Therapeutic Antibody Quantification via Mass Spectrometry
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Solution Overview
Problem
Current methods for quantifying therapeutic antibodies in human plasma and serum samples are challenging due to their polypeptide nature, high homology with endogenous human IgGs, and low concentrations, leading to difficulties in accurately determining pharmacokinetic properties and requiring lengthy assay development times and custom reagents.
Innovation Solution
A method involving the addition of labeled forms of therapeutic antibodies to a sample, followed by enzyme proteolysis to generate peptides, which are then analyzed by mass spectrometry to determine the antibody concentration, allowing for accurate quantification irrespective of the specific antibody type and presence of other antibodies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ELISA methods are used for antibody quantification, then the assay is fast and sensitive, but the assay development time is long and custom reagents are required
Solution Approach 1:
The patent replaces the immunoassay-based ELISA method with mass spectrometry-based quantification. This substitution eliminates the need for custom reagent development and lengthy optimization procedures, reducing assay development time from months to days while maintaining sensitivity through direct detection of antibody peptides.
Solution Approach 2:
The mass spectrometry method provides a universal platform that can quantify multiple different therapeutic antibodies using the same assay conditions and reagents. A single mass spectrometry assay can measure concentrations of various IgG therapeutic antibodies without requiring antibody-specific customization, enabling multi-functionality across different antibody types.
2Productivity
If conventional ELISA methods are used for antibody quantification, then the assay is fast, but matrix interference is common and specificity is reduced
Solution Approach 1:
The patent replaces ELISA's antibody-antigen binding mechanism with mass spectrometry's physical detection of peptide mass and fragmentation patterns. This substitution eliminates non-specific binding to plasma proteins and matrix interference, as mass spectrometry directly measures the intrinsic physical-chemical properties of the antibody peptides rather than relying on binding interactions that can be affected by sample matrix.
Solution Approach 2:
The patent changes the detection parameter from binding signal (ELISA) to mass-to-charge ratio and fragmentation pattern (mass spectrometry). By measuring the intrinsic mass and fragmentation characteristics of antibody-derived peptides, the method achieves high specificity that is independent of sample matrix composition, eliminating cross-reactivity and non-specific binding issues.
3Measurement precision
If mass spectrometry is used for protein quantification, then specificity is high and matrix interference is rare, but custom reagents are still needed for ELISA-based approaches
Solution Approach 1:
The patent establishes a universal mass spectrometry-based quantification platform that can measure multiple therapeutic antibodies using the same reagents and assay conditions. The method uses stable isotope-labeled internal standards and generic proteolytic digestion that work across different antibody types, eliminating the need for antibody-specific reagent development and simplifying the overall reagent requirements.
4Reliability
If therapeutic antibodies with high homology to endogenous human IgGs are quantified, then cross-reactivity occurs, but differentiation between therapeutic and endogenous antibodies is difficult
Solution Approach 1:
The patent applies local quality by introducing stable isotope labels at specific positions on the therapeutic antibodies. These labels create localized mass differences that are detectable by mass spectrometry, allowing differentiation of therapeutic antibodies from endogenous IgGs based on their labeled peptide fragments rather than overall sequence homology.
Solution Approach 2:
The patent changes the detection parameter from sequence-based recognition (which cannot distinguish homologous antibodies) to mass-based detection using stable isotope labels. By measuring the mass-to-charge ratio of peptide fragments containing the isotopic labels, the method achieves accurate differentiation between therapeutic and endogenous antibodies despite their high sequence homology.
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 enables precise, sensitive, and reproducible quantification of therapeutic antibodies, simplifying the process and reducing the need for specific kits or methods based on the antibody type, and can handle multiple antibodies present in a sample.
Implementation Method 1
subjecting the pre-proteolysis sample to an enzyme proteolysis, so as to provide a proteolysis sample comprising (i) proteolysis labeled peptides derived from the labeled therapeutic antibodies
Implementation Method 2
determining by mass spectrometric analysis the ratio between (i) one or more selected proteolysis labeled peptides and (ii) one or more corresponding proteolysis peptides derived from the said therapeutic antibody
Data Source
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AI summary
The present invention relates to a method for quantifying a therapeutic antibody in a sample of a human individual comprising a step of adding to a test sample which may contain therapeutic antibodies to be quantified a known amount of two or more labeled forms of said therapeutic antibodies.