Search results for "Retrovirus"

A putative antiviral role of plant cytidine deaminases

2014

[Background]: A mechanism of innate antiviral immunity operating against viruses infecting mammalian cells has been described during the last decade. Host cytidine deaminases (e.g., APOBEC3 proteins) edit viral genomes, giving rise to hypermutated nonfunctional viruses; consequently, viral fitness is reduced through lethal mutagenesis. By contrast, sub-lethal hypermutagenesis may contribute to virus evolvability by increasing population diversity. To prevent genome editing, some viruses have evolved proteins that mediate APOBEC3 degradation. The model plant Arabidopsis thaliana genome encodes nine cytidine deaminases ( AtCDAs), raising the question of whether deamination is an antiviral mec…

Reverse-transcribing viruses (Belpaoviridae, Metaviridae, and Pseudoviridae)

2021

Fourth Edition.

Performance of QuantiFERON-TB Gold Plus for detection of latent tuberculosis infection in pregnant women living in a tuberculosis- and HIV-endemic se…

2017

We evaluated the performance of QuantiFERON-TB Gold Plus (QFT-Plus), which includes two Mycobacterium tuberculosis antigen formulations (TB1 and TB2), for detection of latent tuberculosis infection during pregnancy. Eight-hundred-twenty-nine Ethiopian pregnant women (5.9% HIV-positive) were tested with QFT-Plus, with bacteriological sputum analysis performed for women with clinically suspected tuberculosis and HIV-positive women irrespective of clinical presentation. QFT-Plus read-out was categorized according to the conventional cut-off (0.35 IU/ml) for both antigen formulations. In addition, we analysed the distribution of QFT-Plus results within a borderline zone (0.20–0.70 IU/ml), and i…

Inhibition of human T-cell leukemia virus type I replication in primary human T cells that express antisense RNA

1989

The human T-cell leukemia virus type I is associated with adult T-cell leukemia-lymphoma in humans, a disease which is induced by a malignant transformation of T lymphocytes. Retrovirus vectors carrying human T-cell leukemia virus type I-derived sequences in reversed transcriptional orientation were used to express antisense RNA transcripts in primary human leukocytes. Human T-cell leukemia virus type I replication and virus-mediated immortalization were inhibited in cells harboring antisense constructs. This study suggests that retrovirus-mediated antisense RNA inhibition can be used to protect primary human T-lymphocytes from human T-cell leukemia virus type I-mediated cell transformation.

Strong immunogenic potential of a B7 retroviral expression vector: generation of HLA-B7-restricted CTL response against selectable marker genes.

1998

The stimulation of a specific immune response is an attractive goal in cancer therapy. Gene transfer of co-stimulatory molecules and/or cytokine genes into tumor cells and the injection of these genetically modified cells leads to tumor rejection by syngeneic hosts and the induction of tumor immunity. However, the development of host immune response could be either due to the introduced immunomodulatory genes or due to vector components. In this study, human renal cell carcinoma cell lines were modified by a retrovirus to express the co-stimulatory molecule B7-1 together with the hygromycin/thymidine kinase fusion protein (HygTk) as positive and negative selection markers. These B7-1-transd…

Immune characterization of the HBHA-specific response in Mycobacterium tuberculosis-infected patients with or without HIV infection.

2017

Introduction RD1-based Interferon-γ Release Assays (IGRAs) cannot distinguish latent from active tuberculosis (TB) disease. Conversely, a positive response to heparin-binding haemagglutinin (HBHA)-based IGRAs, among TB-infected subjects, correlates with Mycobacterium tuberculosis (Mtb) containment and low risk of TB progression. The aim of this study was to characterize HBHA-immune responses in HIV-infected and uninfected subjects with active TB or latent TB infection (LTBI). Methods 49 subjects were prospectively enrolled: 22 HIV-uninfected (13 TB, 9 LTBI) and 27 HIV-infected (12 HIV-TB, 15 HIV-LTBI). Whole blood and peripheral blood mononuclear cells were stimulated with HBHA and RD1 anti…

2015

Bracoviruses are symbiotic viruses associated with tens of thousands of species of parasitic wasps that develop within the body of lepidopteran hosts and that collectively parasitize caterpillars of virtually every lepidopteran species. Viral particles are produced in the wasp ovaries and injected into host larvae with the wasp eggs. Once in the host body, the viral DNA circles enclosed in the particles integrate into lepidopteran host cell DNA. Here we show that bracovirus DNA sequences have been inserted repeatedly into lepidopteran genomes, indicating this viral DNA can also enter germline cells. The original mode of Horizontal Gene Transfer (HGT) unveiled here is based on the integrativ…

Placental endogenous retrovirus (ERV): structural, functional, and evolutionary significance

1998

Summary That endogenous retrovirus (ERV) is present within the placenta of humans and other mammals has been known for the past 25 years, but the significance of this observation is still not fully understood. Much molecular biological data have emerged in recent years to support the earlier electron microscopic data on the presence of placental ERV. The evidence for ERV in animal and human placental tissue is presented, then integrated with data on the the presence of ERV in a range of other tissues, in particular teratocarcinoma cells. Placental invasiveness and maternal immunosuppression are then discussed in relation to metalloproteinase secretion, the immunosuppressive potential of ret…

Evolution of gypsy Endogenous Retrovirus in the Drosophila obscura Species Group

2000

The Ty3/gypsy family of retroelements is closely related to retroviruses, and some of their members have an open reading frame resembling the retroviral gene env. Sequences homologous to the gypsy element from Drosophila melanogaster are widely distributed among Drosophila species. In this work, we report a phylogenetic study based mainly on the analysis of the 5' region of the env gene from several species of the obscura group, and also from sequences already reported of D. melanogaster, Drosophila virilis, and Drosophila hydei. Our results indicate that the gypsy elements from species of the obscura group constitute a monophyletic group which has strongly diverged from the prototypic D. m…

Sleeping Beauty transposon system – future trend in T-cell-based gene therapies?

2006

Evaluation of: Huang X, Wilber AC, Bao L et al.: Stable gene transfer and expression in human primary T cells by the Sleeping Beauty transposon system. Blood 107, 483–491 (2006). The Sleeping Beauty (SB) transposon system can mediate stable gene transfer and expression in primary human T cells. Optimal in vitro conditions for maximum gene transfer efficiencies have been developed with regard to further application of the SB transposon system in T cell based gene therapies. This raises the question of whether or not the SB transposon system is a convincing alternative for virus-mediated gene transfer based on the currently available data. Here, we will discuss controversial safety and effic…