Synthetic proteins for COVID-19 diagnostics

Area of Science:

• Immunology
• Virology
• Biochemistry

Background:

• Urgent need for cost-effective, rapid antigen-based assays for SARS-CoV-2 detection and vaccine efficacy.
• Existing methods may not adequately address evolving SARS-CoV-2 variants.
• Development of specific diagnostics is crucial for managing the pandemic.

Purpose of the Study:

• To identify and characterize a novel synthetic antigen for SARS-CoV-2 diagnostics.
• To evaluate the antigen's binding properties with antibodies from COVID-19 patients.
• To explore the potential of synthetic antigens for detecting infection and assessing vaccine response.

Main Methods:

• Identification of a synthetic protein (JS7) from a variable region of the SARS-CoV-2 receptor binding domain (RBD).
• Testing antibody binding to JS7 and recombinant RBD in sera from PCR-verified COVID-19 patients.
• Assessing antibodies that disrupt ACE2 receptor-RBD binding.
• Synthesizing JS7 variants (e.g., E484K, N501Y) using automated methods.

Main Results:

• JS7 binds antibodies in sera from COVID-19 patients with varying disease severity.
• Antibody binding to JS7 and disruption of ACE2-RBD interaction correlate with disease severity.
• Binding to JS7 is inhibited by peptides from the RBD-ACE2 interface.
• JS7 variants can be rapidly synthesized in large quantities.

Conclusions:

• JS7 and related synthetic antigens offer a foundation for developing specific SARS-CoV-2 diagnostics.
• These antigens can aid in detecting infections and evaluating vaccine efficacy.
• The synthetic approach allows for rapid adaptation to new SARS-CoV-2 variants.