Search results for "Viral envelope"
showing 10 items of 102 documents
DNA-mediated immunization to hepatitis B virus envelope proteins: preS antigen secretion enhances the humoral response.
1999
In order to design optimized DNA vectors as genetic vaccines against infections with the hepatitis B virus (HBV) we investigated if secretion or retention of the viral antigens has an influence on the quality and quantity of the humoral immune response. Intramuscular injection of plasmid DNA encoding the HBV large L envelope protein, known to be retained within host cells, induced only a weak response in mice whereas a vector expressing the secretion-competent small S envelope protein elicited strong and sustained immunity. Immunization with rearranged envelope genes further demonstrated that secretion affects the magnitude of the immune response. In situ expression of modified small and mi…
Enhanced Gene Delivery by Avidin-Displaying Baculovirus
2004
Flexible alteration of virus surface properties would be beneficial for enhanced and targeted gene delivery. A useful approach could be based on a high-affinity receptor–ligand pair, such as avidin and biotin. In this study, we have constructed an avidin-displaying baculovirus, Baavi. Avidin display was expected to enhance cell transduction due to the high positive charge of avidin in physiological pH and to provide a binding site for covering the virus with desired biotinylated ligands. Successful incorporation of avidin on the virus envelope was detected by immunoblotting and electron microscopy. Multiple biotin-binding sites per virus were detected with fluorescence-correlation spectrosc…
T-cell receptor transfer into human T cells with ecotropic retroviral vectors
2014
Adoptive T-cell transfer for cancer immunotherapy requires genetic modification of T cells with recombinant T-cell receptors (TCRs). Amphotropic retroviral vectors (RVs) used for TCR transduction for this purpose are considered safe in principle. Despite this, TCR-coding and packaging vectors could theoretically recombine to produce replication competent vectors (RCVs), and transduced T-cell preparations must be proven free of RCV. To eliminate the need for RCV testing, we transduced human T cells with ecotropic RVs so potential RCV would be non-infectious for human cells. We show that transfection of synthetic messenger RNA encoding murine cationic amino-acid transporter 1 (mCAT-1), the re…
Protein targeting to the plasma membrane of adult skeletal muscle fiber: an organized mosaic of functional domains.
2001
The plasma membrane of differentiated skeletal muscle fibers comprises the sarcolemma, the transverse (T) tubule network, and the neuromuscular and muscle-tendon junctions. We analyzed the organization of these domains in relation to defined surface markers, beta-dystroglycan, dystrophin, and caveolin-3. These markers were shown to exhibit highly organized arrays along the length of the fiber. Caveolin-3 and beta-dystroglycan/dystrophin showed distinct, but to some extent overlapping, labeling patterns and both markers left transverse tubule openings clear. This labeling pattern revealed microdomains over the entire plasma membrane with the exception of the neuromuscular and muscle-tendon j…
A Bimolecular Multicelular complementation system for the detection of syncytium formation: A new methodology for the identification of entry inhibit…
2019
AbstractFusion of viral and cellular membranes is a key step during the viral life cycle. Enveloped viruses trigger this process by means of specialized viral proteins expressed on their surface, the so called viral fusion proteins. There are multiple assays to analyze the viral entry including those that focus on the cell-cell fusion induced by some viral proteins. These methods often rely on the identification of multinucleated cells (syncytium) as a result of cell membrane fusions. In this manuscript, we describe a novel methodology for the study of cell-cell fusion. Our approach, named Bimolecular Multicelular Complementation (BiMuC), provides an adjustable platform to investigate quali…
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…
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…
ICTV Virus Taxonomy Profile: Cystoviridae
2017
The family Cystoviridae includes enveloped viruses with a tri-segmented dsRNA genome and a double-layered protein capsid. The innermost protein shell is a polymerase complex responsible for genome packaging, replication and transcription. Cystoviruses infect Gram-negative bacteria, primarily plant-pathogenic Pseudomonas syringae strains. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Cystoviridae, which is available at http://www.ictv.global/report/cystoviridae.
Presentation of an Immunodominant Immediate-Early CD8+ T Cell Epitope Resists Human Cytomegalovirus Immunoevasion.
2013
Control of human cytomegalovirus (HCMV) depends on CD8+ T cell responses that are shaped by an individual's repertoire of MHC molecules. MHC class I presentation is modulated by a set of HCMV-encoded proteins. Here we show that HCMV immunoevasins differentially impair T cell recognition of epitopes from the same viral antigen, immediate-early 1 (IE-1), that are presented by different MHC class I allotypes. In the presence of immunoevasins, HLA-A- and HLA-B-restricted T cell clones were ineffective, but HLA-C*0702-restricted T cell clones recognized and killed infected cells. Resistance of HLA-C*0702 to viral immunoevasins US2 and US11 was mediated by the alpha3 domain and C-terminal region …
Cloning and expression of the complement receptor glycoprotein C from Herpesvirus simiae (herpes B virus): protection from complement-mediated cell l…
2003
Simian herpes B virus (SHBV) is the herpes simplex virus (HSV) homologue for the species MACACA: Unlike in its natural host, and unlike other animal herpesviruses, SHBV causes high mortality in accidentally infected humans. SHBV-infected cells, like those infected with HSV-1 and equine herpesvirus types 1 and 4, express complement C3 receptor activity. To study immunoregulatory functions involved in susceptibility/resistance against interspecies transmission, the SHBV glycoprotein C (gC(SHBV)) gene (encoding 467 aa) was isolated. Sequence analysis revealed amino acid identity with gC proteins from HSV-2 (46.9 %), HSV-1 (44.5 %) and pseudorabies virus (21.2 %). Highly conserved cysteine resi…