Mutant VHH Antibody Affinity Carrier for Modified IgG Purification
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Solution Overview
Problem
Current affinity chromatography methods for purifying modified antibodies, such as those used in antibody drugs, face challenges in efficiently isolating and eluting immunoglobulins due to limitations in ligand specificity and binding capacity, particularly for antibodies like trastuzumab.
Innovation Solution
Development of an affinity carrier utilizing a mutant VHH antibody with specific amino acid mutations, such as histidine and arginine substitutions, immobilized on a solid phase carrier, which recognizes epitopes in the Fab region of immunoglobulins, enabling improved binding and elution capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Protein A is used as a ligand for affinity chromatography of IgG subclass antibodies, then the purification process is established and reliable, but the binding capacity and elution efficiency are insufficient for modified antibodies such as partial antibodies, antibody-drug conjugates, and bispecific antibodies
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of the VHH antibody to create mutant versions with altered binding properties. Specifically, mutations in the CDR regions (particularly CDR3) and framework regions change the ligand's affinity and specificity characteristics, enabling effective binding to modified antibodies that Protein A cannot efficiently purify
Solution Approach 2:
The patent creates a composite affinity carrier system by combining the mutant VHH antibody ligand with a solid support matrix. This composite structure integrates the specific binding capability of the engineered VHH protein with the physical properties of the solid phase, achieving both high specificity for modified antibodies and effective purification performance
2Ease of manufacture
If conventional VHH antibody is used as a ligand, then the structure is simple and easy to produce, but the binding affinity and elution behavior for immunoglobulins are insufficient
Solution Approach 1:
The patent systematically modifies the VHH antibody sequence by introducing specific amino acid substitutions, deletions, or additions in key regions (CDR3, framework regions). These parameter changes in the primary structure directly improve the tertiary structure and binding interface, enhancing both binding affinity and elution characteristics while preserving the overall simplicity of the VHH domain architecture
Solution Approach 2:
The patent applies local quality changes by making targeted mutations in specific regions of the VHH antibody (particularly in CDR3 and framework regions) rather than modifying the entire structure. This localized optimization maintains the general simplicity and ease of production of VHH antibodies while concentrating improvements in binding performance at the critical antigen-binding sites
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 affinity carrier demonstrates enhanced binding and elution behavior for immunoglobulins, increasing production efficiency and specificity for modified antibodies like trastuzumab, compared to traditional Protein A-based methods.
Implementation Method 1
an immunoglobulin-binding protein bound to the solid phase carrier, wherein the immunoglobulin-binding protein comprises a mutant VHH antibody or a fragment of the mutant VHH antibody that recognizes an epitope in at least one region selected from the group consisting of amino acids 127 to 184 of SEQ ID NO: 22 and amino acids 13 to 210 of SEQ ID NO: 23
Data Source
AI summary
Provision of an affinity carrier using a mutant VHH antibody. An affinity carrier comprising: a solid phase carrier; and an immunoglobulin-binding protein bound to the solid phase carrier; wherein the immunoglobulin-binding protein comprises a mutant VHH antibody or a fragment of the mutant VHH antibody that recognizes an epitope in at least one region selected from the group consisting of amino acids 127 to 184 of SEQ ID NO: 22 and amino acids 13 to 210 of SEQ ID NO: 23.