How Does the Herpes Virus Spread Between Skin Cells?

For the experiment, the researchers used three-dimensional human skin organoids containing hair follicles and nerve-like cells. Unlike conventional cell cultures, this model makes it possible to study interactions between different cell types within a structure that closely resembles actual human skin.

The findings showed that the virus does not spread uniformly. During the early stages of infection, substantial amounts of the virus were detected in fibroblasts, the connective tissue cells of the dermis. Some epidermal and hair follicle cells contained less virus, even when neighboring cells were infected. The virus reached hair follicles and sensory neurons at later stages, suggesting that these cells may have some ability to resist infection.

Using spatial analysis of gene activity, the scientists also found that infected cells trigger different defensive responses. In particular, genes associated with the immune response to infection were activated, along with signaling molecules from the TNF family, which are involved in regulating immune processes.

The researchers hope that further experiments will help clarify how the body controls the virus before it enters the nervous system and why some cells are better at restricting infection than others.

HSV-1 typically causes cold sores on the lips and face. However, after the initial infection, it can remain dormant in the body, including in sensory nerve cells. In rare cases, the virus can cause a dangerous inflammation of the brain. Scientists are also investigating a possible link between HSV-1 and Alzheimer's disease, although the nature of this association and the virus's role in the development of the disease have not yet been established.