Doubly-Defective Swinepox Virus Vector for PCV2 Vaccine
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Solution Overview
Problem
Current viral vectors for gene delivery and expression in veterinary vaccines, such as poxviruses, often require cloning foreign gene sequences in non-essential regions, limiting their expression efficiency and stability, and there is a need for new vectors that can efficiently and stably express multiple foreign gene sequences in vivo.
Innovation Solution
Development of doubly-defective recombinant swinepox viruses (rSPVs) with defective IL18bp and TK or ARP genes, allowing for the insertion and expression of one or more foreign gene sequences, which are highly attenuated and stable, enabling efficient gene delivery and immune response in swine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If foreign gene sequences are cloned in non-essential regions of poxvirus, then the virus can still replicate, but the expression efficiency and stability of foreign genes is limited
Solution Approach 1:
The invention extracts and removes the thymidine kinase (TK) gene from the poxvirus genome, creating a TK-defective viral vector. This extraction eliminates the harmful constraint of limited cloning sites while maintaining viral replication capability through complementation, thereby improving both foreign gene expression efficiency and stability
Solution Approach 2:
The TK-defective viral vector creates a universal platform that can accommodate multiple foreign gene sequences at various cloning sites within the virus genome. This multi-functional design allows simultaneous expression of multiple antigens or therapeutic proteins, enhancing productivity while maintaining reliability through the essential TK gene provided in trans
2Adaptability or versatility
If more foreign gene sequences are inserted into the virus, then the vaccine can protect against multiple pathogens, but the virus stability and replication efficiency may decrease
Solution Approach 1:
The invention segments the viral genome into essential regions (maintained for stability) and non-essential regions (used for foreign gene insertion). The TK-defective vector provides a stable backbone with defined cloning sites, allowing multiple foreign genes to be inserted without compromising overall viral genome stability
Solution Approach 2:
The TK gene provided in trans acts as an intermediary that mediates between the TK-defective viral genome and the host cell. This intermediary allows the virus to replicate and maintain stability while accommodating multiple foreign gene insertions at various cloning sites throughout the genome
3Object-affected harmful factors
If the virus is highly attenuated for safety, then it is safer for vaccination, but the immune response strength may be reduced
Solution Approach 1:
The invention converts the harmful potential of viral replication into a benefit by creating a TK-defective virus that cannot replicate independently. This forced dependency on complementation systems creates a highly attenuated, safe vaccine platform that still elicits strong immune responses through controlled expression of foreign antigens
Data Source
AI summary
The present invention relates to novel recombinant swinepox viruses and their use in vaccine compositions. The recombinant swinepox viruses of the invention are doubly defective for IL18bp and TK genes, and comprise at least one foreign gene cloned into defective TK gene sequence. The invention is particularly suited to produce swine vaccines, particularly for vaccinating swine against PCV2 infection.