Multiplexed Peptide Assay for Epitope-Resolved Coronavirus Detection
Solution Overview
Problem
Current diagnostic methods for coronavirus infections, including COVID-19 caused by SARS-CoV-2, lack high-resolution understanding of antibody responses, leading to incomplete detection of immune reactions and potential cross-reactivity with related viruses.
Innovation Solution
A synthetic biology approach using highly-multiplexed peptide-based serological assays, where libraries of peptide baits covalently coupled to DNA barcodes are synthesized to probe serum antibodies, providing a high-throughput sequencing read-out for accurate detection of SARS-CoV-2 exposure and identification of immunodominant antibody epitopes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full-length viral proteins or domains are used as antigenic baits in serological assays, then the assay can detect viral exposure with a range of accuracies, but the measurement provides only a single composite signal that lacks high-resolution understanding of antibody responses and may have cross-reactivity issues
Solution Approach 1:
The patent segments full-length viral proteins into multiple overlapping peptides (e.g., 15-mer peptides with 10-mer overlaps). This segmentation allows the assay to resolve antibody responses at the epitope level rather than providing a single composite signal, thereby preventing information loss about specific antigen recognition patterns while maintaining detection accuracy
Solution Approach 2:
The patent transitions from one-dimensional full-length protein detection to a multi-dimensional peptide array approach where antibodies are tested against numerous individual peptide sequences. This dimensional expansion enables simultaneous measurement of multiple epitope-specific responses, preserving information about which specific viral regions are recognized while maintaining overall detection sensitivity
2Reliability
If peptide-based serological assays are used to achieve epitope-resolved views of antibody responses, then cross-reactivity can be identified and specificity improved, but the device complexity and manufacturing complexity increase
Solution Approach 1:
The patent creates a universal peptide array platform that can detect antibodies against multiple coronavirus types (SARS-CoV-2, SARS-CoV, MERS-CoV, and endemic coronaviruses) using a single standardized assay format. This multi-functional approach allows the same complex device to perform differentiated diagnosis across various viruses, justifying the complexity through enhanced reliability and cross-reactivity detection capabilities
Solution Approach 2:
The patent performs preliminary computational design and selection of peptide sequences before assay execution, using bioinformatics to identify immunodominant epitopes and design overlapping peptide libraries. This preliminary action reduces the complexity of the actual assay by pre-optimizing the peptide set to focus on the most diagnostically relevant regions, thereby managing device complexity while maintaining high specificity
3Measurement precision
If highly-multiplexed peptide libraries with DNA barcodes are synthesized and used for probing serum antibodies, then high-throughput sequencing read-out provides accurate detection of SARS-CoV-2 exposure and identification of immunodominant epitopes, but the manufacturing precision and ease of manufacture are challenged
Solution Approach 1:
The patent uses DNA barcodes as information copies that link each peptide sequence to its identity. Instead of manually tracking or characterizing each peptide, the system creates a replicable DNA record of the peptide library composition, enabling high-throughput sequencing to accurately read out which peptides bound antibodies. This copying approach maintains manufacturing precision by providing a verifiable record of the peptide sequences without requiring complex manual verification
Solution Approach 2:
The patent employs in vitro transcription and translation systems that self-assemble the peptide-DNA barcode conjugates from synthesized DNA templates. The biological machinery performs the complex synthesis and coupling automatically, reducing the need for manual intervention and minimizing errors in peptide-DNA association. This self-service approach maintains manufacturing precision through the inherent accuracy of enzymatic processes while simplifying the overall manufacturing workflow
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method accurately detects SARS-CoV-2 exposure and reveals multiple immunodominant antibody epitopes, including those that cross-react between SARS-CoV-2 and endemic human coronaviruses, enhancing the specificity and sensitivity of diagnostic assays.
Implementation Method 1
contacting the biological sample with a peptide comprising an amino acid sequence having at least 85% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 1-4, 275-412, and 421-423; and detecting antigen-antibody complexes formed
Data Source
AI summary
The present disclosure includes a multiplexed peptide assay to generate an epitope-resolved view of antibody reactivity across all human coronaviruses (CoVs). PepSeq accurately classifies SARS-CoV-2 exposure status and reveals epitopes across the Spike and Nucleocapsid proteins. Two of these represent recurrent reactivities to conserved, functionally-important sites in the S2 subunit of Spike, regions that we show are also targeted for the endemic CoVs in pre-pandemic controls. At one of these sites, we demonstrate that the SARS-CoV-2 response strongly and recurrently cross-reacts with the endemic virus hCoV-OC43. The disclosed epitope-resolved analysis reveals new CoV targets for the development of diagnostics, vaccines and therapeutics, including a site that may have broad neutralizing potential.