Merck + Co., Inc.

Advec, Inc.

Robin Parks

Frank L Graham

Philip Ng

Liane Chen

The present invention relates to methods for efficient and reliable construction of adenovirus vectors which contain and express foreign DNA and are useful for gene transfer into mammalian cells, for vaccines and for gene therapy. The invention provides for the growth and purification of adenovirus vectors (helper dependent vectors or HDVs) from which all or most of the viral genes have been removed. The vector system described herein is a new method designed to eliminate helper viruses from the final HDV preparation by cleavage of the helper virus DNA with an endonuclease, alone or in combination with other methods known to limit the level of helper virus contamination of helper dependent vector preparations. The disclosed methods and compositions also provide for regulated control of gene expression.

System for production of helper dependent adenovirus vectors based on use of endonucleases

In the present invention, viruses, plasmids or both are constructed which contain viral DNA and lox sites positioned such that site-specific recombination between lox sites in separate plasmids results in generation of infectious viral DNA at high-efficiency in cotransfected host cells that have been engineered to express the Cre recombinase. Because of the high-efficiency and specificity of the Cre enzyme, suitably engineered plasmids can be readily recombined to produce infectious virus at high-efficiency in cotransfected 293 cells, without, at the same time, producing wild-type adenovirus, with the attendant problems for removal thereof. Use of recombinases besides Cre and recombinase recognition sites besides lox sites, and use of cells other than 293 cells are also disclosed and enabled, as are kits incorporating the site-specific vector system.

Recombinase-based system for combustion of adenovirus vectors

In the present invention, viruses, plasmids or both are constructed which contain viral DNA, at least one head-to-head ITR junction, and recombinase recognition sites positioned such that site-specific recombination between recombinase recognition sites in separate plasmids results in generation of infectious viral DNA at high-efficiency in cotransfected host cells that have been engineered to express a site-specific recombinase. Because of the high-efficiency and specificity of the Cre enzyme, suitably engineered plasmids can be readily recombined to produce infectious virus at high-efficiency in cotransfected 293 cells, without, at the same time, producing wild-type adenovirus, with the attendant problems for removal thereof. Use of recombinases besides Cre and recombinase recognition sites besides lox sites, and use of cells other than 293 cells are also disclosed and enabled, as are kits incorporating the site-specific vector system, as well as compositions and methods for using such compositions as vaccines or in gene therapeutic applications. Enhancement in the efficiency of site-specific recombination is provided by inclusion of a head-to-head ITR junction in each virus, plasmid, or other nucleic acid construct.

Enhanced system for construction of adenovirus vectors

This invention responds to a long felt need, by providing in one embodiment, a helper virus based on the Ad2 serotype for use in the Cre/loxP system for the generation of Ad vectors deleted of all Ad protein coding sequences. Using this and helper virus based on Ad5, genetically identical hdAd that differ only in the virion protein components, which are derived from the helper virus, were produced. The vectors have identical expression characteristics in vitro, regardless of the serotype, and the sequential use of hdAd of different serotypes allows for successful repeat vector administration in vivo.

Use of helper-dependent adenoviral vectors of alternative serotypes permits repeat vector administration

The present invention provides an improved helper-dependent vector system for production of high capacity adenoviral cloning vectors. The invention makes use of the DNA size packaging constraints imposed on a pIX-defective Ad virion that prevent such virions from packaging DNA larger than approximately 35 kb. This constraint can be used to develop helper viruses that do not package their DNA. In one embodiment, the invention combines this methodology with the Cre-loxP helper-dependent system to decrease the quantity of contaminating helper virus in vector preparations. In another embodiment the invention is used for vector growth.

Adenovirus vectors generated from helper viruses and helper-dependent vectors

In the present invention, viruses, plasmids or both are constructed which contain viral DNA and lox sites positioned such that site-specific recombination between lox sites in separate plasmids results in generation of infectious viral DNA at high-efficiency in cotransfected host cells that have been engineered to express the Cre recombinase. Because of the high-efficiency and specificity of the Cre enzyme, suitably engineered plasmids can be readily recombined to produce infectious virus at high-efficiency in cotransfected 293 cells, without, at the same time, producing wild-type adenovirus, with the attendant problems for removal thereof. Use of recombinases besides Cre and recombinase recognition sites besides lox sites, and use of cells other than 293 cells are also disclosed and enabled, as are kits incorporating the site-specific vector system, as well as compositions and methods for using such compositions as vaccines or in gene therapeutic applications.

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Ottawa, Canada

Robin Parks