2',5'-oligoadenylate synthetase in interferon-alpha- and acyclovir-treated herpes simplex virus-infected cells

Area of Science:

• Virology
• Immunology
• Molecular Biology

Background:

• Interferon-alpha (IFN-alpha) exhibits antiviral properties against certain viruses via the 2',5'-oligoadenylate (2-5A) synthetase pathway.
• Herpes simplex virus (HSV) infections are a significant clinical concern, and combination therapies are explored for enhanced efficacy.

Purpose of the Study:

• To investigate the role of the 2-5A synthetase pathway in the antiviral activity of IFN-alpha against HSV.
• To determine if this pathway contributes to the synergistic anti-HSV effects of IFN-alpha combined with acyclovir (ACV).

Main Methods:

• Human corneal cells and Vero cells were treated with IFN-alpha and subsequently infected with HSV.
• 2-5A synthetase mRNA expression and enzyme production were quantified.
• Ribosomal RNA cleavage was assessed to detect endonuclease activation.
• Cellular enzyme activities were measured following treatment with IFN-alpha, ACV, or both.

Main Results:

• IFN-alpha treatment significantly upregulated 2-5A synthetase mRNA and enzyme production in both cell types.
• HSV infection alone did not induce 2-5A synthetase, but increased enzyme levels in IFN-alpha-treated cells, while decreasing mRNA levels.
• No activation of the latent endonuclease was observed despite high 2-5A synthetase levels.
• ACV treatment, alone or with IFN-alpha, did not enhance 2-5A synthetase or endonuclease activity.

Conclusions:

• The 2-5A synthetase pathway is inducible in corneal and Vero cells by IFN-alpha.
• This pathway does not appear to mediate the anti-HSV activity of IFN-alpha alone.
• The 2-5A synthetase pathway is not responsible for the synergistic antiviral effect observed with the combination of IFN-alpha and ACV.