Findings from a study published in the journal Science Translational Medicine; are offering new insights into neonatal herpes; its impact on developing nervous systems; and how newborns can be protected from the disease. When we hear the term herpes; many of us may first think of cold sores or perhaps genital infections. Both are; associated with the herpes simplex virus (HSV); a common infection of the nervous system which; while not curable, helped with antiviral drugs such as acyclovir.
Tragically, this is often not the case with a rarer and less recognized form of the disease: neonatal herpes; which can infect newborns with vulnerable immune systems, often leading to brain damage and death. “One problem in infants is that it’s very difficult to diagnose; often they’re antibiotics to treat what is; thought to be a bacterial infection;” explains Leib. “By the time the mistake realized; and they’re; given antivirals; it’s too late to save their lives; or to save their brains from long-term neurological damage. This can manifest as speech and learning problems; anxiety, motor issues, and problems with their hearing and vision.”
The efficacy of a live attenuated HSV vaccine
The work; supported, in part; by a National Institutes of Health-funded program project (grant number P01 AI098681) between Harvard and Dartmouth, with Harvard Medical School investigators Don Coen, Ph.D., and David Knipe, Ph.D. Leib also worked with Margie Ackerman, Ph.D., associate professor at Dartmouth’s Thayer School of Engineering, on the study. The researchers were able to test the efficacy of a live attenuated HSV vaccine from the Knipe Lab in a neonatal mouse model—by administering the vaccine to female mice, then mating those females to generate offspring.
“What we discovered was that when we challenged the newborn mice with virus; they were protected due to the mothers having been vaccinated;” says Leib. “Similarly, a different set of newborn mice were; protected after we gave their moms; a shot of HSV-specific antibodies.”So, we were able to show; that with both active and passive immunity administered to the mothers; we could protect the offspring; from this neurological disorder,” says Leib; who notes that the researchers were also able to obtain; human longitudinal serum samples from mothers, newborns, and young children to test for HSV antibodies and confirm the validity of their mouse model.
Constructing an open chamber with a GoPro camera
“They set up what’s called an open field test, by constructing an open chamber with a GoPro camera mounted on the top, so they could record the movements and behavior of the mice,” explains Leib. “What we found was that mice who were infected and not protected by their mothers had significantly higher levels of anxiety-like behavior, consistent with the idea that they had brain damage.” Notably, the researchers also observed considerable anxiety-like behavior in adult mice that had been infected with trace amounts of the virus as neonates, even though they showed no other clinical signs of disease. “I think what this tells us is that these naturally occurring viruses in our environment, which we may be exposed to as infants, have the possibility of affecting our behavior and our development over the long term,” he says.