Mutant Streptavidin and Modified Biotin for Reduced Immunogenicity
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Solution Overview
Problem
The high immunogenicity of chicken-derived avidin and microorganism-derived streptavidin leads to the generation of anti-avidin/streptavidin antibodies in humans, causing background issues in diagnostics and reducing the effectiveness of medicinal treatments using streptavidin-based pretargeting methods.
Innovation Solution
A mutant streptavidin with reduced affinity for natural biotin and a modified biotin with high affinity for the mutant streptavidin are developed, allowing for their use in diagnostic and therapeutic applications with reduced immunogenicity and improved specificity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If chicken-derived avidin or microorganism-derived streptavidin is used for pretargeting, then high binding ability is achieved, but high immunogenicity causes anti-avidin/streptavidin antibody generation
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of streptavidin to create mutant forms (e.g., LISA314, LISA314-V21) with altered immunogenic properties while preserving biotin binding capability. This involves changing specific amino acid residues to reduce immune recognition while maintaining the core functional parameters of the protein.
Solution Approach 2:
The patent introduces a modified biotin compound as an intermediary that bridges the mutant streptavidin and the target antigen. The modified biotin has reduced affinity for natural streptavidin but high affinity for the mutant form, thereby mediating the interaction while avoiding the immunogenicity problems of wild-type streptavidin.
2Object-affected harmful factors
If low immunogenic streptavidin with affinity for natural biotin is used, then reduced immunogenicity is achieved, but high background is caused in diagnostics
Solution Approach 1:
The patent modifies the biotin molecule itself (creating compounds of formula (1) and (2)) to change its binding parameters. The modified biotin has selectively altered affinity - reduced binding to natural streptavidin and endogenous biotin sites, but maintained or enhanced binding to the mutant streptavidin, thereby reducing background while preserving signal.
Solution Approach 2:
The patent extracts the essential binding function from the natural biotin-streptavidin system and separates it into two independent components: mutant streptavidin (with reduced immunogenicity) and modified biotin (with selective binding). This extraction allows optimization of each component independently to overcome the background noise problem.
3Measurement precision
If mutant streptavidin with reduced affinity for natural biotin is developed, then specificity is improved, but affinity for modified biotin must be maintained
Solution Approach 1:
The patent systematically changes the parameters of both streptavidin (amino acid mutations) and biotin (molecular structure modification) to achieve the desired affinity profile. The mutant streptavidin variants (LISA314, LISA314-V21) have specific amino acid changes that reduce natural biotin affinity while the modified biotin compounds (formula (1) and (2)) have structural modifications that maintain binding to the mutant form.
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 combination of the mutant streptavidin and modified biotin enables effective diagnostic and therapeutic methods with reduced immunogenicity and background noise, enhancing the specificity and efficacy of streptavidin-based treatments.
Implementation Method 1
a modified biotin having an affinity for the aforementioned mutant streptavidin
Data Source
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AI summary
It is an object of the present invention to provide a mutant streptavidin with a reduced affinity for natural biotin, and also to provide a modified biotin having a high affinity for the mutant streptavidin with a reduced affinity for natural biotin. According to the present invention, there is provided a reagent kit for use in treatments or diagnoses, which comprises: (a) a mutant streptavidin with a reduced affinity for natural biotin or biocytin; and a modified biotin having a high affinity for the above-described mutant streptavidin.