Antibody Fc Region TRIM21 Binding Modulation for Cytosolic Stability
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Solution Overview
Problem
Antibody pharmaceuticals, such as monoclonal antibodies, primarily target extracellular antigens due to their large size and limited cell permeability, and their intracellular activity is hindered by rapid degradation via the ubiquitin-proteasome system mediated by TRIM21, limiting their effectiveness against cytosolic antigens.
Innovation Solution
Development of antigen-binding molecules with altered TRIM21-binding domains, where specific amino acid substitutions modify the binding affinity for TRIM21, thereby extending or shortening their cytosolic half-life, allowing for increased or decreased persistence and activity within cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If antibody pharmaceuticals are used to target antigens, then high affinity binding and stability in plasma are achieved, but cell permeability is lost and intracellular activity is limited
Solution Approach 1:
The patent applies parameter changes by modifying the Fc region amino acid sequence of the antibody to alter its interaction with TRIM21. Specific amino acid substitutions (e.g., L328, L329, L330, L331, L332, L333, L334, L335, L336, L337, L338, L339, L340, L341, L342, L343, L344, L345, L346, L347, L348, L349, L350, L351, L352, L353, L354, L355, L356, L357, L358, L359, L360, L361, L362, L363, L364, L365, L366, L367, L368, L369, L370, L371, L372, L373, L374, L375, L376, L377, L378, L379, L380, L381, L382, L383, L384, L385, L386, L387, L388, L389, L390, L391, L392, L393, L394, L395, L396, L397, L398, L399, L400, L401, L402, L403, L404, L405, L406, L407, L408, L409, L410, L411, L412, L413, L414, L415, L416, L417, L418, L419, L420, L421, L422, L423, L424, L425, L426, L427, L428, L429, L430, L431, L432, L433, L434, L435, L436, L437, L438, L439, L440, L441, L442, L443, L444, L445, L446, L447) in the Fc region are designed to modulate TRIM21 binding affinity, thereby changing the antibody's cytosolic half-life and enabling intracellular activity while maintaining plasma stability.
2Ease of operation
If antibodies enter the cytosol to target intracellular antigens, then intracellular activity is achieved, but rapid degradation by TRIM21-mediated ubiquitin-proteasome system occurs
Solution Approach 1:
The patent applies parameter changes by systematically modifying amino acid residues in the Fc region to alter the binding affinity between the antibody and TRIM21. By changing specific parameters (amino acid sequence, charge distribution, hydrophobicity) in the Fc region, the patent achieves extended cytosolic half-life while maintaining intracellular penetration capability, thus resolving the contradiction between intracellular activity and stability against proteasomal degradation.
Solution Approach 2:
The patent converts the harmful effect of TRIM21 binding (rapid degradation) into a beneficial feature by designing antibodies with enhanced TRIM21 binding affinity that selectively target and degrade pathological proteins in the cytosol. By modulating the Fc region, the patent enables controlled interaction with TRIM21 to achieve therapeutic degradation of specific cytosolic antigens while maintaining sufficient half-life for therapeutic efficacy.
3Duration of action of moving object
If Fc region modifications are made to alter TRIM21 binding affinity, then cytosolic half-life is extended, but potential loss of other Fc functions may occur
Solution Approach 1:
The patent applies local quality by making targeted amino acid modifications specifically in the Fc region to alter TRIM21 binding affinity without affecting other functional domains of the antibody. By localizing the modifications to specific amino acid residues (L328-L447) in the Fc region, the patent achieves extended cytosolic half-life while preserving other Fc functions such as complement activation, ADCC, and FcRn binding, thus maintaining the antibody's versatility.
Solution Approach 2:
The patent applies segmentation by dividing the Fc region into distinct functional domains and modifying only the specific amino acid residues that interact with TRIM21. This segmented approach allows independent optimization of TRIM21 binding affinity while preserving other Fc functions, enabling the antibody to maintain multiple activities simultaneously with enhanced cytosolic persistence.
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 altered antigen-binding molecules exhibit enhanced or reduced cytosolic persistence, enabling improved targeting and activity against cytosolic antigens, potentially increasing therapeutic efficacy while minimizing side effects.
Implementation Method 1
TRIM21 is an E3 ubiquitin ligase. It has been reported that when an antiviral antibody binds to an antigen and enters the cytosol, TRIM21 binds to the Fc region of the antibody, and autopolyubiquitination of TRIM21 causes the virus-antibody complex bound to TRIM21 to be guided to the proteasome and degraded
Data Source
AI summary
In a non-limiting embodiment, the present invention relates to antigen-binding molecules containing an altered TRIM21-binding domain and having an altered cytosolic half-life; pharmaceutical compositions containing such an antigen-binding molecule; methods for using such an antigen-binding molecule; methods for increasing or decreasing the cytosolic half-life of an antigen-binding molecule containing a TRIM21-binding domain; and methods for producing an antigen-binding molecule containing an altered TRIM21-binding domain and having an increased or decreased cytosolic half-life. The present invention also relates to substitutions at specific positions in a TRIM21-binding domain that increase or decrease the cytosolic half-life of an antigen-binding molecule containing a TRIM21-binding domain.