Fluorescent Neutralization Assays Using Inactivated Virus

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Solution Overview

Problem

Current virus neutralization assays, such as PRNT and IFA, face challenges including the use of live viruses, lengthy incubation times, safety concerns, and limited sensitivity, making them cumbersome and unsuitable for high-throughput testing.

Innovation Solution

A rugged, reliable, and sensitive laboratory method using inactivated, fluorescently-labeled viruses with flow cytometric monitoring, specifically employing a BioPlex bead array reader for rapid and cost-effective analysis, which allows for the measurement of neutralizing capacity at low concentrations of sera and antibodies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If live virus is used in neutralization assays, then the assay can accurately measure viral infectivity, but safety concerns and extensive safety precautions are required

Engineering Contradiction:

Improveviral infectivity measurementVSAvoidsafety concerns

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent uses inactivated virus particles that retain the structural features and antigenic properties of live virus but cannot replicate or cause infection. These inactivated virus copies allow measurement of neutralizing antibodies without the harmful effects of live virus, resolving the contradiction between measurement accuracy and safety

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent converts the potentially harmful live virus into a beneficial inactivated form that can be safely handled while still providing the necessary viral antigens for neutralization assays. The inactivation process preserves the virus's ability to bind antibodies while eliminating its pathogenicity

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Measurement precision

If traditional PRNT or IFA methods are used, then virus neutralization can be assessed, but the assay time is lengthy (several days)

Engineering Contradiction:

Improveneutralization assessmentVSAvoidassay time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the complex multi-day culture and fixation procedures of traditional PRNT and IFA with a simplified flow cytometry-based method. By using inactivated virus and direct fluorescent labeling, the assay eliminates the need for prolonged cell culture incubation while maintaining neutralization detection capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent performs virus inactivation and fluorescent labeling in advance, preparing the virus reagent beforehand. This preliminary preparation allows the actual neutralization assay to be completed rapidly without requiring time-consuming live virus culture steps during the assay execution

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If traditional flow cytometry is used for virus labeling, then sensitivity is improved, but the cost is high

Engineering Contradiction:

Improvedetection sensitivityVSAvoidcost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent uses inactivated virus particles as disposable labeling targets that can be prepared and used without the need for expensive, sophisticated flow cytometry equipment. The inactivated virus serves as a stable, reusable labeling substrate that reduces dependence on costly instrumentation while maintaining detection sensitivity

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 reduces assay time to a few hours, enhances sensitivity, and is suitable for high-throughput screening, while eliminating the need for extensive safety precautions due to the use of inactivated viruses, offering a cost-effective solution compared to traditional flow cytometry.

Implementation Method 1

incubating a population of target cells with the mixture under conditions permitting endocytosis of the labeled virus by the target cells

Methodology Applied

Scientific EffectEndocytosis:

Implementation Method 2

measuring fluorescence of labeled virus endocytozed by the target cells

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Data Source

PatentUS9541545B2Fluorescent neutralization and adherence inhibition assays

Publication Date: 2017.01.10 SANOFI PASTEUR VAXDESIGN CORP

AI summary

The present invention comprises rugged, inexpensive, reliable, and sensitive laboratory assays of antibody-based viral neutralization activity and antibody-based viral adherence inhibition activity. The assays use inactivated, fluorescently-labeled virus, allowing the tests to be performed without extensive safety precautions. The interaction of the labeled virus with target cells is monitored using flow cytometric methods. A preferred embodiment uses simple and inexpensive flow cytometry methodologies and equipment, such as bead array readers used as simplified flow cytometers. The assays are rapid, taking no longer than a few hours and are readily conducted by a trained technician. The assays are sensitive because they use labeled viruses at low concentrations and determine neutralizing and blocking capacity of sera and antibody at low concentrations. The methods are appropriate for high-throughput screening of large panels of samples.