Polysaccharide Vaccine Molecule with Cap Structure for DIVA Testing
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Solution Overview
Problem
Current vaccines for brucellosis, such as B. abortus S19 and B. melitensis Rev1, face challenges including residual virulence, antibiotic resistance, and the inability to differentiate between infected and vaccinated animals due to antibody induction issues, limiting their effectiveness and safety, especially in livestock.
Innovation Solution
A novel vaccine molecule comprising a chain of seven or more contiguous units of 4,6-dideoxy-4-acylamido-α-pyranose with a cap structure that disrupts a specific epitope, allowing for the development of a DIVA (Differentiating Infected from Vaccinated Animals) test system by preventing antibody binding to universal and DIVA antigens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional vaccines (B. abortus S19, B. melitensis Rev1) are used, then protective immunity is provided, but the ability to differentiate infected from vaccinated animals is lost due to antibody induction against OPS
Solution Approach 1:
The invention extracts and modifies the OPS structure by removing the terminal 4,6-dideoxy-4-acylamido-α-pyranose unit and replacing it with a cap structure. This extraction of the problematic terminal unit eliminates antibody induction against the cap structure itself, while preserving protective immunity through the remaining OPS chain that still contains protective epitopes.
Solution Approach 2:
The invention applies local quality modification by specifically altering only the terminal region of the OPS molecule while leaving the rest of the polysaccharide chain intact. The cap structure is placed locally at the terminal position, providing the specific property of being non-immunogenic at that location while maintaining the immunogenicity and protective function of the internal regions.
2Measurement precision
If rough strain vaccines (B. abortus RB51) are used to avoid serological reactions, then differentiation is possible, but protective efficacy is reduced and virulence control is compromised
Solution Approach 1:
The invention changes the structural parameters of the OPS molecule by modifying the terminal unit configuration. This parameter change creates a novel immunogenic profile that induces antibodies against the intact terminal unit, enabling differentiation while maintaining protective efficacy through the preserved internal OPS structure and epitopes.
3Reliability
If smooth strain vaccines are used, then protective immunity is enhanced, but serological differentiation becomes impossible due to OPS antibody induction
Solution Approach 1:
The invention segments the OPS molecule into distinct functional regions: a modified terminal region with the cap structure that provides differentiation capability, and an internal region that maintains protective immunity. This segmentation allows the vaccine to simultaneously provide both protection and diagnostic differentiation without requiring complex external test systems.
Data Source
AI summary
There is provided a molecule comprising a chain of seven or more contiguous units of 4,6-dideoxy-4-acylamido-α-pyranose each pair of units joined by a C1-C2 or a C1-C3 link, the chain having a terminal end and a reducing end, wherein the pyranose ring in the unit of the chain most distal from the reducing end is linked to a cap structure. The cap structure is not a 4,6-dideoxy-4-acylamido-α-pyranose. There are also provided vaccine compositions comprising the molecule and methods of vaccinating an animal against infection by a Brucella organism, including methods of distinguishing between a vaccinated and an infected animal. There are further provided novel methods of detecting the presence in a sample of an anti-Brucella antibody.