Peptide-Loaded HLA Class II Antigens for Accurate Reactivity Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current HLA antibody detection methods, particularly single antigen bead (SAB) assays, face challenges in accurately determining transplant compatibility due to discordant results between cell-based and bead-based assays, especially for Class II antibody reactivities, which cannot be fully explained by amino acid motifs, leading to uncertainties in transplant outcomes.

Innovation Solution

The method involves creating a panel of HLA Class 2 antigens with different peptides bound to their peptide binding grooves, specifically using peptides derived from amino acids 119-148 of the HLA Class 1 heavy chain, to determine antibody reactivity, and utilizing solid substrates such as beads to simulate the distribution of HLA antigens in a normal human population, thereby enhancing the accuracy of transplant compatibility testing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If single antigen bead (SAB) assays are used for HLA antibody detection, then the throughput and efficiency are improved, but the measurement precision and reliability are reduced due to discordant results between cell-based and bead-based assays

Engineering Contradiction:

ImprovethroughputVSAvoiddetection accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent introduces peptide-loaded HLA Class II antigens as an intermediary element to bridge the gap between cell-based and bead-based assays. By loading peptides derived from HLA Class I heavy chains onto HLA Class II antigens presented on beads, the assay mimics the natural peptide presentation process, thereby improving detection accuracy while maintaining the high throughput of bead-based systems.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the biochemical parameters of the bead-based assay by introducing specific peptides (derived from amino acids 119-148 of HLA Class I heavy chain) into the HLA Class II antigen structure. This parameter change allows the beads to present more physiologically relevant antigens, resolving the discordance between cell-based and bead-based assay results.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If traditional HLA Class II antigens are used without peptide loading, then the device complexity is reduced, but the measurement precision is insufficient due to inability to detect peptide-dependent antibody reactivities

Engineering Contradiction:

Improveassay complexityVSAvoidantibody reactivity detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by pre-loading HLA Class II antigens with specific peptides derived from HLA Class I heavy chains before presenting them on beads. This preliminary peptide loading step ensures that the antigens are in a physiologically relevant state, enabling accurate detection of peptide-dependent antibody reactivities without significantly increasing overall assay complexity.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If peptides derived from HLA Class I heavy chain are bound to HLA Class II antigens, then the measurement precision is improved by accounting for peptide-dependent reactivities, but the manufacturing precision requirements are increased

Engineering Contradiction:

Improvereactivity detection accuracyVSAvoidpeptide binding control

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent applies local quality by focusing peptide loading on a specific region (amino acids 119-148) of the HLA Class I heavy chain. This localized approach allows for controlled peptide synthesis and binding while maintaining manufacturing feasibility. The specific peptide sequence is designed to bind to HLA Class II antigens with appropriate affinity, balancing detection precision with manufacturing practicality.

Inventive Principle:

Principle #3Local quality

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 improves the accuracy of HLA antibody detection by accounting for peptide-dependent reactivities, reducing discordant results and enhancing the reliability of virtual crossmatching, thus improving transplant outcomes by ensuring better donor-recipient compatibility.

Implementation Method 1

creating a panel of HLA Class 2 antigens with different peptides bound to their peptide binding grooves

Methodology Applied

Scientific EffectPeptide binding to HLA antigen:

Implementation Method 2

contacting a sample containing antibodies specific for at least one HLA Class 2 antigen with at least two of the same HLA Class 2 antigens with different peptides bound thereto

Methodology Applied

Scientific EffectAntibody-antigen binding:

Data Source

PatentUS20250216401A1Method of detecting human leukocyte antigens (HLA)

Publication Date: 2025.07.03 THE TERASAKI INNOVATION CENT

AI summary

Described herein are materials and methods for determining whether antibody reactivity against an HLA Class 2 antigen is dependent upon the presence of a peptide bound to the peptide binding groove thereof.