IgG4 Antibody Hinge Modification for Stability
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Solution Overview
Problem
Current IgG4 antibodies face challenges such as propensity to form half-molecules, minimal effector function, and reduced stability, which affect their therapeutic efficacy and stability in vivo.
Innovation Solution
Modification of the IgG4 antibody by substituting cysteine residues in the heavy chain with other amino acids and altering the hinge region structure to enhance inter-chain disulfide bond arrangements, thereby improving thermal stability and reducing half-molecule formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If IgG4 antibodies are used as therapeutic agents, then effector function is minimized, but thermal stability and structural integrity deteriorate due to half-molecule formation
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of the IgG4 antibody, specifically substituting cysteine residues at positions 226 and/or 239 in the hinge region with serine or other non-cysteine amino acids. This changes the chemical parameters of the antibody structure, preventing the formation of intra-heavy chain disulfide bonds that lead to half-molecule formation, thereby improving thermal stability while maintaining therapeutic efficacy
Solution Approach 2:
The patent extracts or removes the problematic cysteine residues at positions 226 and/or 239 from the IgG4 heavy chain sequence. By taking out these specific cysteine amino acids and replacing them with serine or other non-cysteine residues, the patent eliminates the capacity for intra-heavy chain disulfide bond formation, thus preventing half-molecule formation and improving structural integrity
2Reliability
If IgG4 antibodies are used as therapeutic agents, then effector function is minimized, but structural integrity deteriorates due to formation of half-molecules
Solution Approach 1:
The patent changes the amino acid composition parameters of the IgG4 antibody by substituting cysteine residues with serine or other non-cysteine amino acids at specific positions in the hinge region. This parameter modification alters the bonding capabilities of the heavy chain, preventing intra-chain disulfide bond formation and half-molecule generation, thereby preserving structural integrity
Solution Approach 2:
The patent converts the potentially harmful cysteine residues that cause half-molecule formation into beneficial serine or non-cysteine residues. By this substitution, the harmful disulfide bond formation capability is eliminated, and the antibody gains improved structural stability and reduced aggregation, transforming a detrimental feature into a beneficial one
3Stability of the object's composition
If cysteine residues are substituted in the heavy chain, then half-molecule formation is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by making specific, targeted amino acid substitutions at defined positions (226 and/or 239) in the IgG4 heavy chain. Rather than comprehensive sequence modification, the patent changes only the critical cysteine residues, simplifying the manufacturing process while effectively preventing half-molecule formation
Solution Approach 2:
The patent applies local quality by making site-specific modifications only at the hinge region positions 226 and/or 239 where the problematic disulfide bond formation occurs. Rather than modifying the entire antibody sequence, the patent locally changes only the critical cysteine residues, maintaining ease of manufacture while achieving the desired stability improvement
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 modified IgG4 antibodies exhibit enhanced thermal stability and reduced half-molecule formation, maintaining therapeutic efficacy while minimizing effector function, thus improving their suitability as therapeutic agents.
Implementation Method 1
Each LC consists of a variable (VL) and constant domain (CO. Based on the HC, five main Ig classes are recognized... The basic structure of all immunoglobulin (Ig) molecules comprises two identical heavy chains (HCs) and two identical light chains (LCs) which are coupled by disulphide bonds
Data Source
AI summary
The present invention provides an antibody of the class IgG4 comprising at least one heavy chain which comprises a CH1 domain and a hinge region, wherein in each heavy chain: a. the inter-chain cysteine at position 127, numbered according to the Kabat numbering system, in the CH1 domain is substituted with another amino acid; and b. one or more of the amino acids positioned in the upper hinge region is substituted with cysteine.