Modified vaccinia Ankara strains with identical coding sequences actually represent complex mixtures of viruses that determine the biological properties of each strain.
Modified vaccinia Ankara (MVA) was developed by serial passages on chicken embryo fibroblast cells. After passage 570, the virus was considered homogenous and genetically stable. Three MVA strains (MVA-572, MVA-I721 and MVA-BN) have been analyzed and shown to be 100% genetically identical; although significant differences in their phenotypes were illustrated. All MVA strains except MVA-BN replicated in human cells, or killed immune suppressed mice. Viruses isolated from dead animals were shown to represent variants present within MVA-572 or MVA-I721 used to inoculate the mice. These subpopulations were shown to encode mutations, or contain less than the six deletions associated with MVA and had significantly altered phenotypes compared to the parental MVA strains. MVA is a complex polyclonal mixture of viruses, the composition of which governs the phenotype.
Suter
Mark
M
University of Zurich, Institute of Virology, Winterthurerstrasse 266a, 8057 Zürich, Switzerland.
Meisinger-Henschel
Christine
C
Tzatzaris
Maria
M
Hülsemann
Vanessa
V
Lukassen
Susanne
S
Wulff
Niels Holger
NH
Hausmann
Jürgen
J
Howley
Paul
P
Chaplin
Paul
P
D000818:Animals; D002642:Chick Embryo; D004279:DNA, Viral / Q000032:analysis; D005260:Female; D016679:Genome, Viral; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D010053:Ovary / Q000821:virology; D010641:Phenotype; D012692:Serial Passage; D014616:Vaccinia virus / Q000235:genetics* / Q000502:physiology*; D014776:Virus Cultivation; D014779:Virus Replication
D004279:DNA, Viral