Antibody Quantitation via IdeS Digestion and Native SCX-MS
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Solution Overview
Problem
Current methods for characterizing and quantifying therapeutic peptides or proteins, such as antibodies, face challenges due to post-translational modifications, protein degradation, and chemical modifications during production and purification, which affect their safety, efficacy, and shelf life, especially in complex matrices like serum, requiring high-throughput and high-sensitivity techniques.
Innovation Solution
A native SCX-MS method involving immunoprecipitation with agarose beads and digestion by IdeS enzyme to produce Fab2 fragments, followed by native SCX-MS analysis, enabling sensitive and robust quantitation of antibodies even at low concentrations in neat solutions or serum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional detection methods are used for therapeutic peptides or proteins in complex matrices like serum, then the analysis can be performed with standard equipment, but the sensitivity and specificity are insufficient to accurately detect low concentrations of antibodies
Solution Approach 1:
The antibody molecule is divided into Fab2 fragments through enzymatic digestion with IdeS. This segmentation reduces the molecular complexity and increases the surface-area-to-volume ratio, enhancing ionization efficiency and detection sensitivity in native SCX-MS analysis while maintaining the ability to detect low concentrations in complex matrices
Solution Approach 2:
Immunoprecipitation using anti-Fc antibody-coated beads serves as an intermediary step to selectively capture and concentrate antibodies from complex serum matrices before digestion and MS analysis. This intermediary purification step removes matrix interference and enriches the target analyte, enabling sensitive detection without requiring overly complex direct analysis methods
2Reliability
If immunoprecipitation with anti-Fc antibody beads is used to capture antibodies from serum, then antibodies can be selectively enriched, but the process requires additional steps and time
Solution Approach 1:
The method merges multiple functions into a streamlined workflow: immunoprecipitation captures antibodies while simultaneously concentrating them from serum; subsequent IdeS digestion releases Fab2 fragments that are directly compatible with native SCX-MS analysis. This merging of enrichment, digestion, and analysis preparation steps into a sequential protocol improves reliability while managing time efficiency through optimized step transitions
3Measurement precision
If native SCX-MS analysis is performed on intact antibodies, then the analysis can be done without extensive sample preparation, but the sensitivity is insufficient for low concentration samples in complex matrices
Solution Approach 1:
Preliminary immunoprecipitation is performed to capture and concentrate antibodies from serum before digestion and MS analysis. This preliminary enrichment action ensures sufficient analyte concentration is achieved before the actual native SCX-MS measurement, enabling sensitive detection of low concentration samples while maintaining relative simplicity in the overall workflow
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 efficiently and accurately quantitates antibodies with a low limit of detection and quantitation, effectively separating antibodies from matrix proteins, demonstrating superior sensitivity and specificity, particularly in complex biological samples like serum.
Implementation Method 1
Immunoprecipitation with agarose beads coated in anti-human Fc antibody may be used to pull down a human antibody in a sample
Implementation Method 2
The digestive enzyme IdeS or a variant thereof may be used to cleave the immobilized antibody, producing a Fab2 fragment
Implementation Method 3
subjecting said eluate to native SCX-MS analysis
Implementation Method 4
native SCX-MS analysis for sensitive and robust quantitation
Data Source
AI summary
The present invention generally pertains to methods of characterizing antibodies and related products. In particular, the present invention pertains to the use of immunoprecipitation and native strong cation exchange chromatography-mass spectrometry to specifically and sensitively detected and quantitate antibodies and related products in a sample.