Nanobody-based retargeting of an oncolytic herpesvirus for eliminating CXCR4 GBM cells: A proof of principle.

Glioblastoma (GBM) is the most aggressive primary brain tumor in adults, which remains difficult to cure. The very high recurrence rate has been partly attributed to the presence of GBM stem-like cells (GSCs) within the tumors, which have been associated with elevated chemokine receptor 4 (CXCR4) expression. CXCR4 is frequently overexpressed in cancer tissues, including GBM, and usually correlates with a poor prognosis.

Varicella-Zoster Virus ORF9p Binding to Cellular Adaptor Protein Complex 1 Is Important for Viral Infectivity.

ORF9p (homologous to herpes simplex virus 1 [HSV-1] VP22) is a varicella-zoster virus (VZV) tegument protein essential for viral replication. Even though its precise functions are far from being fully described, a role in the secondary envelopment of the virus has long been suggested. We performed a yeast two-hybrid screen to identify cellular proteins interacting with ORF9p that might be important for this function.

Deletion of the ORF9p acidic cluster impairs the nuclear egress of varicella-zoster virus capsids.

The protein encoded by ORF9 is essential for varicella-zoster virus (VZV) replication. Previous studies documented its presence in the trans-Golgi network and its involvement in secondary envelopment. In this work, we deleted the ORF9p acidic cluster, destroying its interaction with ORF47p, and this resulted in a nuclear accumulation of both proteins.

Varicella-zoster virus induces the formation of dynamic nuclear capsid aggregates.

The first step of herpesviruses virion assembly occurs in the nucleus. However, the exact site where nucleocapsids are assembled, where the genome and the inner tegument are acquired, remains controversial. We created a recombinant VZV expressing ORF23 (homologous to HSV-1 VP26) fused to the eGFP and dually fluorescent viruses with a tegument protein additionally fused to a red tag (ORF9, ORF21 and ORF22 corresponding to HSV-1 UL49, UL37 and UL36).

ORF9p phosphorylation by ORF47p is crucial for the formation and egress of varicella-zoster virus viral particles.

The role of the tegument during the herpesvirus lytic cycle is still not clearly established, particularly at the late phase of infection, when the newly produced viral particles need to be fully assembled before being released from the infected cell. The varicella-zoster virus (VZV) protein coded by open reading frame (ORF) 9 (ORF9p) is an essential tegument protein, and, even though its mRNA is the most expressed during the productive infection, little is known about its functions. Using a GalK positive/negative selection technique, we modified a bacterial artificial chromosome (BAC) containing the complete VZV genome to create viruses expressing mutant versions of ORF9p.

The varicella-zoster virus ORF47 kinase interferes with host innate immune response by inhibiting the activation of IRF3.

The innate immune response constitutes the first line of host defence that limits viral spread and plays an important role in the activation of adaptive immune response. Viral components are recognized by specific host pathogen recognition receptors triggering the activation of IRF3. IRF3, along with NF-κB, is a key regulator of IFN-β expression.

The Varicella-Zoster virus IE4 protein: a conserved member of the herpesviral mRNA export factors family and a potential alternative target in antiherpetic therapies.

During a viral infection, in addition to cellular mRNAs, amounts of viral mRNAs have to be efficiently transported to the cytoplasm for translation. It is now established that herpesviruses encode a conserved gene family whose proteins act as viral mRNA export factors that mediate nucleocytoplasmic transport of viral transcripts and eventually modulate through this mechanism the antiviral response. This conserved family of proteins contains the IE4 protein of the Varicella-Zoster virus (VZV).

Innate immune response and viral interference strategies developed by human herpesviruses.

Viruses are by far the most abundant parasites on earth and they have been found to infect animals, plants and bacteria. However, different types of viruses can only infect a limited range of hosts and many are species-specific. Herpesviruses constitute a large family of DNA viruses that cause diseases in animals, including humans and that are known to undergo lytic or latent infections.

Varicella-zoster virus IE4 protein interacts with SR proteins and exports mRNAs through the TAP/NXF1 pathway.

Available data suggest that the Varicella-Zoster virus (VZV) IE4 protein acts as an important regulator on VZV and cellular genes expression and could exert its functions at post-transcriptional level. However, the molecular mechanisms supported by this protein are not yet fully characterized. In the present study, we have attempted to clarify this IE4-mediated gene regulation and identify some cellular partners of IE4.

Varicella vaccination in Europe - taking the practical approach.

Varicella is a common viral disease affecting almost the entire birth cohort. Although usually self-limiting, some cases of varicella can be serious, with 2 to 6% of cases attending a general practice resulting in complications. The hospitalisation rate for varicella in Europe ranges from 1.

Varicella vaccination in Japan, South Korea, and Europe.

The most extensive use of varicella vaccine has been in the United States and Canada, where it is universally recommended. However, a number of other countries now have recommendations for use of the vaccine, which has been expanding in Europe and Latin America. In this article, we review information concerning varicella vaccination in Japan, where the vaccine was first developed, and in South Korea and parts of Europe.

The varicella-zoster virus immediate-early 63 protein affects chromatin-controlled gene transcription in a cell-type dependent manner.

Background: Varicella Zoster Virus Immediate Early 63 protein (IE63) has been shown to be essential for VZV replication, and critical for latency establishment. The activity of the protein as a transcriptional regulator is not fully clear yet. Using transient transfection assays, IE63 has been shown to repress viral and cellular promoters containing typical TATA boxes by interacting with general transcription factors.

Varicella-zoster virus modulates NF-kappaB recruitment on selected cellular promoters.

Intercellular adhesion molecule 1 (ICAM-1) expression is down-regulated in the center of cutaneous varicella lesions despite the expression of proinflammatory cytokines such as gamma interferon and tumor necrosis factor alpha (TNF-alpha). To study the molecular basis of this down-regulation, the ICAM-1 induction of TNF-alpha was analyzed in varicella-zoster virus (VZV)-infected melanoma cells (MeWo), leading to the following observations: (i) VZV inhibits the stimulation of icam-1 mRNA synthesis; (ii) despite VZV-induced nuclear translocation of p65, p52, and c-Rel, p50 does not translocate in response to TNF-alpha; (iii) the nuclear p65 present in VZV-infected cells is no longer associated with p50 and is unable to bind the proximal NF-kappaB site of the icam-1 promoter, despite an increased acetylation and accessibility of the promoter in response to TNF-alpha; and (iv) VZV induces the nuclear accumulation of the NF-kappaB inhibitor p100. VZV also inhibits icam-1 stimulation of TNF-alpha by strongly reducing NF-kappaB nuclear translocation in MRC5 fibroblasts.

Increasing coverage and efficiency of measles, mumps, and rubella vaccine and introducing universal varicella vaccination in Europe: a role for the combined vaccine.

Universal mass vaccination according to a 2-dose measles-mumps-rubella (MMR) vaccine schedule is recommended by the World Health Organization and is fundamental to the control of these important diseases. Very high coverage (first dose, > or =95%; second dose, > or =80%) is necessary to achieve and sustain high population immunity, and eventually interrupt indigenous transmission of these diseases. In 2006, the Advisory Committee on Immunization Practices issued a recommendation for 2 doses of varicella vaccine to be given universally to children.

Varicella-zoster virus IE63 protein phosphorylation by roscovitine-sensitive cyclin-dependent kinases modulates its cellular localization and activity.

During the first stage of Varicella-Zoster virus (VZV) infection, IE63 (immediate early 63 protein) is mostly expressed in the nucleus and also slightly in the cytoplasm, and during latency, IE63 localizes in the cytoplasm quite exclusively. Because phosphorylation is known to regulate various cellular mechanisms, we investigated the impact of phosphorylation by roscovitine-sensitive cyclin-dependent kinase (RSC) on the localization and functional properties of IE63. We demonstrated first that IE63 was phosphorylated on Ser-224 in vitro by CDK1 and CDK5 but not by CDK2, CDK7, or CDK9.

Varicella-zoster virus IE63 protein represses the basal transcription machinery by disorganizing the pre-initiation complex.

Using transient transfection assays, regulation properties of varicella-zoster virus (VZV)-encoded IE63 protein were analyzed on several VZV immediate early (ORF4), early (ORF28) and late (ORF67) promoters. IE63 was shown to repress the basal activity of most of the promoters tested in epithelial (Vero) and neuronal (ND7) cells to various extents. Trans-repressing activities were also observed on heterologous viral and cellular promoters.

Regions of the varicella-zoster virus open reading frame 63 latency-associated protein important for replication in vitro are also critical for efficient establishment of latency.

Varicella-zoster virus (VZV) open reading frame 63 (ORF63) is one of the most abundant transcripts expressed during VZV latency in humans, and ORF63 protein has been detected in human ganglia by several laboratories. Deletion of over 90% of the ORF63 gene showed that the protein is required for efficient establishment of latency in rodents. We have constructed viruses with a series of mutations in ORF63.

Varicella-Zoster virus proteins encoded by open reading frames 14 and 67 are both dispensable for the establishment of latency in a rat model.

A rat model of Varicella-Zoster virus (VZV) provides a system in which to investigate the molecular determinants of viral latency in dorsal root ganglia (DRG). In this study, we determined whether the VZV glycoproteins gC and gI, corresponding to VZV open reading frames (ORFs) 14 and 67, respectively, were required for the establishment of latency in this model. A VZV gI deletion mutant (DeltagI) derived from a recombinant Oka (rOka) cosmid and a gC null mutant obtained from a clinical isolate were inoculated into the footpads of 6-week-old rats, and the presence of viral DNA and eight different VZV RNA transcripts corresponding to the three classes of genes was investigated by in situ RT-PCR amplification and in situ hybridization (ISH) in the DRG at 1 week, 1 month, and 18-24 months after infection.

Absence of intercellular adhesion molecule 1 expression in varicella zoster virus-infected keratinocytes during herpes zoster: another immune evasion strategy?

Downregulation of major histocompatibility complex (MHC) class I, MHC-II, and intercellular adhesion molecule 1 (ICAM-1) expression in infected cell lines allows some viruses to escape host immunity. In skin lesions of varicella zoster virus (VZV), MHC-II transcripts were demonstrated in keratinocytes around vesicles, but not in VZV-infected cells. Whether other immunoevasive mechanisms are present during herpes zoster (HZ) is not yet elucidated.

Atypical recurrent varicella in 4 patients with hemopathies.

Relapsing varicella may occur in children with HIV infection and more rarely in younger adults. Our aim was to report unusual clinical, histologic, and virologic aspects of 4 elderly patients with malignant hemopathies who had an unusual form of recurrent varicella develop. Conventional microscopy, immunohistochemistry, and in situ hybridization were applied to smears and skin biopsy specimens.

Phosphorylation of varicella-zoster virus IE63 protein by casein kinases influences its cellular localization and gene regulation activity.

During the early phase of varicella-zoster virus (VZV) infection, Immediate Early protein 63 (IE63) is expressed rapidly and abundantly in the nucleus, while during latency, this protein is confined mostly to the cytoplasm. Because phosphorylation is known to regulate many cellular events, we investigated the importance of this modification on the cellular localization of IE63 and on its regulatory properties. We demonstrate here that cellular casein kinases I and II are implicated in the in vitro and in vivo phosphorylation of IE63.