforts were focused on characterizing the nature of the humoral immune response of ovine progressive pneumonia (OPP) virus infected animals and identifying the conserved and prime-reactive antigenic determinants that have potential diagnostic value. This communication reports that the N'-terminal region of gp40 appeared to be the most immunoreactive of the bacterially expressed proteins and could serve as a sensitive immunodiagnostic antigen for the detection of OPP infection.
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PMID:Analysis of antibody response to ovine lentivirus by using viral gene products expressed in a prokaryotic system. 138 77

A two-site enzyme linked immunosorbent assay (ELISA) was developed to detect and quantify the HIV1 core protein p25 in the cell-free supernatant from virus-infected CEM cell culture, and compared with other assays. The assay, based on a sandwich method, employs two monoclonal antibodies (mAb) directed against different epitopes on the p25 core protein of HIV1, one used for p25 antigen capture and the other as a biotinylated probe. This immunoassay is sensitive enough to detect as little as 30 pg/ml of recombinant p25, the range of sensitivity of commercial kits, and therefore compares favourably with the conventional reverse transcriptase assay. Moreover, several hundred assays can be monitored quite conveniently by this simple ELISA procedure, which represents a useful tool for detection of HIV1 replication in microculture systems and rapid screening of antiretroviral agents using the reference strain HIV1-BRU as a model system.
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PMID:Use of monoclonal antibodies for the detection and quantitation of HIV1 core protein p25: comparative evaluation of in vitro HIV1 infection by immunofluorescence, antigen capture ELISA and reverse transcriptase assays. 170 58

Nasal exudate and tumour tissue from goats with enzootic nasal tumours were shown to contain a reverse transcriptase activity associated with a particle of buoyant density typical of retroviruses. The same particle contained a 25,000 Mr protein that cross-reacted with the p27 of Mason-Pfizer monkey virus (MPMV) and with p25 of sheep pulmonary adenomatosis retrovirus. It also contained a low Mr protein related to p10-12 of MPMV.
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PMID:Enzootic nasal tumour of goats: demonstration of a type D-related retrovirus in nasal fluids and tumours. 171 43

To study the local immune response to human immunodeficiency virus type 1 (HIV-1) in women infected by or exposed to HIV-1, 75 women were studied: 15 were IgG-seropositive but clinically asymptomatic, 15 had acquired immune deficiency syndrome (AIDS), 15 were IgG-seronegative with seropositive husbands, and 30 were healthy seronegative women who were selected as controls. Serum samples and vaginal secretions were tested for antibodies to HIV-1 IgG and IgA by Western blot analysis. Antibodies of the IgG and IgA classes were detected in serum samples and vaginal secretions from healthy seropositive women and from women with AIDS. Local IgG antibodies to all viral proteins were detected by Western blot tests. Genital IgA antibodies were mainly directed to the core proteins p18 and p25, the p68 reverse transcriptase, and the gp160 and gp41 glycoproteins; IgA antibodies to the glycoprotein gp120 were rarely recovered. Antibodies of both the IgG and IgA classes in genital secretions were directed to all viral proteins, including surface glycoproteins, and could play a role in limiting the virus infectivity on normal mucosa.
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PMID:Antibodies to human immunodeficiency virus in vaginal secretions of heterosexual women. 276 Apr 96

A murine monoclonal antibody (MAb), named C.V.K., was produced after immunization with highly purified and sonicated lymphadenopathy-associated virus (LAV). No monoclonal antibody was observed with intact virus used as immunogen. C.V.K. MAb recognizes an epitope present on the precursor gag protein of 55 kilodaltons. Western blot analysis and pulse-chase experiments support the interpretation that after p55 cleavage into p25, p18, and p13, only p18 expresses this epitope. C.V.K. MAb selectively stained only LAV-infected lymphocytes. This intracytoplasmic staining appears 3 days after the infection and is correlated with reverse transcriptase activity. Neither membrane immunofluorescence of infected lymphocytes nor neutralizing activity was observed with C.V.K. MAb. These facts suggest that p55 and p18 are not expressed at the cell membrane or on the viral envelope. C.V.K. MAb should prove useful not only in the purification of core proteins but also for detecting infected cells producing the virus in suspension or on histologic sections.
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PMID:A monoclonal antibody against LAV gag precursor: use for viral protein analysis and antigenic expression in infected cells. 300 97

A retrovirus belonging to the family of recently discovered human T-cell leukemia viruses (HTLV), but clearly distinct from each previous isolate, has been isolated from a Caucasian patient with signs and symptoms that often precede the acquired immune deficiency syndrome (AIDS). This virus is a typical type-C RNA tumor virus, buds from the cell membrane, prefers magnesium for reverse transcriptase activity, and has an internal antigen (p25) similar to HTLV p24. Antibodies from serum of this patient react with proteins from viruses of the HTLV-I subgroup, but type-specific antisera to HTLV-I do not precipitate proteins of the new isolate. The virus from this patient has been transmitted into cord blood lymphocytes, and the virus produced by these cells is similar to the original isolate. From these studies it is concluded that this virus as well as the previous HTLV isolates belong to a general family of T-lymphotropic retroviruses that are horizontally transmitted in humans and may be involved in several pathological syndromes, including AIDS.
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PMID:Isolation of a T-lymphotropic retrovirus from a patient at risk for acquired immune deficiency syndrome (AIDS). 618 83

Ovine IFN-tau is a newly described protein related to IFN-alpha that is responsible for maternal recognition of pregnancy in sheep. It has been shown to exhibit potent antiviral and antiproliferative activity. To determine its antiviral activity against feline immunodeficiency virus (FIV) and HIV, the activity of the RNA-dependent DNA polymerase, reverse transcriptase, was assayed in FIV- and HIV-infected feline and human PBL treated with IFN-tau. Significant dose-dependent inhibition of reverse transcriptase activity by IFN-tau was detected by day 6 of culture and was maintained through the peak of virus replication. In addition, production of the FIV core protein, p25, was blocked by IFN-tau. Both the amino- and carboxyl-terminal regions of IFN-tau, as identified by synthetic peptides, appear to be involved in its antiretroviral activity. Comparison of the anti-HIV activities of IFN-tau and recombinant human IFN-alpha2 (rHuIFN-alpha2) indicated that while rHuIFN-alpha2 was toxic to cells at 10,000 U/ml, IFN-tau antiretroviral activity was not associated with a decrease in either cell viability or immunologic reactivity. Thus, IFN-tau displayed potent anti-FIV and anti-HIV activity without the cytotoxicity associated with high concentrations of rHuIFN-alpha2.
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PMID:Potent anti-feline immunodeficiency virus and anti-human immunodeficiency virus effect of IFN-tau. 912 98

RAK antigens p120, p42, and p25 exhibit molecular and immunological similarity to the proteins encoded by human immunodeficiency virus type 1 (HIV-1) and are expressed by 95% of breast and gynecological cancer cases in women and prostate cancer cases in men. The binding of an epitope-specific anti-HIV-1 gp120 monoclonal antibody (MAb) (amino acids 308 to 322) to cancer RAK antigens has been found to be inhibited by a peptide derived from variable loop V3 of HIV-1. Breast cancer DNAs of 40 patients were PCR amplified with HIV-1 gp41-derived primers, and all of the samples were found to be positive. The DNA fragments amplified in seven blindly selected breast cancer samples were sequenced. The breast cancer DNA sequences showed at least 90% homology to the HIV-1 gene for gp41. Antisense oligonucleotides complementary to the HIV-1-like sequences inhibited reverse transcriptase activity and inhibited the growth of breast cancer cells in vitro. Viral particles detected in breast cancer cell lines were strongly immunogold labeled with the anti-HIV-1 gp120 MAb. The results obtained strongly suggest that the long-postulated breast cancer virus may, in fact, be related to HIV-1.
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PMID:Human immunodeficiency virus type 1-like DNA sequences and immunoreactive viral particles with unique association with breast cancer. 972 31

In small ruminant lentivirus infections, cellular immune responses are diminished in clinically affected animals. The underlying mechanisms for this are unknown. In this study, we tested the hypothesis that alterations in expression of the co-stimulatory molecules B7-1 and B7-2 are involved in infections with Visna/Maedi virus (VMV), the prototype lentivirus of sheep. We studied B7 expression levels ex vivo in peripheral blood mononuclear cells (PBMCs), determining B7 RNA levels by real time reverse transcriptase polymerase chain reaction in asymptomatic as well as clinically affected VMV-seropositive sheep. The levels of both B7 molecules were increased in VMV-seropositive asymptomatic sheep. However, in VMV clinically affected sheep, the level of CD80 (but not CD86) was low compared with the level in uninfected sheep (p < 0.05). CD80 and CD86 RNA levels were associated with the ability of PBMCs to respond to VMV gag antigens (p14, p17, and p25) by proliferation, with most seropositive asymptomatic sheep showing positive proliferative responses but clinically affected sheep showing no response. The response to p25 in clinically affected animals was increased by the addition of interleukin-2 to the cultures. Decreased recall responses to unrelated antigens (assessed by production of interferon-gamma) were also found in clinically affected sheep. Thus, among seropositive sheep, decreased B7-1 (CD80) RNA levels and diminished antigen-specific cellular immune responses in PBMCs point to a VMV disease status, whereas increased CD80 and CD86 levels and augmented cellular responses are linked to asymptomatic infection.
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PMID:Association of CD80 and CD86 expression levels with disease status of Visna/Maedi virus infected sheep. 1815 34


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