Re-evaluating natural resistance to herpes simplex virus type 1

Area of Science:

• Immunology
• Virology
• Genetics

Background:

• Innate resistance to herpes simplex virus type 1 (HSV-1) varies among individuals.
• Previous studies showed C57BL/6 mice are resistant to HSV-1 encephalitis, unlike BALB/c mice.
• The impact of this resistance on other stages of HSV-1 infection remained unclear.

Purpose of the Study:

• To investigate differences in HSV-1 pathogenesis, replication, spread, and latent infection establishment between resistant (C57BL/6) and susceptible (BALB/c) mouse strains.
• To clarify the mechanisms underlying differential susceptibility to HSV-1 infection.

Main Methods:

• Comparative analysis of HSV-1 infection dynamics in C57BL/6 and BALB/c mice.
• Assessment of viral entry, replication, spread, and establishment of latency.
• Evaluation of pathogenesis and mortality rates.

Main Results:

• C57BL/6 mice exhibit greater resistance to HSV-1 pathogenesis and mortality compared to BALB/c mice.
• HSV-1 enters, replicates, spreads, and establishes latent infections with nearly identical efficiency in both mouse strains.
• Despite differing disease outcomes, the fundamental infection process is conserved across strains.

Conclusions:

• Differences in natural resistance do not significantly impact HSV-1 replication, spread, or latency establishment.
• The observed resistance in C57BL/6 mice primarily affects pathogenesis, not the virus's ability to infect and persist.
• These findings question the relevance of natural resistance in explaining human herpes simplex virus (HSV) recurrence versus asymptomatic carriage.