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)

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

The hepatitis B virus is a member of an unusual family of noncytopathogenic, hepatotropic DNA viruses--the hepadnaviruses. The complete virus comprises a lipoprotein coat, the hepatitis B surface antigen, enveloping a nucleocapsid core that contains a small, circular DNA molecule. Four open reading frames have been identified on the hepatitis B virus DNA genome. They encode seven proteins, including a hepatitis B virus DNA polymerase molecule with reverse transcriptase activity. The replication of the virus resembles that of retroviruses and occurs predominantly but not exclusively in hepatocytes. Virus variants involving genomic mutations have been identified. Testing for hepatitis B surface antigen permits detection of many but not all acutely infected patients. Diagnosis of acute infection rests on the identification of IgM antibodies to the hepatitis B core antigen. Antibody to hepatitis B surface antigen appears in serum during the convalescent phase of hepatitis B virus infection. It is the neutralizing, protective antibody largely responsible for immunity to reinfection. In persistent infection hepatitis B surface antigen is present, antibody to hepatitis B core antigen is predominantly an IgG antibody, antibody to hepatitis B surface antigen is not detectable or is present in very low titers and viral replication may be active. Persistent infection leads to an asymptomatic carrier state, chronic hepatitis, cirrhosis and hepatocellular carcinoma. No specific treatment exists for acute hepatitis B virus infection. Current data indicate that approximately 50% of adults who have chronic infection achieve virologic, biochemical and histologic remission from treatment with alpha-2b-interferon.
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PMID:Hepatitis B today: clinical and diagnostic overview. 832 12

The effects of long-term infection with Helicobacter pylori on the gastric mucosa of Mongolian gerbils were examined. Colonization by H. pylori was evaluated by both microaerobic cultivation and real-time reverse transcriptase PCR (RT-PCR). Persistent infection with H. pylori in gastric mucosa was detected by real-time RT-PCR during 6 months after infection, but no H. pylori was isolated 4 months after infection by cultivation. Infiltration with neutrophils and mononuclear cells was observed from 2 months after infection. Both intestinal metaplasia and gastric atrophy were also detected from 2 months after infection. The results by enzyme-linked immunosorbent assay indicated that antibody titers against whole H. pylori antigens, H. pylori heat shock protein 60 (HSP60), and Escherichia coli GroEL were significantly higher in the infected gerbils than in noninfected gerbils. After long-term infection with H. pylori for 18 months, marked atrophy of gastric mucosa and multiple cysts in the submucosa were observed in the glandular stomach of the infected gerbils. In addition, squamous cell papilloma with hyperkeratosis was observed in cardia of all the infected gerbils. These results indicate that evaluation of bacterial colonization during long-term infection can be done by real-time RT-PCR and that mucosal damage might be induced by host immune response against whole H. pylori antigen.
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PMID:Long-term infection of Mongolian gerbils with Helicobacter pylori: microbiological, histopathological, and serological analyses. 1569 32

The mechanisms of viral persistence of infectious pancreatic necrosis virus (IPNV) are not well understood. In this study we have used a model of IPNV persistently infected CHSE (Chinook salmon embryonic) cells as correlate of persistent infection in fish focusing on differentially expressed genes using subtractive hybridization (SSH). Selected genes were also analyzed by quantitative real-time PCR (qPCR) in persistently infected parr of Atlantic salmon. Persistent infection was established by growing CHSE cells surviving an IPNV infection. Infection in rescued cells was non-lytic with a virus yield of 10(3)-10(5) TCID(50)/ml of supernatant, resembling what can be found during a persistent infection in vivo. By comparing gene expression in persistently infected cell vs. non-infected cells we found an upregulation of genes involved in direct interaction or degradation of viral proteins, proteasome activating subunit 3, and of ATRX (X-linked alpha-thalassemia/mental retardation syndrome), a transcription repressor, which may indicate a repression of viral replication through reduced transcription. Further ephrin B1 (signal-transduction group) was found strongly up-regulated, and receptors for various ephrins are used for cell interaction and as entry points for other viruses in higher vertebrates. Endonuclease/reverse transcriptase 1 (RVT1) was also found highly up-regulated in persistently infected cells. The comparison of persistently infected cells to in vivo infected fish showed that the expression profiles found in CHSE cells give corresponding results for selected genes, as ATRX, ephrin B1 and RVT-1. We observed similar results by use of two independent methods (SSH and qPCR) for 8 out of 15 genes analyzed and the transcript profile of persistently IPNV-infected cells involve upregulation of genes encoding proteins involved in viral protein degradation and translation inhibition. The understanding is that this may contribute to keep the number of virus particles low during viral persistence.
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PMID:Differentially expressed genes following persistent infection with infectious pancreatic necrosis virus in vitro and in vivo. 2015 4