Recombinant PRV Vaccine Expressing PCV2 Capsid Protein
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Solution Overview
Problem
Current methods for constructing recombinant pseudorabies virus (PRV) vaccines are complex, inefficient, and require multiple steps, leading to a low success rate in expressing exogenous immunogens on viral particles, which limits the effectiveness of bi- or polyvalent vaccines for pig breeding.
Innovation Solution
A recombinant PRV particle is developed that expresses an exogenous immunogen, such as the porcine circovirus 2 capsid protein, on its envelope by replacing a non-essential envelope protein gene sequence with the immunogen coding sequence, using a single homologous recombination step and enhanced green fluorescent protein (EGFP) as a screening marker, allowing for faster and more efficient virus rescue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional methods are used to construct recombinant PRV vaccines by replacing original genes or inserting exogenous genes directly into the PRV genome, then the vaccine can express exogenous immunogens in host cells, but the construction process becomes complex and inefficient with low success rate
Solution Approach 1:
The patent uses a transfer vector as an intermediary carrier to deliver exogenous immunogen genes to the PRV genome. This vector-mediated approach simplifies the construction process by providing a standardized, efficient recombination system rather than direct genome manipulation, thereby improving success rate while managing complexity.
Solution Approach 2:
The patent performs preliminary selection by expressing exogenous immunogens on the surface of rescued virus particles before full-scale production. This allows early verification of successful recombination and immunogen expression, improving overall success rate by filtering out failed constructs early in the process.
2Reliability
If multiple immunizations are administered to pigs to achieve immune protection against different pathogens, then comprehensive immune coverage is achieved, but immune stress increases leading to elevated body temperature, anorexia, metabolic changes, slowed growth, and extended feeding cycles
Solution Approach 1:
The patent merges multiple immunogen expressions into a single recombinant PRV vaccine platform. By co-expressing exogenous immunogens (such as PCV2 capsid protein) alongside PRV antigens on the same viral particle, the vaccine provides multi-pathogen protection through one immunization, eliminating the need for multiple separate vaccines and reducing immune stress on pigs.
3Reliability
If exogenous genes are inserted into the PRV genome to express protective antigens, then the vaccine can stimulate host immune response, but the immune protection has a lag because host cells must be infected by live vaccines first before antigen expression
Solution Approach 1:
The patent performs preliminary display of exogenous immunogens on the surface of rescued virus particles during the construction and selection phase. This allows verification of immunogen expression before the vaccine is administered to hosts, ensuring that the vaccine is pre-configured to elicit immediate immune recognition upon administration, thereby reducing the lag time.
4Reliability
If traditional recombinant virus construction methods are used requiring multiple steps and screening, then the process can achieve virus rescue, but the process becomes time-consuming and labor-intensive
Solution Approach 1:
The patent uses EGFP (enhanced green fluorescent protein) as a visual screening marker to identify successfully rescued recombinant virus particles. The fluorescent signal provides immediate, easy-to-detect identification of positive clones, eliminating the need for complex multi-step screening procedures and significantly reducing the time and labor required for virus construction and verification.
Data Source
AI summary
The present disclosure provides a pseudorabies virus (PRV) expressing a porcine circovirus 2 (PCV2) capsid protein in its envelope, and use thereof. In the present disclosure, an attenuated PRV vaccine strain is used as a vector to express an exogenous immunogen. The exogenous immunogen only replaces an extracellular domain of a non-essential envelope protein of the PRV, while retaining a transmembrane domain and an intracellular domain of an original envelope protein, thereby allowing the expression of one or more exogenous immunogens on the viral envelope without changing genes of other PRV autoimmunogens. During the recombinant PRV particle being recognized by the body's immune system, the host's immune system recognizes all immunogens (exogenous immunogens and PRV autoimmunogens) on the recombinant PRV particle and then initiates an immune response, thus exerting a protective effect of a bivalent vaccine or a polyvalent vaccine based on the recombinant PRV particle.