A spike-binding protein as a versatile tool to detect and inhibit transmissible gastroenteritis virus

Area of Science:

• Virology
• Molecular Biology
• Protein Engineering

Background:

• Coronaviruses (CoVs) Spike proteins are crucial for viral entry and are key targets for immune responses.
• Extensive research tools exist for beta-CoVs, but limited options are available for studying alpha-CoVs, including zoonotic strains.
• Transmissible gastroenteritis virus (TGEV) is a significant porcine alpha-CoV, necessitating better research tools.

Purpose of the Study:

• To develop and validate a pseudovirus system for studying alpha-CoV, specifically TGEV, viral entry.
• To identify novel ligands that bind to the TGEV Spike protein.
• To explore potential alternatives to antibodies for detecting alpha-CoVs.

Main Methods:

• Development and validation of a TGEV pseudovirus system.
• Phage display screening of an 'alpha-Reps' library to identify binding ligands.
• Characterization of identified ligands for their ability to bind the TGEV Spike protein and inhibit viral entry.

Main Results:

• A functional pseudovirus system for studying TGEV entry was successfully established.
• A specific alpha-Rep, designated TGE-D9, was identified that binds to the TGEV Spike protein (S1-TGEV-Fc construct).
• TGE-D9 demonstrated dose-dependent inhibition of pseudo-TGEV entry and bound to Spike proteins on viral particles.

Conclusions:

• The developed pseudovirus system offers a valuable tool for alpha-CoV research.
• TGE-D9 represents a promising synthetic ligand for studying TGEV and potentially other alpha-CoVs.
• These findings facilitate further structural and functional studies of alpha-CoV Spike proteins and their interactions.