Abstract
Background: Herpes simplex virus type 1 (HSV-1) amplicon vectors can be used to deliver transgenes to the nuclear environment of mammalian cells without cytotoxicity or pathogenic consequences for the inoculated organisms. Previous efforts describe a method of making helper virus-free amplicons (hf-HSV particles) or cells that contain those particles (e.g., packaging cell lines or patient's cells infected in vivo or ex vivo). Objective/methods: Described herein are several advances in hf-HSV particle technology that were designed to improve both production, by expressing viral proteins in trans (e.g., virion host shutoff protein and/or viral protein 16) during production, and also amplicon genome expression stability in the infected cells, by including a transposon-encoding system (e.g., the Tcl-like Sleeping Beauty transposon system). Results/conclusions: Improved titers and chromosomal integration of the transgene enhanced hf-HSV amplicon applications. Nevertheless, further studies will be needed to improve the safety of treatments using an integrating amplicon vector.
Acknowledgments
The authors thank Kyle Grant for critical reading of the manuscript.