Neurovirulent strains of herpes simplex virus type 1 are not necessarily competent for reactivatable latency

Area of Science:

• Virology
• Neuroscience
• Immunology

Background:

• Herpes simplex virus type 1 (HSV-1) establishes lifelong latency, primarily in sensory neurons.
• Reactivation of latent HSV-1 from trigeminal ganglia (TG) causes recurrent disease.
• The relationship between HSV-1 neurovirulence and the ability to establish reactivatable latency is not fully understood.

Purpose of the Study:

• To compare the ability of two neurovirulent HSV-1 strains (F and +GC (LPV) Miyama) to establish and maintain reactivatable latency in mouse TG.
• To investigate if neurovirulence correlates with the capacity for viral reactivation from latency.

Main Methods:

• Intranasal inoculation of mice with neurovirulent HSV-1 strains F and +GC (LPV) Miyama.
• Explant cultures of trigeminal ganglia (TG) to assess HSV-1 reactivation.
• Quantification of viral reactivation rates.

Main Results:

• The F strain demonstrated a high rate of HSV-1 reactivation from TG.
• +GC (LPV) Miyama strain exhibited a very low rate of virus reactivation.
• Significant differences in reactivatable latency were observed between the two neurovirulent strains.

Conclusions:

• Neurovirulent HSV-1 strains are not uniformly competent for establishing reactivatable latency.
• The capacity for reactivation from latency may be strain-dependent, irrespective of neurovirulence.
• These findings challenge the assumption that highly virulent HSV-1 strains are always capable of maintaining reactivatable latency.