Mycobacterium bovis Diagnostic Reagent Antigen Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current diagnostic methods for bovine tuberculosis (bTB) in animals, such as the tuberculin skin test and interferon-γ release assays, face challenges in differentiating infected animals from those vaccinated with BCG, due to cross-reactive antigens and poor standardization of stimulating antigens, leading to reduced sensitivity and specificity.
Innovation Solution
A diagnostic reagent comprising specific antigenic proteins or fragments like Rv3616c, Rv1789, Rv3810, and Rv3478 is developed, which can differentiate between infected and vaccinated animals by generating a positive response in skin tests or in vitro assays, enhancing signal strength and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PPD-based tuberculin skin test is used for bTB diagnosis, then the test can detect immune response in infected animals, but it cannot differentiate infected animals from BCG vaccinated animals due to cross-reactive antigens
Solution Approach 1:
The patent segments the antigen composition into specific defined antigens (ESAT-6, CFP-10, Rv3615c) that are present in M. bovis but absent in BCG vaccine strain. This segmentation allows the test to specifically detect infection without cross-reacting with vaccination, thereby differentiating infected from vaccinated animals while maintaining detection sensitivity.
Solution Approach 2:
The patent applies local quality by selecting antigens with specific properties - choosing ESAT-6, CFP-10, and Rv3615c proteins that have distinct presence patterns in pathogenic mycobacteria versus vaccine strains. This localized selection of specific antigenic components enables the test to have different reactivity profiles for infected versus vaccinated animals.
2Reliability
If crude whole cell antigen preparation is used in TST, then the test can stimulate immune response, but the poor standardization of antigens reduces assay sensitivity and specificity
Solution Approach 1:
The patent changes the parameters of antigen definition from crude, variable compositions to precisely defined molecular entities (ESAT-6, CFP-10, Rv3615c proteins with specific amino acid sequences). This parameter change from undefined to defined antigens ensures consistent preparation, storage, and application, improving both reliability and sensitivity of the assay.
Solution Approach 2:
The patent creates a composite antigen formulation combining three specific proteins (ESAT-6, CFP-10, and Rv3615c) that work together to enhance detection capability. This composite approach leverages the complementary properties of each antigen to achieve superior diagnostic performance compared to individual antigens alone.
3Reliability
If SICCT is used to improve test specificity by comparing bovine and avian PPD responses, then cross-reactivity with environmental mycobacteria is reduced, but assay sensitivity is reduced as well
Solution Approach 1:
The patent extracts and utilizes only the specific antigens (ESAT-6, CFP-10, Rv3615c) that are uniquely present in M. bovis and absent in BCG and environmental mycobacteria. By taking out only these relevant antigens and excluding others, the test achieves high specificity without requiring comparative testing, thereby maintaining sensitivity.
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 reagent effectively detects infections with Mycobacterium bovis and tuberculosis by eliciting a strong immune response in infected animals while avoiding false positives from vaccinated individuals, improving the accuracy of bTB diagnosis.
Implementation Method 1
A diagnostic reagent comprising specific antigenic proteins or fragments like Rv3616c, Rv1789, Rv3810, and Rv3478 is developed, which can differentiate between infected and vaccinated animals by generating a positive response in skin tests or in vitro assays
Data Source
AI summary
The invention provides a Mycobacterium Tuberculosis Complex (MTC) (for example, M. bovis and/or M. tuberculosis) diagnostic reagent comprising the reagent components:a. a Rv3616c antigen polypeptide and/or a Rv3616c antigenic cocktail;b. a Rv1789 antigen polypeptide and/or a Rv1789 antigenic cocktail;c. a Rv3810 antigen polypeptide and/or a Rv3810 antigenic cocktail; andd. a Rv3478 antigen polypeptide and/or a Rv3478 antigenic cocktail.The diagnostic reagent may further comprise one or more of a ESAT-6 antigen polypeptide and/or a ESAT-6 antigenic cocktail; a CFP-10 antigen polypeptide and/or a CFP-10 antigenic cocktail; a Rv3615c antigen polypeptide and/or a Rv3615c antigenic cocktail; and/or SEQ ID NO:207 (a fusion protein of ESAT-6 and CFP-10 and Rv3615c). There are also provided methods and kits involving use of the diagnostic reagent.