Herpes Simplex Virus 1 Coinfection Modifies Adeno-associated Virus Genome End Recombination

Abstract

Wildtype adeno-associated virus (AAV) can only replicate in the presence of helper factors, which can be provided by co-infecting helper viruses such as adenoviruses and herpes viruses. The AAV genome consists of a linear, single-stranded DNA (ssDNA), which is converted into different molecular structures within the host cell. Using high throughput sequencing we found that herpes simplex virus type 1 (HSV-1) co-infection leads to a shift in the type of AAV genome end recombination. In particular, open-end ITR recombination was enhanced whereas open-closed ITR recombination was reduced in the presence of HSV-1. We demonstrate that the HSV-1 protein ICP8 plays an essential role in HSV-1 mediated interference with AAV genome end recombination, indicating that the previously described ICP8-driven mechanism of HSV-1 genome recombination may be underlying the observed changes. We also provide evidence that additional factors, such as products of true late genes, are involved. Although HSV-1 co-infection significantly changed the type of AAV genome end recombination, no significant change in the amount of circular AAV genomes was identified. IMPORTANCE AAV-mediated gene therapy represents one of the most promising approaches for the treatment of genetic diseases. Currently, various GMP-compatible production methods can be applied to manufacture clinical grade vector, including methods that employ helper factors derived form HSV-1. Yet to date we do not fully understand how HSV-1 interacts with AAV. We observed that HSV-1 modulates AAV genome ends similarly to the genome recombination events observed during HSV-1 replication and postulate that further improvements of the HSV-1 production platform may enhance packaging of the recombinant AAV particles.

Characterization of the Human Blood Virome in Iranian Multiple Transfused Patients

“…This virus requires a coinfection with adenovirus or herpesvirus for its replication and can remain latent in human leukocytes [ 52 ]. Reactivation might coincide with a reduced immunocompetence and the reactivation of herpesviruses [ 53 ]. Although prevalent in the blood of healthy individuals, AAV does not seem to be an immediate concern for blood transfusion safety.…”

Current avenues of gene therapy in Pompe disease

“…Viral infection platforms, using insect baculovirus (rBV) or Human Herpes Simplex Type I virus (rHSV1) offer high yields per cell and are used in clinical trials [100,101]. rHSV1 coinfection modifies AAV genome-end recombination, emphasizing the need for improvement of rHSV-1 production [102 ▪ ]. The rBV system's limitations include loss of AAV particle infectivity, insect virus contamination of cell lines, differences in posttranslational modifications of the final product, which produce a negative impact on potency [101,103] Meanwhile, the rHSV system appears more versatile in producing highly infectious AAV regardless of serotype [92,93,104].…”