HEV Antigen Polypeptide Selection for Sensitive Antibody Detection
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Solution Overview
Problem
Conventional methods for detecting hepatitis E virus (HEV) infections suffer from insufficient sensitivity, particularly in detecting anti-HEV antibodies, leading to false negatives in many samples.
Innovation Solution
A method involving the use of a dimeric antigen polypeptide derived from the E2s domain of the HEV capsid protein, specifically amino acids 28 to 175, with a length of 200 residues or less, to enhance the detection of anti-HEV antibodies, particularly IgM, through a sandwich ELISA-like assay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional antigen polypeptides (amino acids 111-660 of ORF2 genotype 4 or amino acids 394-606 of ORF2 genotype 1) are used for detection, then the detection method is established and can be implemented, but the detection sensitivity is insufficient leading to false negatives in many samples
Solution Approach 1:
The patent changes the critical parameters of the antigen polypeptide: selecting a different genomic region (amino acids 28-175 of E2s domain from ORF2) and optimizing the length to 200 residues or less. This parameter optimization significantly improves detection sensitivity and reduces false negatives compared to conventional antigen polypeptides.
Solution Approach 2:
The patent extracts only the essential immunogenic portion (amino acids 28-175 of the E2s domain) from the full ORF2 sequence. By taking out just this critical segment and limiting it to 200 residues or less, the patent achieves high detection sensitivity while eliminating non-essential regions that may contribute to false negatives.
2Measurement precision
If the antigen polypeptide length is reduced to 200 residues or less, then the detection sensitivity is improved, but the structural complexity of the antigen design increases
Solution Approach 1:
The patent segments the full ORF2 sequence (660 amino acids) into distinct functional domains, identifying the E2s domain (amino acids 28-175) as the critical immunogenic region. By segmenting and selecting only this essential portion, the patent achieves simplified 200-residue or less polypeptides with optimized detection sensitivity.
Solution Approach 2:
The patent applies local quality by concentrating the immunogenic activity into a specific local region (amino acids 28-175 of the E2s domain) rather than using the entire ORF2 sequence. This localized approach ensures high detection sensitivity with a compact 200-residue or less polypeptide structure.
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 achieves higher sensitivity in detecting HEV infections, enabling the detection of anti-HEV antibodies in samples that were previously undetectable by conventional kits, thereby improving diagnostic accuracy.
Implementation Method 1
a detection step of detecting an anti-hepatitis E virus antibody in a sample by using, as an antigen polypeptide, a dimer consisting of any one polypeptide selected from the group consisting of (3a) to (3c), and any one polypeptide selected from the group consisting of (1a) to (1c), (2a) to (2c), and (4a) to (4c)
Data Source
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AI summary
The present invention is a method for detecting hepatitis E virus infection, comprising a detection step of detecting anti-hepatitis E virus antibodies in a sample by using, as an antigen polypeptide, at least one polypeptide selected from the group consisting of the following (a) to (c): (a) a polypeptide consisting of an amino acid sequence which includes amino acids located at position 28 to 175 in the amino acid sequence set forth in any one of SEQ ID NOs: 1 to 4 and which has a full length of 200 residues or less that are contained in the amino acid sequence set forth in the sequence number; (b) a polypeptide consisting of an amino acid sequence in which one or more amino acids are substituted, deleted, inserted, and/or added in the amino acid sequence which includes amino acids located at position 28 to 175 in the amino acid sequence set forth in any one of SEQ ID NOs: 1 to 4 and which has a full length of 200 residues or less that are contained in the amino acid sequence set forth in the sequence number; and (c) a polypeptide consisting of an amino acid sequence having 80% or more homology with the amino acid sequence which contains amino acids located at position 28 to 175 in the amino acid sequence set forth in any one of SEQ ID NOs: 1 to 4 and which has a full length of 200 residues or less that are contained in the amino acid sequence set forth in the sequence number.