Hepatitis C Detection Peptide with Mutated Epitopes
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Solution Overview
Problem
Current methods for detecting hepatitis C virus (HCV) infections face interference issues between anti-HCV antibodies and labeled antibodies, leading to false positive responses, especially in simultaneous detection assays for HCV capsid antigens and antibodies, due to shared epitopes, which complicates early and accurate detection during the serological window period.
Innovation Solution
A method involving the use of a peptide comprising an antigenic fragment derived from the truncated HCV capsid protein, specifically ranging from amino acids 1 to 44, with a point mutation at position 34, is employed to capture anti-capsid antibodies, avoiding epitope interference and enabling sensitive and specific detection of both capsid protein and antibodies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a capsid antigen with the same epitopes as those recognized by labeled anti-HCV capsid antibodies is deposited on the solid phase for detection of anti-HCV capsid antibodies, then simultaneous detection of capsid antigen and antibodies can be achieved, but binding of labeled antibodies to the solid phase occurs leading to false positive response
Solution Approach 1:
The patent applies local quality by creating two distinct versions of the capsid antigen with different epitope characteristics. The first antigen (native or wild-type) retains the original epitopes for antibody detection, while the second antigen (mutated version) has altered epitopes that prevent antibody binding but maintain structural integrity for antigen detection. This localized differentiation of epitope properties enables simultaneous detection without cross-interference.
Solution Approach 2:
The patent segments the capsid antigen function into two separate components: one component (native antigen) that interacts with antibodies for antibody detection, and another component (mutated antigen) that serves as a capture target for antigen detection without interfering with antibody binding. This functional segmentation eliminates the interference problem while maintaining both detection capabilities.
2Device complexity
If the same capsid epitopes are used for both capture and detection of anti-HCV antibodies, then the assay can be simplified, but interference between anti-HCV antibodies and labeled antibodies occurs
Solution Approach 1:
The patent applies parameter changes by modifying the epitope characteristics of the capture antigen through mutation. The capture antigen contains mutated epitopes that have altered binding properties - they no longer bind to anti-HCV antibodies with high affinity, thereby eliminating interference. This parameter modification (changing amino acid sequence) resolves the contradiction between assay simplicity and reliability.
3Loss of time
If early detection during the serological window period is achieved by detecting HCV antigen, then detection timing is improved, but interference from anti-HCV antibodies complicates the assay design
Solution Approach 1:
The patent segments the antigen detection system from the antibody detection system by using different antigen versions. The mutated antigen serves exclusively for early antigen detection during the serological window, while the native antigen is used for subsequent antibody detection. This segmentation enables early detection capability without the complexity of managing interfering reactions.
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
This approach allows for early and accurate detection of HCV infections with reduced false positives, facilitating monitoring of serological evolution post-seroconversion and improving the sensitivity of HCV detection assays.
Implementation Method 1
a peptide comprising an antigenic fragment derived from the truncated HCV capsid protein, specifically ranging from amino acids 1 to 44, with a point mutation at position 34, is employed to capture anti-capsid antibodies
Data Source
AI summary
The invention relates to a method of in-vitro detection of an infection with a hepatitis C virus (HCV) in a biological sample, comprising the simultaneous detection of the HCV capsid protein and of an antibody directed against said capsid protein, said method using, for capturing the anti-capsid antibodies, a peptide comprising an antigenic fragment derived from the truncated HCV capsid. The invention also relates to the peptide for capturing the anti-capsid antibodies and the kits comprising it.