Stabilized Human IgG2 and IgG3 Antibodies
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Solution Overview
Problem
IgG2 and IgG3 antibodies are unstable at low pH, leading to aggregate formation during production, which can cause side effects such as infusion reactions and complement activation, making it challenging to develop them as drugs.
Innovation Solution
Modifying the partial amino acid structures of the heavy chain constant regions of IgG2 and IgG3 antibodies, specifically substituting certain amino acids like Y for F at the 300th position, L for V at the 309th position, or A for T at the 339th position, and using CH2 and CH3 domains from IgG1 heavy chains to improve stability and reduce aggregate formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If IgG2 and IgG3 antibodies are used as drugs, then novel activity can be expected, but they form aggregates at low pH causing side effects
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence parameters of the heavy chain constant regions. Specific substitutions are made at defined positions: IgG2 antibodies receive substitutions at positions 300 (Y→F), 309 (L→V), and/or 339 (A→T), while IgG3 antibodies receive substitutions at positions 392 (K→N) and 397 (V→M). These parameter changes in the amino acid sequence stabilize the antibody structure at low pH and prevent aggregate formation, resolving the contradiction between antibody stability and harmful aggregate formation.
2Ease of manufacture
If low pH buffer solution is used to elute antibodies from Protein A, then antibody purification is achieved, but aggregate formation increases
Solution Approach 1:
The patent converts the harmful effect of low pH conditions into a beneficial process. The modified antibody constant regions are specifically designed to withstand low pH environments. By incorporating the amino acid substitutions described above, the antibodies can undergo low pH elution from Protein A columns without forming aggregates, thus converting a potentially harmful condition into a useful purification step.
3Adaptability or versatility
If IgG2 and IgG3 subclasses are developed as drugs, then diverse functions can be achieved, but production techniques remain uncertain
Solution Approach 1:
The patent addresses production technique uncertainty by establishing specific amino acid substitution parameters that ensure stability during manufacturing and purification. By defining precise substitution sites and residues for both IgG2 and IgG3 subclasses, the invention provides clear production guidelines that can be consistently applied across different manufacturing processes, thereby resolving the uncertainty in production techniques while maintaining functional diversity.
Data Source
AI summary
It is intended to provide highly stable variants of human antibody IgG2 and IgG3 subclasses. The present invention provides an IgG heavy chain comprising the constant region of a human IgG2 heavy chain having at least a substitution of Y for F at the 300th position, L for V at the 309th position, or A for T at the 339th position designated by the EU index of Kabat et al. and an IgG heavy chain comprising the constant region of a human IgG3 heavy chain having at least a substitution of K for N at the 392nd position or V for M at the 397th position designated by the EU index of Kabat et al. The present invention also provides monoclonal antibodies comprising these heavy chains.