Anti-RBD Single-Chain Variable Fragments Library (scFv Library) Generation toward the Development of a Diagnostic...

Area of Science:

• Virology
• Immunology
• Biotechnology

Background:

• Emerging SARS-CoV-2 variants necessitate new therapeutic and diagnostic strategies.
• The spike protein's receptor-binding domain (RBD) is a key target for neutralizing antibodies due to its role in viral entry.
• Developing broadly reactive antibodies is crucial for combating current and future viral threats.

Purpose of the Study:

• To generate and characterize mouse-derived single-chain variable fragments (scFvs) targeting the SARS-CoV-2 spike protein RBD.
• To assess the epitope recognition and neutralizing activity of generated scFvs against SARS-CoV-2 variants.

Main Methods:

• Construction of a mouse single-chain variable fragment (scFv) phage display library against the SARS-CoV-2 RBD.
• Peptide ELISA-based epitope mapping to determine scFv binding sites and cross-reactivity.
• SARS-CoV-2 pseudovirus neutralization assays to evaluate the efficacy of selected scFvs.

Main Results:

• Selected monoclonal scFv phages demonstrated broad epitope recognition and reactivity across multiple SARS-CoV-2 variants.
• scFv C4 exhibited potent neutralizing activity against wild-type, Gamma, and Delta variants, with IC50 values under 4 μg/mL.
• The study identified promising scFvs with significant neutralizing capabilities.

Conclusions:

• Generated scFvs are potential candidates for developing advanced diagnostic tools for SARS-CoV-2.
• These scFvs can serve as valuable scaffolds for engineering next-generation monoclonal antibody therapeutics against SARS-CoV-2.
• The findings contribute to the ongoing efforts to control SARS-CoV-2 outbreaks through innovative antibody-based solutions.