Native Microfluidic CE-MS Antibody Charge Heterogeneity Analysis
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Solution Overview
Problem
Current methods for characterizing therapeutic antibodies, such as monoclonal antibodies, face challenges in effectively monitoring post-translational modifications (PTMs) and detecting variants, which are crucial for ensuring product quality and safety due to the heterogeneity and complexity of these biomolecules.
Innovation Solution
A method combining native microfluidic capillary electrophoresis with mass spectrometry is developed to separate, identify, and quantify antibody fragments, allowing for the detection and discrimination of PTMs, including deamidation, oxidation, and glycosylation, by digesting samples with proteases like IdeS and separating fragments by molecular weight and charge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to characterize therapeutic antibodies, then the analysis is simpler and faster, but the detection precision and ability to distinguish variants is insufficient
Solution Approach 1:
The patent combines capillary electrophoresis (CE) with mass spectrometry (MS) into an integrated CE-MS system. The CE component separates antibody fragments based on charge-to-mass ratio, while the MS component provides precise mass measurement for identification of PTMs. This merging of two analytical techniques enables simultaneous separation and precise detection, resolving the contradiction between detection precision and method complexity.
Solution Approach 2:
The patent employs proteolytic digestion (e.g., with IdeS protease) to segment intact antibodies into smaller fragments (F(ab')2 and Fc fragments). This segmentation reduces the complexity of analyzing intact heterogeneous antibodies while maintaining the ability to detect PTMs. The fragments are then separated by CE and analyzed by MS, enabling precise detection of variants without overwhelming complexity from analyzing full-length heterogeneous molecules.
2Measurement precision
If conventional characterization methods are used, then the analysis is less complex, but the ability to detect low-abundance species and impurities is limited
Solution Approach 1:
The integration of CE's high-resolution separation capability with MS's sensitive detection capability enables detection of low-abundance species. CE separates charge variants and fragments with high resolution, concentrating them in distinct zones, while MS detects these separated species with high sensitivity, including low-abundance PTM variants that would be masked in conventional bulk analysis methods.
Solution Approach 2:
The patent replaces conventional bulk detection methods (such as UV detection in HPLC) with mass spectrometric detection. MS provides superior sensitivity and specificity for detecting low-abundance species by measuring mass-to-charge ratios, enabling identification of trace PTM variants, oxidized forms, and impurities that conventional methods cannot detect at comparable sensitivity levels.
3Measurement precision
If comprehensive PTM analysis is performed, then product quality characterization is improved, but the analysis time and resource consumption increase
Solution Approach 1:
By digesting antibodies with proteases to generate standardized fragments, the method enables parallel analysis of multiple PTM types across different protein regions. The CE-MS system analyzes all fragments simultaneously in a single run, providing comprehensive PTM characterization (deamidation, oxidation, glycosylation, etc.) without requiring multiple separate experiments, thus reducing total analysis time while maintaining comprehensive characterization.
Solution Approach 2:
The CE-MS integration allows simultaneous separation and detection of multiple PTM variants in a single analytical run. The CE dimension separates fragments by charge-to-mass ratio, resolving overlapping PTM variants, while the MS dimension provides precise mass measurement for identification. This combined approach comprehensively characterizes multiple PTM types concurrently, reducing analysis time compared to sequential use of separate methods for each PTM type.
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 approach provides high-resolution and sensitive analysis of antibody variants, enabling the detection of low-abundance species and impurities, improving the characterization of therapeutic antibodies and ensuring consistent product quality and safety.
Implementation Method 1
separating antibody fragments by molecular weight and/or charge in one or more capillaries using capillary electrophoresis
Implementation Method 2
determining the mass of the eluted antibody fragments by mass spec analysis, thereby detecting and/or discriminating between post-translational modification variants
Data Source
AI summary
The present invention pertains to methods for characterizing proteins in a sample using native capillary electrophoresis-mass spectrometry. The present invention pertains to methods for detecting and/or discriminating between post-translational modification variants of an antibody of interest in a sample, detecting and/or discriminating between antibodies in an antibody mixture, and characterizing monospecific antibody side products in a bispecific antibody sample.