Segmented HIV gp41 Antigens for False-Positive Reduction

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Solution Overview

Problem

Existing immunoassays fail to effectively distinguish between existing technologies for detecting antibodies against HIV, and the technical problem is the provision of means and methods to avoid false positive results in in vitro diagnostic immunoassays for detecting HIV antibodies.

Innovation Solution

A composition comprising at least two individual HIV gp41 antigens, with one antigen comprising SEQ ID NO: 1 and the other comprising SEQ ID NO: 2 or 3, is used to detect antibodies in a sample, produced by culturing host cells, expressing the antigens, and purifying them to form a composition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wild type HIV gp41 is used as antigen in immunoassays, then high specificity for detecting HIV antibodies is achieved, but false positive results occur

Engineering Contradiction:

Improvespecificity of HIV antibody detectionVSAvoidfalse positive rate

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The gp41 antigen is divided into multiple domains (N-terminal heptad repeat, C-terminal heptad repeat, and loop motif). The invention selectively uses only the N-terminal and C-terminal heptad repeat domains while excluding the loop motif domain, creating a segmented antigen composition that maintains specificity while reducing false positives

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The loop motif domain is extracted and removed from the gp41 antigen composition. This domain is specifically identified as the source of false positive reactions, and its removal while retaining the immunogenic heptad repeat domains resolves the contradiction between maintaining specificity and eliminating false positives

Inventive Principle:

Principle #2Taking out (Extraction)

2Ease of manufacture

If gp41 variants are engineered to be soluble, then expression and detection are improved, but false positive results are not completely avoided

Engineering Contradiction:

Improvesolubility and expression of gp41VSAvoidfalse positive rate in immunoassays

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention applies local quality by making specific regions of the gp41 molecule soluble (the heptad repeat domains) while excluding the problematic loop motif region. This localized approach to solubility engineering maintains manufacturability while addressing the false positive issue through selective domain inclusion

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

The composition achieves high specificity and sensitivity in detecting HIV antibodies, reducing false positive results in immunoassays.

Implementation Method 1

a first binding partner specific for an HIV antibody in the isolated sample is bound to a second binding partner in a sandwich format

Methodology Applied

Scientific EffectAntigen-antibody binding:

Data Source

PatentUS20250298022A1HIV gp41 variants for immunodiagnostic assays

Publication Date: 2025.09.25 ROCHE DIAGNOSTICS OPERATIONS INC

AI summary

The invention relates to novel HIV gp41 antigen compositions that are suitable for detecting antibodies against HIV in an isolated biological sample providing high specificity immunoassay results. It further relates to methods detecting HIV antibodies, use of novel HIV gp41 antigen compositions in immunoassays as well as to reagent kits comprising novel HIV gp41 antigen compositions.