Inert Reference Antibody Corrects Brain Tissue Measurement Errors

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Solution Overview

Problem

Current methods for determining the amount of therapeutic antibodies transported across the blood-brain barrier into the brain are inaccurate due to interference from residual blood, leading to overestimation of antibody concentrations in brain tissue samples.

Innovation Solution

A method involving the use of an inert reference antibody that does not cross the blood-brain barrier is applied to correct for residual blood-derived therapeutic antibody in brain lysate samples, allowing for precise determination of the therapeutic antibody concentration in the brain tissue.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If direct measurement of therapeutic antibody in brain tissue is performed without correction, then the measurement process is simple, but the measurement precision is poor due to overestimation from residual blood

Engineering Contradiction:
Improveaccuracy of therapeutic antibody concentration measurementVSAvoidcomplexity of measurement method
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

An inert reference antibody that does not cross the blood-brain barrier is introduced as an intermediary substance. This reference antibody binds to residual blood in the brain tissue sample, allowing the quantification and subtraction of blood-derived therapeutic antibody from the total measurement, thereby correcting the overestimation error

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The method changes the measurement parameters by performing two separate immunoassay measurements: one for total therapeutic antibody concentration and another for reference antibody concentration. By measuring and comparing these different parameters, the blood contamination contribution is calculated and subtracted to obtain the corrected brain tissue antibody concentration

Inventive Principle:
Principle #35Parameter changes

2Reliability

If residual blood is not accounted for in the measurement, then the ease of operation is high, but the reliability of the measurement result is poor

Engineering Contradiction:
Improveaccuracy of brain antibody concentration dataVSAvoidsimplicity of sample processing procedure
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The reference antibody is administered to the animal before sacrifice and brain sample collection. This preliminary action ensures that by the time of sampling, the reference antibody has equilibrated in the blood and can serve as a reliable marker for quantifying residual blood volume in the brain tissue lysate

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The measurement process incorporates feedback by using the reference antibody measurement result to correct the therapeutic antibody measurement. The calculated blood-derived antibody amount from the reference antibody assay is subtracted from the total therapeutic antibody measurement, providing a feedback correction that improves result reliability

Inventive Principle:
Principle #23Feedback

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 a robust and accurate measurement of therapeutic antibodies in brain tissue by accounting for residual blood, reducing errors and ensuring that only brain-located antibody concentrations are reported.

Implementation Method 1

Therefore, e.g., an immunoassay, such as, ELISA, RIA, protein blot (Western blot) assay, and the like can be used

Methodology Applied
Scientific EffectImmunoassay:

Data Source

PatentEP4085251B1Method for determining the amount of a therapeutic antibody in the brain
Publication Date: 2024.07.31 F HOFFMANN LA ROCHE & CO AG
  • EP4085251B1 patent drawingFigure 1
  • EP4085251B1 patent drawingFigure 2
  • EP4085251B1 patent drawingFigure 3

AI summary

Herein is reported a method for determining the concentration of a therapeutic antibody in a tissue of an experimental animal to whom the therapeutic antibody had been administered, wherein the interference from residual blood in a tissue sample of the experimental animal, which is used for determining the concentration of the therapeutic antibody in said tissue, is reduced, wherein the concentration of the therapeutic antibody in the tissue of the experimental animal is calculated with the following formula: (I) wherein CtmAb,tissue,det. = obtained by determining the concentration of the therapeutic antibody in the tissue sample of the experimental animal, CtmAb,plasma,det. = obtained by determining the concentration of the therapeutic antibody in a blood sample of the experimental animal directly prior to taking the tissue sample, CrefmAb,tissue,det. = obtained by determining the concentration of the inert reference antibody in the tissue sample of the experimental animal, CrefmAb,plasma,det. = obtained by determining the concentration of an inert reference antibody in the blood sample of the experimental animal directly prior to taking the tissue sample, Ctissue,sample = obtained by determining the tissue concentration in the tissue sample, whereby the inert reference antibody does not penetrate into said tissue, whereby the inert reference antibody is administered 2 to 10 minutes prior to obtaining the tissue and blood sample.