The human body employs internal mechanisms to resist viral infections, such as cytomegalovirus, through the production of defensive proteins that can block the activation of latent viruses and limit their spread.
A new study from the Weizmann Institute of Science indicates that higher baseline levels of these proteins in a cell increase the likelihood of preventing a viral invasion. The research, led by Dr. Michal Schwartz and published in the journal Nature Microbiology, focused on the human cytomegalovirus, a member of the herpes virus family.
When a virus enters a cell, it can take control of the protein production mechanisms, forcing the cell to produce multiple copies of itself. However, the study found that some cells produced higher levels of antiviral defenses prior to infection, preventing the virus from taking control. In contrast, cells with lower routine production of defense proteins were more susceptible to viral invasion.
The researchers monitored the infection process in immune cell groups—macrophages and their precursor cells—over 144 hours, sequencing RNA molecules from individual cells at various infection stages. They discovered that once cells began producing viral proteins, the process was irreversible, leading to viral genome replication and spread.
The study also revealed that mature macrophages, previously thought to only harbor active infections, could also contain latent viral infections. This suggests that various cell types previously believed to be exclusively subject to active infections may actually serve as unknown reservoirs for latent viruses.
Dr. Noam Stern-Ginossar emphasized that understanding the mechanisms determining whether disease manifests or the virus remains latent is crucial for developing effective treatments. The findings could lead to preventive therapies, particularly for immunocompromised patients and organ transplant recipients.