The Experts below are selected from a list of 32373 Experts worldwide ranked by ideXlab platform
Shmuel Rozenblatt - One of the best experts on this subject based on the ideXlab platform.
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Replication-deficient Vaccinia virus encoding bacteriophage T7 RNA polymerase for transient gene expression in mammalian cells.
Virology, 1995Co-Authors: L S Wyatt, Shmuel RozenblattAbstract:The Vaccinia virus/bacteriophage T7 hybrid transient expression system employs a recombinant Vaccinia virus that encodes the T7 RNA polymerase gene, a plasmid vector with a gene of interest regulated by a T7 promoter, and any cell line suitable for infection and transfection. Although high expression in a majority of cells is achieved, the severe cytopathic effects of Vaccinia virus and the safety precautions required for use of infectious agents are undesirable features of the system. Here, we report the construction of a highly attenuated and avian host-restricted Vaccinia virus recombinant that encodes the T7 RNA polymerase gene (MVA/T7 pol) and demonstrate the use of the virus for transient expression in mammalian cells. MVA/T7 pol has reduced cytopathic effects compared to the previously used replication-competent Vaccinia virus, while providing a high level of gene expression in multiple mammalian cell lines.
Volker Erfle - One of the best experts on this subject based on the ideXlab platform.
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non replicating Vaccinia vector efficiently expresses bacteriophage t7 rna polymerase
FEBS Letters, 1995Co-Authors: Gerd Sutter, Marion Ohlmann, Volker ErfleAbstract:Modified Vaccinia virus Ankara (MVA), a host range restricted and highly attenuated Vaccinia virus strain, is unable to multiply in human and most other mammalian cell lines. Since viral gene expression is unimpaired in non-permissive cells recombinant MVA viruses are efficient as well as exceptionally safe expression vectors. We constructed a recombinant MVA that expresses the bacteriophage T7 RNA polymerase and tested its usefulness for transient expression of recombinant genes under the control of a T7 promoter. Using the chloramphenicol acetyltransferase (CAT) gene as a reporter gene, infection with MVA-T7pol allowed efficient synthesis of recombinant enzyme in mammalian cells. Despite the severe host restriction of MVA, enzyme activities induced by infection with MVA-T7pol were similar to those determined after infection with a replication-competent Vaccinia-T7pol recombinant virus. Thus, MVA-T7pol may be used as a novel Vaccinia vector to achieve T7 RNA polymerase-specific recombinant gene expression in the absence of productive Vaccinia virus replication.
L S Wyatt - One of the best experts on this subject based on the ideXlab platform.
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Replication-deficient Vaccinia virus encoding bacteriophage T7 RNA polymerase for transient gene expression in mammalian cells.
Virology, 1995Co-Authors: L S Wyatt, Shmuel RozenblattAbstract:The Vaccinia virus/bacteriophage T7 hybrid transient expression system employs a recombinant Vaccinia virus that encodes the T7 RNA polymerase gene, a plasmid vector with a gene of interest regulated by a T7 promoter, and any cell line suitable for infection and transfection. Although high expression in a majority of cells is achieved, the severe cytopathic effects of Vaccinia virus and the safety precautions required for use of infectious agents are undesirable features of the system. Here, we report the construction of a highly attenuated and avian host-restricted Vaccinia virus recombinant that encodes the T7 RNA polymerase gene (MVA/T7 pol) and demonstrate the use of the virus for transient expression in mammalian cells. MVA/T7 pol has reduced cytopathic effects compared to the previously used replication-competent Vaccinia virus, while providing a high level of gene expression in multiple mammalian cell lines.
Francis A Ennis - One of the best experts on this subject based on the ideXlab platform.
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cd4 t cells provide intermolecular help to generate robust antibody responses in Vaccinia virus vaccinated humans
Journal of Immunology, 2013Co-Authors: Liusong Yin, Sharon E. Frey, Francis A Ennis, Mauricio J Calvocalle, John Cruz, Frances K Newman, Lawrence J. SternAbstract:Immunization with Vaccinia virus elicits a protective Ab response that is almost completely CD4 + T cell dependent. A recent study in a rodent model observed a deterministic linkage between Ab and CD4 + T cell responses to particular Vaccinia virus proteins suggesting that CD4 + T cell help is preferentially provided to B cells with the same protein specificity (Sette et al. 2008. Immunity 28: 847–858). However, a causal linkage between Ab and CD4 + T cell responses to Vaccinia or any other large pathogen in humans has yet to be done. In this study, we measured the Ab and CD4 + T cell responses against four Vaccinia viral proteins (A27L, A33R, B5R, and L1R) known to be strongly targeted by humoral and cellular responses induced by Vaccinia virus vaccination in 90 recently vaccinated and 7 long-term Vaccinia-immunized human donors. Our data indicate that there is no direct linkage between Ab and CD4 + T cell responses against each individual protein in both short-term and long-term immunized donors. Together with the observation that the presence of immune responses to these four proteins is linked together within donors, our data suggest that in Vaccinia-immunized humans, individual viral proteins are not the primary recognition unit of CD4 + T cell help for B cells. Therefore, we have for the first time, to our knowledge, shown evidence that CD4 + T cells provide intermolecular (also known as noncognate or heterotypic) help to generate robust Ab responses against four Vaccinia viral proteins in humans.
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generation of recombinant Vaccinia viruses expressing puumala virus proteins and use in isolating cytotoxic t cells specific for puumala virus
Virus Research, 2002Co-Authors: Masanori Terajima, Heather L Van Epps, Anita M Leporati, Sarah E Juhlin, Jukka Mustonen, Antti Vaheri, Francis A EnnisAbstract:Abstract Puumala (PUU) virus causes a form of hemorrhagic fever with renal syndrome (HFRS), called nephropathia epidemica (NE), in Europe. HFRS is characterized by an increased capillary permeability, which we hypothesize is caused by hyperactivation of the host immune system, especially cellular immune responses. To identify cytotoxic T lymphocytes (CTLs) specific for the PUU virus from NE patients, we have made recombinant Vaccinia viruses expressing PUU virus proteins, the nucleocapsid (N) and two surface glycoproteins, G1 and G2. Recombinant Vaccinia viruses carrying the N or the first half of the G2 cDNA under the control of a strong synthetic promoter were made. To express G1 and the second half of the G2 proteins, however, we needed to use a T7 expression system, where the T7 RNA polymerase is produced from another recombinant vaccina virus co-infecting the same cells. These recombinant Vaccinia viruses were used to detect and clone PUU virus-specific CTLs from the peripheral blood mononuclear cells of NE patients. An HLA-A24-restricted CTL line recognizing the G2 protein was isolated and its 9-mer epitope was determined.
Erna Geessien Kroon - One of the best experts on this subject based on the ideXlab platform.
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An Update on the Known Host Range of the Brazilian Vaccinia Virus: An Outbreak in Buffalo Calves
Frontiers Media S.A., 2019Co-Authors: Mauricio Teixeira Lima, Jônatas Santos Abrahão, Graziele Pereira Oliveira, José Augusto Bastos Afonso, Rodolfo José Cavancanti Souto, Carla Lopes De Mendonça, Antonio Flavio Medeiros Dantas, Erna Geessien KroonAbstract:Even nearly forty years after the eradication of smallpox, members of the Poxviridae family continue to be the focus of an increasing number of studies. Among these studies, prominently stands Vaccinia virus, an orthopoxvirus that is associated with bovine Vaccinia outbreaks. Although more frequently associated with infections in cattle and humans, the host range of Vaccinia virus is not restricted only to these hosts. There are several instances of molecular and serological evidence of circulation of Vaccinia virus among wildlife species. In addition, viral isolation has confirmed a broad spectrum of Vaccinia virus hosts. In this report, we provide a brief update on the host range of Brazilian Vaccinia virus, and present a case description of an outbreak in domestic buffalo calves from Northeastern Brazil that corroborates previous serological and molecular studies. Furthermore, in the present study, Vaccinia virus has been isolated for the first time in buffaloes, and referred to as Vaccinia virus Pernambuco (VACV-PE). Phylogenetic reconstruction was based on A56R clustered VACV-PE with Vaccinia virus isolates belonging to group 1 Brazilian Vaccinia virus. Furthermore, the Vaccinia virus genome was detected in the milk of a lactating cow, which thereby revealed a pathway for future studies on the possible impact of Vaccinia virus on buffalo milk and milk products. Taken together, these results provide the first description of clinical disease caused by Vaccinia virus in buffaloes in South America. They also raise new questions about the chain of transmission of this virus
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brazilian Vaccinia virus strains are genetically divergent and differ from the lister vaccine strain
Microbes and Infection, 2008Co-Authors: Betânia Paiva Drumond, Juliana Almeida Leite, Flavio Guimaraes Da Fonseca, Claudio A Bonjardim, Paulo Cesar Peregrino Ferreira, Erna Geessien KroonAbstract:Vaccinia virus is responsible for an important zoonotic disease affecting dairy cattle and humans in Brazil, but little is known about the origin, epidemiology and evolution of these Brazilian Vaccinia virus strains. In this work, seven Brazilian Vaccinia virus strains and the Lister-derived Brazilian vaccine strain, named Lister-Butantan, were compared based on the sequences of ten host range and virulence related genes. Comparison of Brazilian Vaccinia virus strains with Lister-Butantan revealed several differences. Phylogenetic analyses confirmed the existence of genetically distinct Brazilian Vaccinia virus groups and has not thus far demonstrated a close relationship between Brazilian strains and Lister-Butantan. In this study, the BeAn58058 and SPAn232 strains were grouped together with the Belo Horizonte and Guarani P1 strains. Additionally, genetic polymorphisms in host range and virulence genes as well as differences in the deduced amino acid sequences were detected among Brazilian Vaccinia virus. This genetic diversity may result in a plethora of different biological properties presented by Brazilian Vaccinia virus, including differences in adaptation to the host as well as pathogenic properties. Furthermore, co-circulation of these divergent strains could increase the possibility of recombination events in nature, leading to the formation of new variants with unpredictable pathogenic potential.
