Inhibitory effect of herpes simplex virus type 1 on type 2 virus replication

Area of Science:

• Virology
• Molecular Biology
• Cell Biology

Background:

• Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) are human pathogens with distinct biological properties.
• Understanding viral interactions is crucial for developing antiviral strategies.

Purpose of the Study:

• To investigate the interference phenomenon between HSV-1 and HSV-2 in cell cultures.
• To elucidate the mechanisms underlying HSV-1's inhibition of HSV-2 replication.

Main Methods:

• Simultaneous infection of chick embryo fibroblasts (CEF) and rabbit embryo fibroblasts (REF) with HSV-1 and HSV-2.
• Varying the multiplicity of infection (m.o.i.) for HSV-1.
• Assessing HSV-2 virus production.
• Utilizing ultraviolet (U.V.) irradiation to inactivate viruses and study genome function.

Main Results:

• Simultaneous HSV-1 and HSV-2 infection markedly reduced HSV-2 production in both CEF and REF cells.
• The inhibitory effect was dependent on a high m.o.i. of HSV-1.
• Interference diminished with longer intervals between HSV-2 and HSV-1 infections.
• U.V. inactivation of HSV-2 enhanced HSV-1's inhibitory effect, while U.V. inactivation of HSV-1 reduced its inhibitory activity.
• No evidence of interferon involvement was observed.

Conclusions:

• A functional HSV-1 genome, not interferon, is responsible for inhibiting HSV-2 production.
• An early step in HSV-2 replication is sensitive to a product encoded by the HSV-1 genome.