scholarly journals Zinc-finger antiviral protein (ZAP) is a restriction factor for replication of modified vaccinia virus Ankara (MVA) in human cells

2020 ◽  
Vol 16 (8) ◽  
pp. e1008845
Author(s):  
Chen Peng ◽  
Linda S. Wyatt ◽  
Shira G. Glushakow-Smith ◽  
Madhu Lal-Nag ◽  
Andrea S. Weisberg ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Zinc Finger ◽  
Human Cells ◽  
Restriction Factor ◽  
Antiviral Protein ◽  
Modified Vaccinia Virus Ankara

scholarly journals Repair of a previously uncharacterized second host-range gene contributes to full replication of modified vaccinia virus Ankara (MVA) in human cells

2020 ◽  
Vol 117 (7) ◽  
pp. 3759-3767 ◽  
Author(s):  
Chen Peng ◽  
Bernard Moss
Keyword(s):  
Vaccinia Virus ◽  
Host Range ◽  
Cell Lines ◽  
Chicken Embryo ◽  
A549 Cells ◽  
Human Cells ◽  
Modified Vaccinia Virus Ankara ◽  
Core Proteins ◽  
Embryo Fibroblasts ◽  
Chicken Embryo Fibroblasts

Modified vaccinia virus Ankara (MVA), a widely used vaccine vector for expression of genes of unrelated pathogens, is safe, immunogenic, and can incorporate large amounts of added DNA. MVA was derived by extensively passaging the chorioallantois vaccinia virus Ankara (CVA) vaccine strain in chicken embryo fibroblasts during which numerous mutations and deletions occurred with loss of replicative ability in most mammalian cells. Restoration of the deleted C12L gene, encoding serine protease inhibitor 1, enhances replication of MVA in human MRC-5 cells but only slightly in other human cells. Here we show that repair of the inactivated C16L/B22R gene of MVA enhances replication in numerous human cell lines. This previously uncharacterized gene is present at both ends of the genome of many orthopoxviruses and is highly conserved in most, including smallpox and monkeypox viruses. The C16L/B22R gene is expressed early in infection from the second methionine of the previously annotated Copenhagen strain open reading frame (ORF) as a 17.4-kDa protein. The C16/B22 and C12 proteins together promote MVA replication in human cells to levels that are comparable to titers in chicken embryo fibroblasts. Both proteins enhance virion assembly, but C16/B22 increases proteolytic processing of core proteins in A549 cells consistent with higher infectious virus titers. Furthermore, human A549 cells expressing codon-optimized C16L/B22R and C12L genes support higher levels of MVA replication than cell lines expressing neither or either alone. Identification of the genes responsible for the host-range defect of MVA may allow more rational engineering of vaccines for efficacy, safety, and propagation.

scholarly journals Double-stranded RNA-binding protein E3 controls translation of viral intermediate RNA, marking an essential step in the life cycle of modified vaccinia virus Ankara

2006 ◽  
Vol 87 (5) ◽  
pp. 1145-1155 ◽  
Author(s):  
Holger Ludwig ◽  
Yasemin Suezer ◽  
Zoe Waibler ◽  
Ulrich Kalinke ◽  
Barbara S. Schnierle ◽  
...  
Keyword(s):  
Life Cycle ◽  
Vaccinia Virus ◽  
Human Cells ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Rnase L ◽  
Oligoadenylate Synthetase ◽  
Double Stranded Rna ◽  
Modified Vaccinia Virus Ankara ◽  
Late Transcription

Infection of human cells with modified vaccinia virus Ankara (MVA) activates the typical cascade-like pattern of viral early-, intermediate- and late-gene expression. In contrast, infection of human HeLa cells with MVA deleted of the E3L gene (MVA-ΔE3L) results in high-level synthesis of intermediate RNA, but lacks viral late transcription. The viral E3 protein is thought to bind double-stranded RNA (dsRNA) and to act as an inhibitor of dsRNA-activated 2′-5′-oligoadenylate synthetase (2′-5′OA synthetase)/RNase L and protein kinase (PKR). Here, it is demonstrated that viral intermediate RNA can form RNase A/T1-resistant dsRNA, suggestive of activating both the 2′-5′OA synthetase/RNase L pathway and PKR in various human cell lines. Western blot analysis revealed that failure of late transcription in the absence of E3L function resulted from the deficiency to produce essential viral intermediate proteins, as demonstrated for vaccinia late transcription factor 2 (VLTF 2). Substantial host cell-specific differences were found in the level of activation of either RNase L or PKR. However, both rRNA degradation and phosphorylation of eukaryotic translation initiation factor-2α (eIF2α) inhibited the synthesis of VLTF 2 in human cells. Moreover, intermediate VLTF 2 and late-protein production were restored in MVA-ΔE3L-infected mouse embryonic fibroblasts from Pkr 0/0 mice. Thus, both host-response pathways may be involved, but activity of PKR is sufficient to block the MVA molecular life cycle. These data imply that an essential function of vaccinia virus E3L is to secure translation of intermediate RNA and, thereby, expression of other viral genes.

scholarly journals Differences in Virus-Induced Cell Morphology and in Virus Maturation between MVA and Other Strains (WR, Ankara, and NYCBH) of Vaccinia Virus in Infected Human Cells

2003 ◽  
Vol 77 (19) ◽  
pp. 10606-10622 ◽  
Author(s):  
Juan Carlos Gallego-Gómez ◽  
Cristina Risco ◽  
Dolores Rodríguez ◽  
Pilar Cabezas ◽  
Susana Guerra ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
New York ◽  
Vaccinia Virus ◽  
Hela Cells ◽  
Morphological Changes ◽  
Human Cells ◽  
The Other ◽  
Transmission Electron Microscopy Analysis ◽  
Modified Vaccinia Virus Ankara ◽  
Electron Microscopy Analysis

ABSTRACT Live recombinants based on attenuated modified vaccinia virus Ankara (MVA) are potential vaccine candidates against a broad spectrum of diseases and tumors. To better understand the efficacy of MVA as a human vaccine, we analyzed by confocal and electron microscopy approaches MVA-induced morphological changes and morphogenetic stages during infection of human HeLa cells in comparison to other strains of vaccinia virus (VV): the wild-type Western Reserve (WR), Ankara, and the New York City Board of Health (NYCBH) strains. Confocal microscopy studies revealed that MVA infection alters the cytoskeleton producing elongated cells (bipolar), which do not form the characteristic actin tails. Few virions are detected in the projections connecting neighboring cells. In contrast, cells infected with the WR, Ankara, and NYCBH strains exhibit a stellated (multipolar) or rounded morphology with actin tails. A detailed transmission electron microscopy analysis of HeLa cells infected with MVA showed important differences in fine ultrastructure and amounts of the viral intermediates compared to cells infected with the other VV strains. In HeLa cells infected with MVA, the most abundant viral forms are intracellular immature virus, with few intermediates reaching the intracellular mature virus (IMV) form, at various stages of maturation, which exhibit a more rounded shape than IMVs from cells infected with the other VV strains. The “IMVs” from MVA-infected cells have an abnormal internal structure (“atypical” viruses) with potential alterations in the core-envelope interactions and are unable to significantly acquire the additional double envelope to render intracellular envelope virus. The presence of potential cell-associated envelope virus is very scarce. Our findings revealed that MVA in human cells promotes characteristic morphological changes to the cells and is able to reach the IMV stage, but these virions were not structurally normal and the subsequent steps in the morphogenetic pathway are blocked.

scholarly journals Recombinant Modified Vaccinia Virus Ankara Generating Ebola Virus-Like Particles

2017 ◽  
Vol 91 (11) ◽  
Author(s):  
Marc Schweneker ◽  
Andrea S. Laimbacher ◽  
Gert Zimmer ◽  
Susanne Wagner ◽  
Elisabeth M. Schraner ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Viral Vectors ◽  
Matrix Protein ◽  
Ebola Virus ◽  
Virus Disease ◽  
Hemorrhagic Fever ◽  
Human Cells ◽  
Transient Expression Assay ◽  
Virus Like Particles ◽  
Modified Vaccinia Virus Ankara

ABSTRACT There are currently no approved therapeutics or vaccines to treat or protect against the severe hemorrhagic fever and death caused by Ebola virus (EBOV). Ebola virus-like particles (EBOV VLPs) consisting of the matrix protein VP40, the glycoprotein (GP), and the nucleoprotein (NP) are highly immunogenic and protective in nonhuman primates against Ebola virus disease (EVD). We have constructed a modified vaccinia virus Ankara-Bavarian Nordic (MVA-BN) recombinant coexpressing VP40 and GP of EBOV Mayinga and the NP of Taï Forest virus (TAFV) (MVA-BN-EBOV-VLP) to launch noninfectious EBOV VLPs as a second vaccine modality in the MVA-BN-EBOV-VLP-vaccinated organism. Human cells infected with either MVA-BN-EBOV-VLP or MVA-BN-EBOV-GP showed comparable GP expression levels and transport of complex N-glycosylated GP to the cell surface. Human cells infected with MVA-BN-EBOV-VLP produced large amounts of EBOV VLPs that were decorated with GP spikes but excluded the poxviral membrane protein B5, thus resembling authentic EBOV particles. The heterologous TAFV NP enhanced EBOV VP40-driven VLP formation with efficiency similar to that of the homologous EBOV NP in a transient-expression assay, and both NPs were incorporated into EBOV VLPs. EBOV GP-specific CD8 T cell responses were comparable between MVA-BN-EBOV-VLP- and MVA-BN-EBOV-GP-immunized mice. The levels of EBOV GP-specific neutralizing and binding antibodies, as well as GP-specific IgG1/IgG2a ratios induced by the two constructs, in mice were also similar, raising the question whether the quality rather than the quantity of the GP-specific antibody response might be altered by an EBOV VLP-generating MVA recombinant. IMPORTANCE The recent outbreak of Ebola virus (EBOV), claiming more than 11,000 lives, has underscored the need to advance the development of safe and effective filovirus vaccines. Virus-like particles (VLPs), as well as recombinant viral vectors, have proved to be promising vaccine candidates. Modified vaccinia virus Ankara-Bavarian Nordic (MVA-BN) is a safe and immunogenic vaccine vector with a large capacity to accommodate multiple foreign genes. In this study, we combined the advantages of VLPs and the MVA platform by generating a recombinant MVA-BN-EBOV-VLP that would produce noninfectious EBOV VLPs in the vaccinated individual. Our results show that human cells infected with MVA-BN-EBOV-VLP indeed formed and released EBOV VLPs, thus producing a highly authentic immunogen. MVA-BN-EBOV-VLP efficiently induced EBOV-specific humoral and cellular immune responses in vaccinated mice. These results are the basis for future advancements, e.g., by including antigens from various filoviral species to develop multivalent VLP-producing MVA-based filovirus vaccines.

Spontaneous and targeted mutations in the decapping enzyme enhance replication of modified vaccinia virus Ankara (MVA) in monkey cells

2021 ◽  
Author(s):  
Noam Erez ◽  
Linda S. Wyatt ◽  
Jeffrey L. Americo ◽  
Wei Xiao ◽  
Bernard Moss
Keyword(s):  
Amino Acid ◽  
Vaccinia Virus ◽  
Host Range ◽  
Active Site ◽  
Mammalian Cells ◽  
Human Cells ◽  
Spontaneous Mutations ◽  
Modified Vaccinia Virus Ankara ◽  
Decapping Enzyme ◽  
Active Site Mutations

Modified vaccinia virus Ankara (MVA) was derived by repeated passaging in chick fibroblasts, during which deletions and mutations rendered the virus unable to replicate in most mammalian cells. Marker rescue experiments demonstrated that the host range defect could be overcome by replacing DNA that had been deleted from near the left end of the genome. One virus isolate, however, recovered the ability to replicate in monkey BS-C-1 cells but not human cells without added DNA suggesting it arose from a spontaneous mutation. Here we showed that variants with enhanced ability to replicate in BS-C-1 cells could be isolated by blind passaging MVA and that in each there was a point mutation leading to an amino acid substitution in the D10 decapping enzyme. The sufficiency of these single mutations to enhance host range was confirmed by constructing recombinant viruses. The D10 mutations occurred at N- or C-terminal locations distal from the active site, suggesting an indirect effect on decapping or on another previously unknown role of D10. Although increased amounts of viral mRNA and proteins were found in BS-C-1 cells infected with the mutants compared to parental MVA, the increase was much less than the one to two logs higher virus yields. Nevertheless, a contributing role for diminished decapping in overcoming the host range defect was consistent with increased replication and viral protein synthesis in BS-C-1 cells infected with an MVA engineered to have active site mutations that abrogate decapping activity entirely. Optimal decapping may vary depending on the biological context. IMPORTANCE Modified vaccinia virus Ankara (MVA) is an attenuated virus that is approved as a smallpox vaccine and is in clinical trials as a vector for other pathogens. The safety of MVA is due in large part to its inability to replicate in mammalian cells. Although, host-range restriction is considered a stable feature of the virus, we describe the occurrence of spontaneous mutations in MVA that increase replication considerably in monkey BS-C-1 cells but only slightly in human cells. The mutants contain single nucleotide changes that lead to amino acid substitutions in one of the two decapping enzymes. Although the spontaneous mutations are distant from the decapping enzyme active site, engineered active site-mutations also increased virus replication in BS-C-1 cells. The effects of these mutations on the immunogenicity of MVA vectors remain to be determined.

scholarly journals Recombinant Modified Vaccinia Virus Ankara (MVA) Vaccines Efficiently Protect Cockatiels Against Parrot Bornavirus Infection and Proventricular Dilatation Disease

Viruses ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1130 ◽  
Author(s):  
Isabell Rall ◽  
Ralf Amann ◽  
Sara Malberg ◽  
Christiane Herden ◽  
Dennis Rubbenstroth
Keyword(s):  
Vaccinia Virus ◽  
Challenge Infection ◽  
Control Group ◽  
Viral Loads ◽  
Breeding Populations ◽  
Modified Vaccinia Virus Ankara ◽  
Associated Lesions ◽  
Unvaccinated Control ◽  
Causative Agents ◽  
Proventricular Dilatation Disease

Parrot bornaviruses (PaBVs) are the causative agents of proventricular dilatation disease (PDD), a chronic and often fatal neurologic disorder in Psittaciformes. The disease is widely distributed in private parrot collections and threatens breeding populations of endangered species. Thus, immunoprophylaxis strategies are urgently needed. In previous studies we demonstrated a prime-boost vaccination regime using modified vaccinia virus Ankara (MVA) and Newcastle disease virus (NDV) constructs expressing the nucleoprotein and phosphoprotein of PaBV-4 (MVA/PaBV-4 and NDV/PaBV-4, respectively) to protect cockatiels (Nymphicus hollandicus) against experimental challenge infection. Here we investigated the protective effect provided by repeated immunization with either MVA/PaBV-4, NDV/PaBV-4 or Orf virus constructs (ORFV/PaBV-4) individually. While MVA/PaBV-4-vaccinated cockatiels were completely protected against subsequent PaBV-2 challenge infection and PDD-associated lesions, the course of the challenge infection in NDV/PaBV-4- or ORFV/PaBV-4-vaccinated birds did not differ from the unvaccinated control group. We further investigated the effect of vaccination on persistently PaBV-4-infected cockatiels. Remarkably, subsequent immunization with MVA/PaBV-4 and NDV/PaBV-4 neither induced obvious immunopathogenesis exacerbating the disease nor reduced viral loads in the infected birds. In summary, we demonstrated that vaccination with MVA/PaBV-4 alone is sufficient to efficiently prevent PaBV-2 challenge infection in cockatiels, providing a suitable vaccine candidate against avian bornavirus infection and bornavirus-induced PDD.

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