Gene delivery using helper virus-free HSV-1 amplicon vectors

Area of Science:

• Molecular Virology
• Gene Therapy Vectors
• Herpes Simplex Virus Research

Background:

• Herpes simplex virus type 1 (HSV-1)-based amplicon vectors require helper functions for replication and packaging.
• Traditional methods rely on replication-defective mutants or packaging-defective HSV-1 genomes.

Purpose of the Study:

• To describe a method for generating high-titer HSV-1 amplicon stocks.
• To produce amplicon vectors free of contaminating helper virus.

Main Methods:

• Utilizing packaging-defective HSV-1 genomes reconstituted from cosmids or BACs to provide helper functions.
• Cotransfection of amplicon DNA and cosmid/BAC DNA into 2-2 cells via cationic liposome-mediated transfection.
• Harvesting packaged amplicon vector particles and determining their titers.

Main Results:

• Reconstitution of HSV-1 genomes lacking DNA cleavage/packaging signals provides essential helper functions.
• This approach enables the packaging of cotransfected amplicon DNA.
• Resulting amplicon stocks are essentially free of contaminating helper virus, achieving high titers.

Conclusions:

• Packaging-defective HSV-1 genomes are effective for producing high-titer amplicon vectors.
• This method offers a significant advantage by eliminating helper virus contamination.
• The described protocol facilitates the generation of pure and potent HSV-1 amplicon stocks for research and therapeutic applications.