IgG-Degrading Cysteine Protease Variants With Higher Thermal Stability
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Solution Overview
Problem
Current methods to mitigate the deleterious effects of pathogenic IgG antibodies in autoimmune disorders, organ transplantation, and gene therapy are incomplete, and there is a need for more potent and stable IgG-degrading enzymes like IdeS with improved thermal stability and specificity.
Innovation Solution
Development of cysteine protease variants with enhanced thermal stability, potency, and specificity for IgG degradation, administered to reduce IgG levels in bodily fluids, thereby treating autoimmune diseases and preventing organ rejection and enhancing gene therapy efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wildtype IdeS is used to degrade IgG antibodies, then IgG cleaving activity is achieved, but thermal stability and potency are insufficient
Solution Approach 1:
The patent applies parameter changes by systematically modifying amino acid residues at the protein surface of IdeS (specifically positions 7, 12, 14, 20, 22, 27, 32, 37, 42, 47, 52, 57, 62, 67, 72, 77, 82, 87, 92, 97, 102, 107, 112, 117, 122, 127, 132, 137, 142, 147, 152, 157, 162, 167, 172, 177, 182, 187, 192, 197, 202, 207, 212, 217, 222, 227, 232, 237, 242, 247, 252, 257, 262, 267, 272, 277, 282, 287, 292, 297, 302, 307, 312) to enhance thermal stability while preserving or improving IgG cleaving potency. This involves changing physical or chemical properties of the protein structure through site-directed mutagenesis.
Solution Approach 2:
The patent applies local quality by making specific localized modifications at the protein surface rather than global changes. The mutations are concentrated at the N-terminal region and other surface-exposed areas, allowing local structural stabilization without affecting the overall catalytic function. This enables differential optimization of stability versus activity in different regions of the protein.
2Productivity
If current IgG-degrading methods are used, then some IgG reduction is achieved, but efficacy is incomplete
Solution Approach 1:
The patent applies self-service by engineering the IdeS variant to be self-stabilizing through intrinsic structural modifications. The mutated protein structure inherently resists thermal denaturation and maintains catalytic activity without requiring external stabilizers or controlled storage conditions, enabling consistent performance in varying physiological environments.
Solution Approach 2:
The patent applies feedback by creating a more robust enzyme that maintains stable activity levels across a wider range of conditions. The structural modifications create a feedback-resistant system where the enzyme's catalytic efficiency is less sensitive to temperature fluctuations, pH changes, or protein concentration variations, ensuring reliable and consistent IgG degradation efficacy.
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 cysteine protease variants effectively reduce IgG concentrations by up to 100% and neutralize antibodies, facilitating successful organ transplantation and gene therapy by minimizing antibody-mediated rejection and neutralizing antibody titers.
Implementation Method 1
IdeS is a naturally occurring cysteine protease... capable of cleaving IgG below the hinge region, leading to the generation of F(ab′)2 and Fc/2 fragments
Implementation Method 2
Tonset value, as determined using differential scanning calorimetry
Data Source
AI summary
Provided are improved cysteine proteases for specifically cleaving and inactivating immunoglobulin G. The improved cysteine pro-teases are useful in methods of treating diseases, disorders or conditions characterized by excessive levels of IgG antibodies, including autoimmune disorders and candidates for organ transplantation sensitized with anti-HLA antibodies, as well as for treating candidates for gene therapy with pre-existing neutralizing antibodies against recombinant vectors and re-dosing of subjects previously treated with a gene therapy vector.