Temperature-sensitive host range mutants of herpes simplex virus type 2.

Area of Science:

• Virology
• Molecular Biology
• Cell Biology

Background:

• Herpesviruses exhibit diverse infection mechanisms within host cells.
• Understanding early viral events is crucial for characterizing virus-host interactions.
• Herpes simplex virus type 2 (HSV-2) serves as a model for studying viral pathogenesis.

Purpose of the Study:

• To investigate early events determining virus-host cell interaction.
• To establish a system for analyzing temperature-sensitive mutants of HSV-2.
• To identify host cell factors influencing HSV-2 replication.

Main Methods:

• Isolation and characterization of four temperature-sensitive HSV-2 mutants.
• Assessment of viral replication and cytopathic effects in hamster embryo fibroblast (HEF) cells at 39°C.
• Complementation studies to identify temperature-sensitive viral functions.
• Replication assays in rabbit kidney (RK) cells at 39°C.

Main Results:

• Four HSV-2 mutants failed to induce cytopathic effects or replicate in HEF cells at 39°C.
• At least one mutant demonstrated a virus DNA-negative phenotype.
• Intracellular complementation confirmed temperature-sensitive viral functions.
• All mutants replicated efficiently in RK cells at 39°C, indicating host-range properties.

Conclusions:

• The isolated HSV-2 mutants are temperature-sensitive.
• These mutants exhibit host-range specificity, requiring a functional host cell factor absent in HEF cells.
• A specific host cell function, present in RK cells but not HEF cells at 39°C, is essential for mutant replication.