[Temperature sensitive mutant of Herpes simplex virus type 1. I. Pathogenicity and immunogenicity]

Area of Science:

• Virology
• Immunology
• Microbiology

Background:

• Herpes Simplex Virus 1 (HSV-1) is a common human pathogen.
• Understanding viral mutants is crucial for developing new therapeutic strategies.
• Temperature-sensitive (ts) mutants offer potential for attenuated vaccines.

Purpose of the Study:

• To characterize the biological features of a newly derived ts mutant of HSV-1.
• To assess the pathogenicity and immunogenicity of this ts mutant in murine models.
• To investigate the protective capabilities of the ts mutant against wild-type HSV-1 infection.

Main Methods:

• Derivation of a ts mutant of HSV-1 (McIntyre strain) through serial passages at a reduced temperature (28°C).
• Evaluation of pathogenicity by infecting inbred mouse lines (CFW/Pzh and BALB/cPzh) with the ts mutant and comparing with the wild-type strain propagated at 37°C.
• Assessment of immunogenic activity by challenging immunized mice with a highly virulent HSV-1 strain, including mice treated with the immunosuppressive agent Depo-Medrol.

Main Results:

• The ts mutant exhibited a statistically significant decrease in virulence compared to the native HSV-1 strain in both mouse lines.
• Mice immunized with the ts mutant were protected against subsequent infection with the virulent wild-type HSV-1.
• Even when mice received the immunosuppressive agent Depo-Medrol during immunization with the ts mutant, they still developed defense mechanisms against the native strain.

Conclusions:

• The characterized ts mutant of HSV-1 possesses significantly reduced virulence.
• The ts mutant demonstrates promising immunogenic properties, capable of inducing protective immunity against virulent HSV-1.
• The immunogenicity of the ts mutant is effective even under conditions of immunosuppression, suggesting a robust induction of defense mechanisms.