Avidity Index Calculation Using Isolated Antigens
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current serologic tests for detecting IgM and IgG antibodies in toxoplasmosis and cytomegalovirus infections face significant inter-assay variability due to the lack of standardized antigens, and existing methods for determining antibody avidity often rely on hazardous chaotropic reagents, which can cause aberrant results and cross-contamination.
Innovation Solution
A method involving two assays with differential antigen exposure to distinguish between low and high avidity IgG antibodies by using isolated antigens from Toxoplasma gondii or cytomegalovirus, where the ratio of signals in the presence and absence of chaotropic agents is used to calculate an Avidity Index, eliminating the need for chaotropic reagents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If chaotropic reagents are used to determine antibody avidity, then the ability to distinguish between low and high avidity antibodies is improved, but hazardous conditions and cross-contamination risks are introduced
Solution Approach 1:
The invention extracts and eliminates the hazardous chaotropic reagents from the avidity determination process. Instead of using urea or other chaotropic agents to differentiate antibody avidity, the patent employs a two-assay approach with isolated antigens and differential antigen exposure that achieves the same diagnostic purpose without hazardous chemicals.
Solution Approach 2:
The invention introduces an intermediary approach using isolated antigens and controlled antigen exposure as mediators to differentiate antibody avidity. Rather than directly using hazardous reagents to disrupt antibody-antigen complexes, the patent uses carefully controlled antigen exposure conditions to indirectly assess avidity through competitive binding mechanisms.
2Measurement precision
If standardized isolated antigens are used, then inter-assay variability is reduced, but antigen preparation complexity increases
Solution Approach 1:
The invention applies preliminary action by pre-preparing and storing isolated antigens under standardized conditions before use in assays. The antigens are purified, characterized, and stored as ready-to-use reagents, eliminating the need for laboratories to perform complex antigen preparation procedures and ensuring consistency across different assay runs and laboratories.
Solution Approach 2:
The invention applies parameter changes by establishing specific, standardized parameters for antigen preparation including purity thresholds, concentration ranges, and storage conditions. These standardized parameters ensure that antigens produced in different laboratories or batches are equivalent, reducing inter-assay variability while providing clear guidance for antigen preparation.
3Measurement precision
If two-assay differential exposure method is used, then avidity differentiation accuracy is improved, but assay time and complexity increase
Solution Approach 1:
The invention applies dynamics by implementing an automated assay system that dynamically manages the two-assay process. The system automatically performs sequential antigen exposures, controls incubation times, manages washing steps, and calculates avidity indices, reducing the manual time investment required while maintaining the diagnostic accuracy of the differential exposure method.
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 reliable and safe method to determine antibody avidity, reducing inter-assay variability and avoiding the hazards associated with chaotropic reagents, thereby improving diagnostic accuracy for acute and chronic infections.
Implementation Method 1
coating the at least one isolated antigen onto a solid phase to create a solid phase antigen
Implementation Method 2
contacting a test sample from the patient with a liquid phase comprising no infectious antigen and then with the coated solid phase for a time and under conditions sufficient for formation of antibody/antigen complexes to bind high and low avidity IgG to said solid phase
Implementation Method 3
adding a conjugate to the first and second assays for a time and under conditions sufficient for formation of anti-IgG/antibody/antigen complexes, wherein the conjugate comprises an anti-IgG antibody attached to a signal-generating compound capable of generating a detectable signal
Data Source
Figure 1
Figure 2
AI summary
The present invention relates to methods of determining anti-infectious agent IgG avidity, for example, human anti-cytomegalovirus and human anti-toxoplasma IgG, using a competitive assay format.