Dimeric Antibody Manufacturing with Single-Heavy-Chain Cysteine Linking
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Solution Overview
Problem
Existing methods for producing disulfide-linked dimeric antibodies result in heterogeneous populations due to chemical crosslinking or engineering multiple cysteines, leading to constrained conformations and unwanted crosslinking, which has hindered their clinical application.
Innovation Solution
Introduce a cysteine mutation into a single heavy chain of an IgG antibody, combine it with another IgG under mild reducing conditions to dissociate and reform as chimeric antibodies, then oxidize them to form disulfide-linked dimers, ensuring only a single cysteine is involved in the bond.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If chemical crosslinking is used to produce dimeric antibodies, then dimeric antibodies can be formed, but heterogeneous populations with varying pharmacological effects are created
Solution Approach 1:
The patent introduces a cysteine mutation at a specific location (e.g., hinge region) of the antibody heavy chain, creating a localized functional site that enables controlled disulfide bond formation. This localized modification ensures that crosslinking occurs at a predetermined position, producing homogeneous dimers rather than heterogeneous populations from random chemical crosslinking.
Solution Approach 2:
The patent changes the chemical parameter of the antibody by introducing a cysteine residue that can form disulfide bonds. This parameter change enables controlled covalent linking between antibodies through oxidation, transitioning from non-covalent or random chemical crosslinking to controlled disulfide bond formation, thereby achieving homogeneity.
2Ease of manufacture
If multiple cysteines are engineered into antibodies for crosslinking, then dimeric antibodies can be formed, but unwanted crosslinking and constrained conformations occur
Solution Approach 1:
The patent extracts or removes extraneous cysteine residues from the antibody sequence, retaining only the specifically engineered cysteine at the desired crosslinking location. This elimination of unnecessary cysteines prevents unwanted disulfide bonds and conformational constraints while maintaining the desired dimeric structure.
Solution Approach 2:
The patent performs preliminary action by pre-positioning the cysteine residue at the exact location where disulfide bond formation is desired, before the crosslinking process occurs. This preliminary placement ensures that when oxidation is applied, disulfide bonds form only at the intended sites, preventing unwanted crosslinking and preserving proper antibody conformation.
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
This method produces homogeneous disulfide-linked dimeric antibodies, reducing unwanted crosslinking and enhancing their therapeutic potential by allowing diverse conformations and reducing heterogeneity.
Implementation Method 1
the first IgG antibody is then combined with a second IgG antibody under mild reducing conditions to reduce disulfide bonds that crosslink the two different heavy chains of the IgGs
Implementation Method 2
The chimeric antibodies are then subjected to mild oxidizing conditions to form disulfide-linked dimers of the chimeric antibodies
Data Source
AI summary
This disclosure relates to dimeric immunotherapeutics that comprise two IgGs that are crosslinked with a disulfide bond. The two IgGs may be chimeras of two different heavy chains, in which one heavy chain includes a cysteine mutation that forms the disulfide bond, and the other heavy chain lacks the cysteine mutation. The presence of a cysteine mutation in only one of the heavy chains of an IgG avoids two disulfide bonds between the two IgGs, which increases the accessible orientations between the two crosslinked IgGs, and also avoids the formation of trimers and higher-order oligomers.