Modified vaccinia Ankara strains with identical coding sequences actually represent complex mixtures of viruses that determine the biological properties of each strain

Suter, Mark; Meisinger-Henschel, Christine; Tzatzaris, Maria; Hülsemann, Vanessa; Lukassen, Susanne; Wulff, Niels; Hausmann, Jürgen; Howley, Paul M.; Chaplin, Paul

doi:10.1016/j.vaccine.2009.05.095

Cited by 59 publications

(61 citation statements)

References 20 publications

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“…In contrast, MVA B showed no replication in human cell lines (Fig. 3B), as expected from previous analysis (47). In Vero cells, which are semipermissive for MVA (30), all CVA mutants showed a very similar replication behavior, with no apparent alteration in replication capacity compared to CVA B (Fig.…”

Section: Cloning Of the Cva And Mva Genomes As Bacs And Reactivation supporting

confidence: 88%

Introduction of the Six Major Genomic Deletions of Modified Vaccinia Virus Ankara (MVA) into the Parental Vaccinia Virus Is Not Sufficient To Reproduce an MVA-Like Phenotype in Cell Culture and in Mice

Meisinger-Henschel

Späth

Lukassen

et al. 2010

J Virol

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Modified vaccinia virus Ankara (MVA) has a highly restricted host range in cell culture and is apathogenic in vivo. MVA was derived from the parental chorioallantois vaccinia virus Ankara (CVA) by more than 570 passages in chicken embryo fibroblast (CEF) cells. During CEF cell passaging, six major deletions comprising 24,668 nucleotides occurred in the CVA genome. We have cloned both the MVA and the parental CVA genome as bacterial artificial chromosomes (BACs) and have sequentially introduced the six major MVA deletions into the cloned CVA genome. Reconstituted mutant CVA viruses containing up to six major MVA deletions showed no detectable replication restriction in 12 of 14 mammalian cell lines tested; the exceptions were rabbit cell lines RK13 and SIRC. In mice, CVA mutants with up to three deletions showed slightly enhanced virulence, suggesting that gene deletion in replicating vaccinia virus (VACV) can result in gain of fitness in vivo. CVA mutants containing five or all six deletions were still pathogenic, with a moderate degree of attenuation. Deletion V was mainly responsible for the attenuated phenotype of these mutants. In conclusion, loss or truncation of all 31 open reading frames in the six major deletions is not sufficient to reproduce the specific MVA phenotype of strong attenuation and highly restricted host range. Mutations in viral genes outside or in association with the six major deletions appear to contribute significantly to this phenotype. Host range restriction and avirulence of MVA are most likely a cooperative effect of gene deletions and mutations involving the major deletions.

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Section: Cloning Of the Cva And Mva Genomes As Bacs And Reactivation supporting

confidence: 88%

Introduction of the Six Major Genomic Deletions of Modified Vaccinia Virus Ankara (MVA) into the Parental Vaccinia Virus Is Not Sufficient To Reproduce an MVA-Like Phenotype in Cell Culture and in Mice

Meisinger-Henschel

Späth

Lukassen

et al. 2010

J Virol

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“…It was subsequently named MVA due to its novel properties, and it was shown that MVA could be administered safely to animals and humans (35,45). MVA-BN was further developed from MVA of passage number 572 by limiting dilution and passaging and proved to be safe even in severely immunocompromised hosts (29,46). Recent clinical studies using MVA-BN as a third-generation standalone smallpox vaccine confirmed its excellent safety profile in humans (50,51) and underscored its potential as a safe vaccine and gene therapy vector.…”

mentioning

confidence: 99%

Immediate-Early Expression of a Recombinant Antigen by Modified Vaccinia Virus Ankara Breaks the Immunodominance of Strong Vector-Specific B8R Antigen in Acute and Memory CD8 T-Cell Responses

Baur

Brinkmann

Schweneker

et al. 2010

J Virol

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Efficient T-cell responses against recombinant antigens expressed by vaccinia virus vectors require expression of these antigens in the early phase of the virus replication cycle. The kinetics of recombinant gene expression in poxviruses are largely determined by the promoter chosen. We used the highly attenuated modified vaccinia virus Ankara (MVA) to determine the role of promoters in the induction of CD8 T-cell responses. We constructed MVA recombinants expressing either enhanced green fluorescent protein (EGFP) or chicken ovalbumin (OVA), each under the control of a hybrid early-late promoter (pHyb) containing five copies of a strong early element or the well-known early-late p7.5 or pS promoter for comparison. In primary or cultured cells, EGFP expression under the control of pHyb was detected within 30 min, as an immediateearly protein, and remained higher over the first 6 h of infection than p7.5-or pS-driven EGFP expression. Repeated immunizations of mice with recombinant MVA expressing OVA under the control of the pHyb promoter led to superior acute and memory CD8 T-cell responses compared to those to p7.5-and pS-driven OVA. Moreover, OVA expressed under the control of pHyb replaced the MVA-derived B8R protein as the immunodominant CD8 T-cell antigen after three or more immunizations. This is the first demonstration of an immediate-early neoantigen expressed by a poxviral vector resulting in superior induction of neoantigenspecific CD8 T-cell responses.

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“…In some cases, these might be laboratory contaminations with vaccinia virus, or may represent natural heterogeneity on a more limited scale than that recently observed in a strain of vaccinia virus, which was revealed by deep sequencing to be a complex, genetically diverse mixture [36]. Replication on human cell lines was not observed using clonal MVA with a genome identical to the five published sequences (see above) [33], suggesting that this phenotype is indeed representative of MVA as defined by this genomic sequence. Nevertheless, the requirement to test toxicity of novel MVA recombinants in mice prior to human clinical trials, although primarily aimed at confirming safety of the transgene product, may to some extent be additionally warranted from a virological viewpoint.…”

Section: Myth: Mva Replicates In Human Cellsmentioning

confidence: 92%

“…It is possible that these discrepancies are the result of minor contaminating viruses present in some non-clonal MVA stocks [33]. In some cases, these might be laboratory contaminations with vaccinia virus, or may represent natural heterogeneity on a more limited scale than that recently observed in a strain of vaccinia virus, which was revealed by deep sequencing to be a complex, genetically diverse mixture [36].…”

Section: Myth: Mva Replicates In Human Cellsmentioning

confidence: 99%

“…Taking first the viral genome, it is remarkable that five genomic sequences of independent MVA isolates from different laboratories are identical (with the exception of variable-length repeat regions). These are the original description [32] (GenBank U94848.1; note the published erratum); the Acambis 3000 strain deposited by the CDC (GenBank AY603355); MVA-I721 (GenBank DQ983236) and MVA-BN ® (GenBank DQ983238) deposited by Bavarian-Nordic GmbH [33]; and a bacterial artificial chromosome clone of MVA [34]. This provides confirmation of Mayr's original conclusion that MVA was stable after 570 passages in CEFs [35], although it has been suggested that there may be very minor contaminants in MVA stocks that have not been purified by limiting dilution or plaque-picking [33], in common with vaccinia virus strains [36].…”

Section: Myth: Mva Is Genetically Unstablementioning

confidence: 99%

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Recombinant MVA vaccines: dispelling the myths

Cottingham

Carroll²

2013

Vaccine

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Modified vaccinia Ankara strains with identical coding sequences actually represent complex mixtures of viruses that determine the biological properties of each strain

Cited by 59 publications

References 20 publications

Introduction of the Six Major Genomic Deletions of Modified Vaccinia Virus Ankara (MVA) into the Parental Vaccinia Virus Is Not Sufficient To Reproduce an MVA-Like Phenotype in Cell Culture and in Mice

Introduction of the Six Major Genomic Deletions of Modified Vaccinia Virus Ankara (MVA) into the Parental Vaccinia Virus Is Not Sufficient To Reproduce an MVA-Like Phenotype in Cell Culture and in Mice

Immediate-Early Expression of a Recombinant Antigen by Modified Vaccinia Virus Ankara Breaks the Immunodominance of Strong Vector-Specific B8R Antigen in Acute and Memory CD8 T-Cell Responses

Recombinant MVA vaccines: dispelling the myths

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