Modified PCV2 ORF2 VLPs for DIVA Vaccine Differentiation
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Solution Overview
Problem
Current methods for differentiating between infected and vaccinated animals in the context of viral outbreaks, such as PCV2, face challenges due to logistical and economic limitations, including expensive virological testing and the difficulty in scaling up DIVA (Differentiating Infected from Vaccinated Animals) systems, which struggle to distinguish between infected and vaccinated individuals effectively.
Innovation Solution
The development of a virus-like particle (VLP) based on a modified PCV2 ORF2 protein with amino acid residues replaced in the BC loop to present an epitope of interest, allowing for the production of VLPs that trigger an immune response while maintaining antigenic properties, enabling effective immunization and differentiation between infected and vaccinated animals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If virological testing is used to differentiate between infected and vaccinated animals, then measurement precision is improved, but cost increases significantly
Solution Approach 1:
The patent uses a recombinant protein copy of the viral capsid protein (expressed in insect cells) as a surrogate for the actual virus in vaccine formulations. This allows differentiation testing to target only the recombinant vaccine component rather than requiring complex virological testing to distinguish wild-type virus from vaccine virus, significantly reducing cost while maintaining differentiation accuracy
Solution Approach 2:
The patent extracts and isolates the specific capsid protein antigen from the virus and expresses it recombinantly. This extracted antigen becomes the target for serological testing, allowing simple ELISA-based differentiation between vaccinated animals (who have antibodies against the recombinant capsid) and naturally infected animals (who have antibodies against additional viral components not present in the vaccine)
2Productivity
If DIVA systems are scaled up for widespread use, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex virological testing systems with a simplified recombinant protein-based approach. The recombinant capsid protein serves as a standardized, scalable substitute for whole virus testing, enabling simple ELISA assays to be implemented widely without complex infrastructure
Solution Approach 2:
The patent replaces mechanical/virological testing methods (requiring cell culture, virus propagation, and complex assay procedures) with immunological testing based on recombinant protein antigens. This substitution enables high-throughput ELISA-based serology that is far more scalable and less complex than traditional virological DIVA systems
3Adaptability or versatility
If modified PCV2 ORF2 protein with replaced amino acid residues is used to produce VLPs, then adaptability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality modification by replacing only specific amino acid residues in the BC loop region of the ORF2 capsid protein while leaving the rest of the protein structure unchanged. This localized modification allows presentation of specific epitopes of interest while maintaining the overall VLP structure and self-assembly properties, balancing adaptability with manufacturing feasibility
Data Source
AI summary
The present invention relates to an immunogen-carrier, wherein the immunogen-carrier is preferably a virus-like particle (VLP) composed of a plurality of a modified PCV2 ORF2 protein. In particular, the present invention belongs to the field of compliance markers and marker vaccines which allow for the differentiation between infected and vaccinated individuals. In particular, it relates to a compliance marker for vaccines including a subunit antigen, and a DIVA (Differentiating Infected from Vaccinated Animals) system which makes it possible to differentiate between animals infected with a pathogen and animals treated with a subunit antigen derived from said pathogen.