Search results for "Virology"
showing 10 items of 2354 documents
Differentiation of herpes simplex virus-induced fusion from without and fusion from within by cyclosporin A and compound 48/80.
1991
Treating strains of herpes simplex virus (HSV) in culture with either cyclosporin A or compound 48/80, allowed the strains to be divided into two groups. Group 1 contains the strains ANG and HFEM of HSV-1 and Lux syn (HSV-2) producing fusion from within (FFWI) and fusion from without (FFWO). Cyclosporin A fails to inhibit both types of fusion at concentrations up to 100 microM. Strains ANG and HFEM belong to the syn 3 marker locus group identified for HSV-1. Group 2 contains all other fusion-producing strains of HSV tested so far. Cyclosporin A inhibits FFWI at concentrations as low as 10 to 20 microM. These strains belong to the syn locus marker groups 1, 2, 4 and 5. From the fact that mut…
Role of lipid rafts in virus infection
2009
Rafts are domains of the plasma membrane, enriched in cholesterol and sphingolipids; they form a platform for signaling proteins and receptors. The lipid rafts are utilized in the replication cycle of numerous viruses. Internalization receptors of many viruses localize to rafts or are recruited there after virus binding. Arrays of signal transduction proteins found in rafts contribute to efficient trafficking and productive infection. Some viruses are dependent on raft domains for the biogenesis of their membranous replication structures. Finally, rafts are often important in virus assembly and budding. Subsequently, raft components in the viral envelope may be vital for the entry to a new…
Evolution of RNA virus in spatially structured heterogeneous environments
2003
A hallmark of the infectious cycle for many RNA viruses parasitizing multicellular hosts is the need to invade and successfully replicate in tissues that comprise a variety of cell types. Thus, multicellular hosts represent a heterogeneous environment to evolving viral populations. To understand viral adaptation to multicellular hosts, we took a double approach. First, we developed a mathematical model that served to make predictions concerning the dynamics of viral populations evolving in heterogeneous environments. Second, the predictions were tested by evolving vesicular stomatitis virus in vitro on a spatially structured environment formed by three different cell types. In the absence o…
Two mutations in gB-1 and gD-1 of herpes simplex virus type 1 are involved in the "fusion from without" phenotype in different cell types.
1996
Previous studies have shown that certain strains of herpes simplex viruses type 1 (HSV-1) are able to induce “fusion from without” (FFWO) which means no transcription or translation of the viral genome happens. The main determinants for FFWO in BHK cells are mutations in the C-terminal part of gB-1. But single mutations in this part of the genome are not sufficient to transfer the FFWO phenotype also to Vero cells. Here, we report that FFWO of HSV strains indeed need additional mutations in the N-terminal part of gD in order to produce the FFWO phenotype in BHK and Vero cells. By marker transfer we are able to show that loss of mutations in the N-terminal part of gD influences the ability t…
Collective Viral Spread Mediated by Virion Aggregates Promotes the Evolution of Defective Interfering Particles
2020
Recent insights have revealed that viruses use a highly diverse set of strategies to release multiple viral genomes into the same target cells, allowing the emergence of beneficial, but also detrimental, interactions among viruses inside infected cells. This has prompted interest among microbial ecologists and evolutionary biologists in studying how collective dispersal impacts the outcome of viral infections. Here, we have used vesicular stomatitis virus as a model system to study the evolutionary implications of collective dissemination mediated by viral aggregates, since this virus can spontaneously aggregate in the presence of saliva. We find that saliva-driven aggregation has a dual ef…
Cellular interactions ofCandida albicanswith human oral epithelial cells and enterocytes
2010
The human pathogenic fungus Candida albicans can cause systemic infections by invading epithelial barriers to gain access to the bloodstream. One of the main reservoirs of C. albicans is the gastrointestinal tract and systemic infections predominantly originate from this niche. In this study, we used scanning electron and fluorescence microscopy, adhesion, invasion and damage assays, fungal mutants and a set of fungal and host cell inhibitors to investigate the interactions of C. albicans with oral epithelial cells and enterocytes. Our data demonstrate that adhesion, invasion and damage by C. albicans depend not only on fungal morphology and activity, but also on the epithelial cell type an…
Recombinant virus-like particles of a norovirus (genogroup II strain) administered intranasally and orally with mucosal adjuvants LT and LT(R192G) in…
2003
We investigated the immune response induced by mucosal immunization of BALB/c mice with virus-like particles (VLPs) of a genogroup II norovirus, Dijon171/96 virus, produced in the baculovirus system. VLPs administered alone by the intranasal route induced a high serum antibody response as well as fecal IgA, which were enhanced when the heat-labile Escherichia coli toxin or its non toxic mutant LT(R192G) was coadministered. In these conditions, the oral route was also efficient. Cytokine production by cells from different lymphoid tissues was then assessed after in vitro restimulation. A Th1/Th2-like response was observed in cervical lymph node and Peyer's patch (PP) cell cultures from mice …
Reversibility of Central Nervous System Adverse Events in Course of Art
2022
The purpose of this study is to evaluate the frequency of central nervous system adverse events (CNS-AE) on dolutegravir (DTG) and non-DTG containing ART, and their reversibility, in the observational prospective SCOLTA cohort. Factors associated with CNS-AE were estimated using a Cox proportional-hazards model. 4939 people living with HIV (PLWH) were enrolled in DTG (n = 1179) and non-DTG (n = 3760) cohorts. Sixty-six SNC-AE leading to ART discontinuation were reported, 39/1179 (3.3%) in DTG and 27/3760 (0.7%) in non-DTG cohort. PLWH naïve to ART, with higher CD4 + T count and with psychiatric disorders were more likely to develop a CNS-AE. The risk was lower in non-DTG than DTG-cohort (aH…
T helper cell- and CD40-dependent germline IgM prevents chronic virus-induced demyelinating disease
2012
Generation of antiviral IgM is usually considered as a marker of a short-lived initial antibody response that is replaced by hypermutated and more-efficient IgG. However, once viruses have established a particular niche for their persistence (e.g., within the CNS), the immune system has to specifically mobilize a broad range of antimicrobial effectors to contain the pathogen in the long term. Infection of the CNS with the mouse hepatitis virus (MHV) provides a unique model situation in which the extent of inflammatory CNS disease is determined by the balance between antiviral immune control, viral replication, and immune-mediated damage. We show here that whereas antibody- or B cell-defici…
Cortical astrocytosis in juvenile rhesus monkeys infected with simian immunodeficiency virus
1993
The pattern of expression of GFAP immunoreactivity in astrocytes of the juvenile rhesus monkey cortex was examined following infection with simian immunodeficiency virus (SIV). Blocks of cerebral cortex plus subjacent white matter from saline- and formalin-perfused brain were examined by peroxidase-linked immunochemical and immunofluorescence staining of deparaffinized sections. Strong GFAP immunoreactivity was found in astrocytic cells in both uninfected and SIV-infected juvenile macaque in the subpial cerebral cortex and in subcortical white matter, where GFAP-positive cells were abundant. GFAP staining of cortical layers 2-6 on the other hand was weak or absent in three uninfected contro…