Herpes simplex virus-based vectors

Two types of HSV vectors are available for gene transfer into neurons, and both have been shown to be capable of delivering genes to a variety of cell types in the PNS and CNS of test animals.

Abstract

Herpes Simplex Virus (HSV) 1 and 2 are large DNA viruses with genomes of around 150 kb, which replicate in the nucleus of infected cells and infect sensory neurons. The development of herpes vectors has taken two routes. The first route has utilized deletions of essential genes and other genes involved in the production of cytopathic effects from the virus. The essential genes are complemented in culture allowing growth, but their absence from progeny virus renders them avirulent in vivo. The second approach, using defective viruses or amplicons, is based on a plasmid vector, allowing growth and genetic manipulation in bacteria, into which the potential transgene can be inserted. Two types of HSV vectors are available for gene transfer into neurons, and both of these have been shown to be capable of delivering genes to a variety of cell types in the PNS and CNS of test animals. It is suggested that the safety considerations for the use of an amplicon or a disabled virus in vivo are essentially identical, as the safety of an amplicon is dependent on the helper virus used.