What are herpes simplex viruses (HSVs) and why are they used as vectors?

The herpes simplex virus 1 and 2 are double-stranded DNA viruses responsible for the development of oral cold sores and the sexually-transmitted disease genital herpes in humans. Herpesviruses are highly cytotoxic, but also have the capacity to establish latent infections, particularly in neurons.¹ It is this neuronal transduction propensity that makes herpesviruses attractive vector candidates for neurological research.¹ In addition, herpesviruses grow well in tissue culture, enabling simple acquisition of high titres. The genomic foreign DNA capacity is large, and the genome is easily manipulated. All this makes herpesviruses attractive as viral vectors – provided that the virus’s innate pathogenicity, cytotoxicity, and latency-associated transcriptional repression can be overcome.¹

References:
1. R.H. Lachmann, “Herpes simplex virus-based vectors,” Int J Exp Pathol 85(4): 177-190, 2004.