ORF2i-Specific Antibodies for Hepatitis E Virus Diagnostic Specificity
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Solution Overview
Problem
Current diagnostic methods for hepatitis E virus (HEV) infection rely on detecting anti-HEV antibodies and viral RNA, but they lack specificity for distinguishing between infectious and non-infectious forms of the ORF2 capsid protein, which can lead to false positives and inadequate diagnosis.
Innovation Solution
Development of antibodies specifically binding to the ORF2i protein of HEV, which are not glycosylated and associated with infectious particles, allowing for precise detection of infectious HEV particles without cross-reactivity with glycosylated forms ORF2g and ORF2c.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If antibodies are developed to detect all ORF2 protein forms (ORF2i, ORF2g, ORF2c), then the diagnostic coverage is improved, but the specificity for detecting infectious particles deteriorates due to cross-reactivity with non-infectious glycosylated forms
Solution Approach 1:
The invention segments the diagnostic approach by targeting a specific epitope (amino acids 542-555) within the ORF2 protein that is exclusively present in the non-glycosylated ORF2i form. This segmentation allows the antibody to distinguish between infectious (ORF2i) and non-infectious (ORF2g, ORF2c) forms, resolving the contradiction between broad coverage and high specificity.
Solution Approach 2:
The invention applies local quality by focusing on a specific region (epitope at amino acids 542-555) of the ORF2 protein that differs between glycosylated and non-glycosylated forms. The antibody is designed to recognize this local characteristic, enabling differentiation of protein forms based on their glycosylation status without requiring detection of the entire protein structure.
2Reliability
If diagnostic assays detect all ORF2 protein forms, then the sensitivity for HEV infection is improved, but the reliability of diagnosing infectious particles deteriorates due to false positives from non-infectious forms
Solution Approach 1:
The invention extracts the specific epitope sequence (amino acids 542-555) from the full ORF2 protein and uses it as the target for antibody recognition. This extraction approach allows the diagnostic assay to specifically detect only the non-glycosylated ORF2i form associated with infectious particles, eliminating false positives from glycosylated forms while maintaining high sensitivity.
Solution Approach 2:
The invention changes the detection parameter from recognizing the entire ORF2 protein structure to recognizing a specific amino acid sequence (542-555) that is differentially present in glycosylated versus non-glycosylated forms. This parameter change enables the assay to distinguish between infectious and non-infectious particles, improving reliability by eliminating false positives.
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 antibodies provide a specific and effective means to diagnose HEV infection by selectively binding to the ORF2i protein, enhancing diagnostic accuracy and distinguishing infectious particles from non-infectious forms.
Implementation Method 1
an antibody which binds to the ORF2i protein of hepatitis E virus and wherein said antibody does not bind to the ORF2g protein nor to the ORF2c of hepatitis E virus
Data Source
Figure 1A~1C
Figure 1D~1E
AI summary
Hepatitis E virus (HEV) is annually responsible for 20 million infections with 3.4 million symptomatic cases and 70,000 deaths mainly occurring in less developed regions of the world. HEV is a non-enveloped virus containing a linear, single-stranded, positive-sense RNA genome that contains three open reading frames (ORFs), namely, ORF1, ORF2 and ORF3. ORF2 encodes the ORF2 viral capsid protein, which is involved in particle assembly, binding to host cells and eliciting neutralizing antibodies. Recently, 3 different forms of the ORF2 capsid protein were identified: infectious/intracellular ORF2 (ORF2i), glycosylated ORF2 (ORF2g), and cleaved ORF2 (ORF2c). The ORF2i protein, for which the precise sequence has been identified, is the form that is associated with infectious particles and thus antibodies having specificity for the ORF2i protein would be suitable for the diagnosis of HEV. The present fulfills this need by providing an antibody which binds to the ORF2i protein of hepatitis E virus and wherein said antibody does not bind to the ORF2g protein nor to the ORF2c of hepatitis E virus, and wherein the epitope of said antibody comprises at least one amino acid residue from amino acid residues 542 to 555 of SEQ ID NO: 1.