Approaches that might effectively clear herpesviruses from the body are of considerable interest, as there is good evidence for the burden of persistent infection to have a meaningful impact on the pace of aging, largely via detrimental effects on the operation of the immune system over the course of years and decades. This is particularly true for cytomegalovirus, which may be a major cause of immunosenescence in near all people, but one might also look at the (presently disputed) evidence for HSV-1 to be a primary contributing cause of Alzheimer’s disease.

Infectious disease researchers have used a gene editing approach to remove latent herpes simplex virus 1, or HSV-1, also known as oral herpes. In animal models, the findings show at least a 90 percent decrease in the latent virus, enough researchers expect that it will keep the infection from coming back. The study used two sets of genetic scissors to damage the virus’s DNA, fine-tuned the delivery vehicle to the infected cells, and targeted the nerve pathways that connect the neck with the face and reach the tissue where the virus lies dormant in individuals with the infection.

In the study, the researchers used two types of genetic scissors to cut the DNA of the herpes virus. They found that when using just one pair of the scissors the virus DNA can be repaired in the infected cell. But by combining two scissors – two sets of gene-cutting proteins called meganucleases that zero in on and cut a segment of herpes DNA – the virus fell apart. The dual genetic scissors are introduced into the target cells by delivering the gene coding for the gene-cutting proteins with a vector, which is a harmless deactivated virus that can slip into infected cells. The researchers injected the delivery vector into a mouse model of HSV-1 infection, and it finds its way to the target cells after entering the nerve pathways. The researchers found a 92% reduction in the virus DNA present in the superior cervical ganglia, the nerve tissue where the virus lies dormant. The reductions remained for at least a month after the treatment.

“This is the first time that scientists have been able to go in and actually eliminate most of the herpes in a body. We are targeting the root cause of the infection: the infected cells where the virus lies dormant and are the seeds that give rise to repeat infections. Most research on herpes has focused on suppressing the recurrence of painful symptoms, and the team is taking a completely different approach by focusing on how to cure the disease. The big jump here is from doing this in test tubes to doing this in an animal. I hope this study changes the dialog around herpes research and opens up the idea that we can start thinking about cure, rather than just control of the virus.”