This invention relates to a VAC-BAC shuttle vector system for the creation of recombinant poxviruses from DNA cloned in a bacterial artificial chromosome. A VAC-BAC is a bacterial artificial chromosome (BAC) containing a vaccinia virus genome (VAC) that can replicate in bacteria and produce infectious virus in mammalian cells.
- VAC-BACs can be used to modify vaccinia virus DNA by deletion, insertion or point mutation or add new DNA to the VAC genome with methods developed for bacterial plasmids, rather than by recombination in mammalian cells.
- It can be used to produce recombinant vaccinia viruses for gene expression.
- It can be used for the production of modified vaccinia viruses that have improved safety or immunogenicity.
- VAC-BACs are clonally purified from bacterial colonies before virus reconstitution in mammalian cells.
- Manipulation of DNA is much simpler and faster in bacteria than in mammalian cells.
- Modified genomes can be characterized prior to virus reconstitution.
- Only virus with modified genomes will be produced so that virus plaque isolations are not needed.
- Generation of a stock of virus from a VAC-BAC is accomplished within a week rather than many weeks.
- Multiple viruses can be generated at the same time since plaque purification is unnecessary.