Biological and molecular aspects on herpes simplex virus latency

Area of Science:

• Virology
• Neuroscience
• Immunology

Background:

• Latent herpes simplex virus (HSV) infections in sensory neurons are the primary source of recurrent clinical herpetic outbreaks.
• Establishment of HSV latency involves complex viral and cellular factors, including neuroinvasiveness, receptor binding, infection permissiveness, and replication restriction.
• Existing hypotheses for HSV restriction in neurons include thymidine kinase deficient mutants, viral DNA hypermethylation, and latency-associated genes.

Purpose of the Study:

• To explore the mechanisms underlying the restriction of HSV infection within neurons.
• To investigate the role of superinfection in reactivating latent HSV infections.
• To elucidate the cellular and viral factors governing HSV latency and reactivation.

Main Methods:

• Analysis of hypotheses regarding HSV restriction, including thymidine kinase deficiency, DNA methylation, and latency-associated genes.
• Examination of reactivation mechanisms via superinfection with replication-incompetent and replication-competent HSV mutants.
• Investigation of cellular control mechanisms affecting HSV latency maintenance and reactivation.

Main Results:

• Reactivation by superinfection with replication-incompetent HSV mutants likely results from genetic complementation.
• Reactivation by replication-competent HSV requires multiple viral genome copies, suggesting the overcoming of cellular restriction.
• Cellular control mechanisms, susceptible to mechanical and chemical impairment, are crucial for maintaining latent HSV infection.

Conclusions:

• Reactivation of latent HSV is associated with the expression of latency-related viral genes (LAT).
• The establishment of HSV latency is influenced by viral genome properties and cellular restriction capacity.
• Cellular control plays a significant role in maintaining and potentially reactivating latent HSV infections.