Search results for "Virology"

Protection of HeLa‐T4 + cells against human immunodeficiency virus (HIV) infection after stable transfection with HIV LTR‐2‘,5‘‐oligoadenylate synthe…

1990

An expression vector (pU3R-III/2-5AS) of human 2',5'-oligoadenylate (2-5A) synthetase was constructed in which a cDNA encoding an active form of the enzyme was located 3' to a 3'-long terminal repeat (LTR) of human immunodeficiency virus type 1 (HIV-1). The LTR-directed expression of this hybrid DNA could be activated in trans by the HIV tat gene product. This vector was used for transfection of HeLa-T4+ cells, which are permissive to HIV infection, as well as of normal HeLa cells. HIV replication after infection of the CD4-receptor-bearing HeLa-T4+ cells with HIV-1 was found to be strongly reduced when drug-selected cells cotransfected with pU3R-III/2-5AS and a hygromycin B resistance gene…

Spread of hepatitis B virus infection among family contacts of asymptomatic HBsAg carriers

1979

Family members of 34 asymptomatic HBsAg carriers were tested for different hepatitis B virus (HBV) markers. Among 67 family members tested 24 (36%) presented signs of a past or ongoing HBV-infection. Spread of HBV-infection was particularly high in those families in which the HBsAg carrier was positive for HBeAg and Dane particle-associated DNA polymerase activity. Non-parenteral “horizontal” transmission of HBV among spouses and brothers and sisters and probably parenteral vertical transmission of HBV from carrier mothers to their infants occurred in approximately the same frequency. Fathers transmitted HBV unfrequently to their offsprings. The results show that the risk to acquire a HBV-i…

Trapping the Enemy: Vermamoeba vermiformis Circumvents Faustovirus Mariensis Dissemination by Enclosing Viral Progeny inside Cysts

2019

Viruses depend on cells to replicate and can cause considerable damage to their hosts. However, hosts have developed a plethora of antiviral mechanisms to counterattack or prevent viral replication and to maintain homeostasis. Advantageous features are constantly being selected, affecting host-virus interactions and constituting a harsh race for supremacy in nature. Here, we describe a new antiviral mechanism unveiled by the interaction between a giant virus and its amoebal host. Faustovirus mariensis infects Vermamoeba vermiformis, a free-living amoeba, and induces cell lysis to disseminate into the environment. Once infected, the cells release a soluble factor that triggers the encystment…

Rapid development of Epstein-Barr virus-associated Hodgkin's disease after cessation of foscarnet therapy in an HIV-infected patient.

2000

Epidemiological features suggest a link between Hodgkin's disease (HD) and Epstein-Barr virus (EBV) infection1. Indeed, EBV genome and expression of latent antigens can be found in Reed-Sternberg cells. In the majority of cases HD in HIV patients seems to be EBV-associated. We report on a 51-year-old HIV-infected patient in whom EBV-positive HD of mixed cellularity rapidly developed within one month after cessation of treatment with intravenous foscarnet.

Crystallization After Intravitreous Foscarnet Injections

2012

The nuclear protein Sge1 of Fusarium oxysporum is required for parasitic growth

2009

Dimorphism or morphogenic conversion is exploited by several pathogenic fungi and is required for tissue invasion and/or survival in the host. We have identified a homolog of a master regulator of this morphological switch in the plant pathogenic fungus Fusarium oxysporum f. sp. lycopersici. This non-dimorphic fungus causes vascular wilt disease in tomato by penetrating the plant roots and colonizing the vascular tissue. Gene knock-out and complementation studies established that the gene for this putative regulator, SGE1 (SIX Gene Expression 1), is essential for pathogenicity. In addition, microscopic analysis using fluorescent proteins revealed that Sge1 is localized in the nucleus, is no…

Benchmark of thirteen bioinformatic pipelines for metagenomic virus diagnostics using datasets from clinical samples

2021

AbstractMetagenomic sequencing is increasingly being used in clinical settings for difficult to diagnose cases. The performance of viral metagenomic protocols relies to a large extent on the bioinformatic analysis. In this study, the European Society for Clinical Virology (ESCV) Network on NGS (ENNGS) initiated a benchmark of metagenomic pipelines currently used in clinical virological laboratories.MethodsMetagenomic datasets from 13 clinical samples from patients with encephalitis or viral respiratory infections characterized by PCR were selected. The datasets were analysed with 13 different pipelines currently used in virological diagnostic laboratories of participating ENNGS members. The…

The discovery, distribution, and diversity of DNA viruses associated with Drosophila melanogaster in Europe

2021

Drosophila melanogaster is an important model for antiviral immunity in arthropods, but very few DNA viruses have been described from the family Drosophilidae. This deficiency limits our opportunity to use natural host-pathogen combinations in experimental studies, and may bias our understanding of the Drosophila virome. Here, we report fourteen DNA viruses detected in a metagenomic analysis of 6668 pool-sequenced Drosophila, sampled from forty-seven European locations between 2014 and 2016. These include three new nudiviruses, a new and divergent entomopoxvirus, a virus related to Leptopilina boulardi filamentous virus, and a virus related to Musca domestica salivary gland hypertrophy viru…

Kinetics of cytomegalovirus (CMV) pp65 and IE-1-specific IFNgamma CD8+ and CD4+ T cells during episodes of viral DNAemia in allogeneic stem cell tran…

2010

The dynamics of CMV pp65 and IE-1-specific IFNgamma-producing CD8(+) (IFNgamma CD8(+)) and CD4(+) (IFNgamma CD4(+)) T cells and CMV DNAemia were assessed in 19 pre-emptively treated episodes of active CMV infection. Peripheral counts of IFNgamma CD8(+) and IFNgamma CD4(+) T cells inversely correlated with CMV DNAemia levels (P = <0.001 and P = 0.003, respectively). A threshold value of 1.3 cells/microl predicting CMV DNAemia clearance was established for IFNgamma CD8(+) T cells (PPV, 100%; NPV, 93%) and for IFNgamma CD4(+) T cells (PPV, 100%; NPV, 75%). Undetectable T-cell responses were usually observed at the time of initiation of pre-emptive therapy. Either a rapid (within 7 days) or a d…

Immunological insights into the pathogenesis of active CMV infection in non-immunosuppressed critically ill patients.

2011

Dissociation of cytomegalovirus (CMV) DNA loads between the lower respiratory tract and blood, with high levels in the former compartment and low or undetectable levels in the latter, commonly occurs during active CMV infection in critically ill patients despite the presence of high frequencies of CMV-specific IFN-γ-producing CD8+ and CD4+ T cells in blood. Data presented in this case report suggest that inter-compartmental differences in interleukin-10 (IL-10) levels may, in part, explain the pathobiology of this phenomenon. In the absence of ganciclovir treatment, a significant correlation was observed between IL-10 levels and CMV DNA loads in lower respiratory tract specimens (P = 0.016)…