Viral Envelope (viral + envelope)

Distribution by Scientific Domains


Selected Abstracts


A self-adjuvanting multiepitope immunogen that induces a broadly cross-reactive antibody to hepatitis C virus,

HEPATOLOGY, Issue 4 2007
Joseph Torresi
We describe a peptide-based strategy for HCV vaccine design that addresses the problem of variability in hypervariable region 1 (HVR1). Peptides representing antibody epitopes of HVR1 from genotype 1a were synthesized and incorporated into multideterminant immunogens that also included lipid moieties and helper T (Th) cell epitopes. Mice inoculated with these polyepitopes generated strong antibody responses. Antibody titers were highest in mice inoculated with polyepitope immunogens which contained the lipid moiety dipalmitoyl- S -glyceryl cysteine (Pam2Cys). Antisera were tested for their potential to neutralize HCV by 3 currently available assays. Antibodies elicited in mice by the polyepitope-based vaccine candidates were able to (1) bind to E2 expressed on the surface of E1/E2-transfected human embryonic kidney (HEK) 293T cells, (2) capture HCV of different genotypes (1, 2, and 3) from the serum of chronically infected humans in an immune capture RT-PCR assay and (3) inhibit HCVpp entry into Huh7 cells. Antibody present in the sera of patients chronically infected with HCV genotypes 1, 2, 3, and 4 also bound to the HVR1-based polyepitope. Conclusion: These results demonstrate the potential of self-adjuvanting epitope-based constructs in the development and delivery of cross-reactive immunogens that incorporate potential neutralizing epitopes present within the viral envelope of HCV. (HEPATOLOGY 2007;45:911,920.) [source]


Restricted transgene persistence after lentiviral vector-mediated fetal gene transfer in the pregnant rabbit model

THE JOURNAL OF GENE MEDICINE, Issue 9 2008
Rafael Moreno
Abstract Background Prenatal gene transfer may enable early causal intervention for the treatment or prevention of many devastating diseases. Nevertheless, permanent correction of most inherited disorders requires a sustained level of expression from the therapeutic transgene, which could theoretically be achieved with integrating vectors. Methods Rabbit fetuses received 8.5 × 106 HIV-based recombinant lentivirus particles containing the enhanced green fluorescent protein (EGFP) transgene by intrahepatic, intra-amniotic or intraperitoneal injection at 22 days of gestation. Provirus presence and transgene expression in rabbit tissues were evaluated at both 1.5 and 16 weeks post- in utero intervention by polymerase chain reaction (PCR) and reverse transcriptase-PCR, respectively. Moreover, we assessed persistence of EGFP by immunohistochemistry. Enzyme-linked immunosorbent assays confirmed the development of antibodies specific against both the viral vector and the reporter protein. Results Regardless of the route of administration employed, lentiviral vector-based in utero gene transfer was safe and reached 85% of the intervened fetuses at birth. However, the integrated provirus frequency was significantly reduced to 50% of that in young rabbits at 16 weeks post-treatment. In these animals, EGFP expression was evident in many tissues, including cytokeratin 5-rich basal cells from stratified and pseudostratified epithelia, suggesting that the lentiviral vector might have reached progenitor cells. Conversely, we identified the presence of immune-inflammatory infiltrates in several EGFP-expressing tissues. Moreover, almost 70% of the lentiviral vector-treated rabbits elicited a humoral immune response against the viral envelope and/or the EGFP. Conclusions At two-thirds gestational age, the adaptive immune system of the rabbit appears a relevant factor limiting transgene persistence and expression following lentiviral vector-mediated in utero gene transfer. Copyright © 2008 John Wiley & Sons, Ltd. [source]


Human cytomegalovirus final envelopment on membranes containing both trans -Golgi network and endosomal markers

CELLULAR MICROBIOLOGY, Issue 3 2010
Victoria Cepeda
Summary The human cytomegalovirus (HCMV) has been shown to complete its final envelopment on cytoplasmic membranes prior to its secretion to the extracellular medium. However, the nature of these membranes has not been characterized. It is thought that HCMV acquires its final envelope from the trans -Golgi network (TGN), though we and others have previously reported a role for endocytic membranes. Here we studied the localization of cellular markers in HCMV-infected cells and in isolated viruses. Immunofluorescence staining indicated that HCMV induces the recruitment of TGN and endosomal markers to the virus factory. Immuno-gold labelling of isolated viral particles and electron microscopy demonstrated the incorporation of TGN46, endosomal markers early endosomal antigen 1, annexin I, transferrin receptor and CD63, and the cation-independent mannose 6-phosphate receptor, which traffics between the TGN and endosomes into the viral envelope. Virus immunoprecipitation assays demonstrated that virions containing TGN46 and CD63 were infectious. This study reconciles the apparent controversy regarding the nature of the HCMV assembly site and suggests that HCMV has the ability to generate a novel membrane compartment containing markers for both TGN and endosomes, or that the membranes that HCMV uses for its envelope may be vesicles in transit between the TGN and endosomes. [source]


The ESCRT machinery is not required for human cytomegalovirus envelopment

CELLULAR MICROBIOLOGY, Issue 12 2007
Alberto Fraile-Ramos
Summary The human cytomegalovirus (HCMV) has been proposed to complete its final envelopment on cytoplasmic membranes prior to its release to the extracellular medium. The nature of these membranes and the mechanisms involved in virus envelopment and release are poorly understood. Here we show by immunogold-labelling and electron microscopy that CD63, a marker of multivesicular bodies (MVBs), is incorporated into the viral envelope, supporting the notion that HCMV uses endocytic membranes for its envelopment. We therefore investigated a possible role for the cellular endosomal sorting complex required for transport (ESCRT) machinery in HCMV envelopment. Depletion of tumour suppressor gene 101 and ALIX/AIP1 with small interfering RNAs (siRNAs) in HCMV-infected cells did not affect virus production. In contrast, siRNAs against the vacuolar protein sorting 4 (VPS4) proteins silenced the expression of VPS4A and VPS4B, inhibited the sorting of epidermal growth factor to lysosomes, the formation of HIV Gag-derived virus-like particles and vesicular stomatitis virus infection, but enhanced the number of HCMV viral particles produced. Treatment of infected cells with protease inhibitors also increased viral production. These studies indicate that, in contrast to some enveloped RNA viruses, HCMV does not require the cellular ESCRT machinery to complete its envelopment. [source]