Betanodavirus Quantification and IFN I-Antagonism Detection Using Luciferase Reporter Systems Based on Fish mx...

Area of Science:

• Aquaculture
• Virology
• Molecular Biology

Background:

• Mx genes are rapidly induced by viral infections, reflecting virus-host interactions.
• Viral immune evasion strategies often involve blocking Mx gene transcription.
• In vitro systems using Mx promoters can model these interactions.

Purpose of the Study:

• To develop and apply novel cell lines for studying betanodavirus-host interactions.
• To assess the utility of fish Mx promoter-driven luciferase systems for viral detection.
• To establish a method for quantifying viral load and its effects.

Main Methods:

• Development of RTG-2 cell lines with luciferase reporter genes under the control of Senegalese sole (ssmx) and gilthead sea bream (saumx2) promoters.
• Inoculation of these cell lines with different betanodavirus (NNV) genotypes.
• Establishment of a protocol to quantify NNV titres in fish brain tissue.

Main Results:

• Both cell line systems successfully detected various NNV isolates, with distinct induction profiles for each isolate.
• The study demonstrated a clear dose-dependent antagonistic effect of an NNV isolate on the reporter system.
• A reliable method for estimating NNV titres in sea bass brain was established.

Conclusions:

• The developed cell lines are valuable tools for investigating betanodavirus-host interactions.
• These systems aid in the detection and characterization of different NNV genotypes.
• The findings contribute to developing strategies to combat viral diseases in aquaculture.