ESAT-6 and CFP-10 Peptide Composition for Low-Grade Infection Detection

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Solution Overview

Problem

Existing immunological-based diagnostic assays lack sufficient sensitivity and selectivity to detect low-grade infections or persistent low-level infections, particularly in subjects with active or latent infectious disease states, necessitating the development of more sensitive and selective antigen compositions and diagnostic assays.

Innovation Solution

A composition comprising fragments of ESAT-6 and CFP-10 peptides, specifically a first set of 7 to 14 amino acids and a second set of 16 amino acids or greater, enhances the sensitivity of cell-mediated immune response assays by stimulating both CD4+ and CD8+ T-cells, optionally with the addition of a non-reducing sugar like trehalose to increase assay sensitivity and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional immunological-based diagnostic assays are used, then the assay can detect immune response, but the sensitivity is insufficient to detect low-grade or persistent low-level infections

Engineering Contradiction:
Improvesensitivity of detectionVSAvoidability to detect low-grade infection
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent segments the antigen into multiple peptide sets with different length characteristics. Set 1 contains peptides of 7-14 amino acids that are highly immunogenic and stimulate strong T-cell responses, while Set 2 contains peptides of 16+ amino acids that provide broader antigen coverage. This segmentation allows the assay to detect both high-grade and low-grade infections by capturing different aspects of the immune response.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a composite antigen composition by combining peptide sets with different length characteristics (7-14mer and 16+mer peptides) from the same or different protein antigens. This composite approach leverages the complementary strengths of each peptide type: the short peptides provide high immunogenicity for sensitive detection, while the long peptides provide comprehensive antigen representation, resulting in enhanced overall assay sensitivity and reliability.

Inventive Principle:
Principle #40Composite materials

2Measurement precision

If a single antigen or peptide is used in the assay, then the assay design is simple, but the sensitivity and selectivity are insufficient for routine diagnostic application

Engineering Contradiction:
Improvesensitivity and selectivityVSAvoidassay composition complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the antigen into multiple peptide sets (Set 1 with 7-14mer peptides and Set 2 with 16+mer peptides) that can be independently characterized and prepared. This segmentation allows for systematic optimization of each peptide set's contribution to assay performance while maintaining a structured, manageable composition that balances sensitivity enhancement with practical assay design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent designs a universal peptide composition framework that can be applied to detect infections by various pathogens. By using peptide sets from the same or different protein antigens depending on the specific pathogen being tested, the same basic assay structure and methodology can be universally applied across different diagnostic applications, reducing overall system complexity while maintaining high sensitivity and selectivity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250368693A1Peptide composition and uses thereof
Publication Date: 2025.12.04 QIAGEN SCIENCES LLC

AI summary

Subject of the invention is a composition comprising at least one fragment of the peptide ESAT-6 and at least one fragment of the peptide CFP-10. Preferably, the fragments comprise at least two sets of peptides, a first set comprising at least one peptide of from about 7 to 14 amino acid residues in length and a second set comprising at least one peptide of from 16 amino acid residues or greater. The invention also relates to diagnostic methods using the composition.