US 12,453,765 B2
Intrinsic system for viral vector transgene regulation
Michael Jarvis, Devon (GB); and Alec Redwood, Crawley (AU)
Assigned to THE VACCINE GROUP LIMITED, Plymouth (GB)
Appl. No. 17/607,573
Filed by THE VACCINE GROUP LIMITED, Plymouth (GB)
PCT Filed May 1, 2020, PCT No. PCT/EP2020/062196
§ 371(c)(1), (2) Date Oct. 29, 2021,
PCT Pub. No. WO2020/221923, PCT Pub. Date Nov. 5, 2020.
Claims priority of application No. 1906104 (GB), filed on May 1, 2019.
Prior Publication US 2022/0202925 A1, Jun. 30, 2022
Int. Cl. C12N 15/86 (2006.01); A61K 39/00 (2006.01); A61K 39/12 (2006.01); C12N 15/861 (2006.01); C12N 15/863 (2006.01); C12N 15/864 (2006.01); C12N 15/869 (2006.01)
CPC A61K 39/12 (2013.01) [A61K 39/00 (2013.01); A61K 39/0011 (2013.01); C12N 15/86 (2013.01); A61K 2039/5256 (2013.01); A61K 2039/552 (2013.01); C12N 2710/16134 (2013.01); C12N 2710/16143 (2013.01); C12N 2710/16162 (2013.01)] 4 Claims
 
1. A method for the regulated removal of heterologous genetic material from disseminating DNA viral vaccine vectors, comprising:
providing a wild-type or parental DNA viral vector which includes a wild-type or parental genomic sequence and a recombinantly engineered duplication of the said wild-type or parental genomic sequence;
providing a transgene expression cassette which comprises a transgene and the necessary regulatory genetic elements for control of transgene expression; and
inserting the transgene expression cassette into the DNA viral vector so that the transgene is flanked by the wild-type or parental genomic sequence and the recombinantly engineered duplication of wild-type or parental genomic sequence;
whereby homologous recombination between the flanking wild-type or parental genomic sequences subsequently results in removal of the transgene and restoration of only a single copy of the wild-type or parental genomic sequence as is normally found within a wild type or parental DNA virus, thereby regenerating the wild-type or parental DNA virus genome with an absence of any non-parental virus genetic sequence;
wherein the method comprises a step of selecting a length for the wild-type or parental genomic sequence to be duplicated; and
in which the rate of transgene removal from the viral genome, and hence reversion of recombinant virus genome to wild-type or parental, is a function of the length of the selected duplicated wild-type or parental genomic sequence.