Infectious cDNA Clone of European PRRS Virus for Vaccine Development
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Solution Overview
Problem
There is a lack of available infectious cDNA clones of the European genotype I PRRS virus, which hinders the understanding and development of vaccines, therapeutics, and diagnostics for Porcine Reproductive and Respiratory Syndrome (PRRS), a significant viral disease affecting swine.
Innovation Solution
A nucleic acid molecule encoding a genotype I PRRS virus with at least 94% sequence identity to a specific sequence is provided, capable of producing infectious virus when transfected into cells, allowing for the replication and induction of PRRS in swine, and can be used to develop attenuated strains for vaccine composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If infectious cDNA clones of European genotype I PRRS virus are used, then the understanding of PRRS and development of vaccines, therapeutics and diagnostics is improved, but such clones are currently unavailable
Solution Approach 1:
The patent creates a synthetic cDNA copy of the European genotype I PRRS virus genome based on the Lelystad virus sequence. This copying approach allows reproduction of the viral genome in vitro, enabling research applications without requiring the original virus isolate. The synthetic clone includes the complete viral genome with specific mutations that maintain infectivity while providing research utility.
Solution Approach 2:
The patent introduces specific parameter changes to the viral genome sequence, including mutations at positions 181 (T→C), 623 (A→C), 1561 (T→C), and others, to create an infectious clone that replicates the European genotype I characteristics. These parameter changes in the nucleotide sequence enable the clone to maintain viral infectivity while providing a stable platform for research.
2Productivity
If the nucleic acid molecule is used to produce infectious virus, then the ability to induce PRRS in swine is improved, but the complexity of virus production and characterization increases
Solution Approach 1:
The patent divides the viral genome into manageable segments for cloning and manipulation. The cDNA sequence is organized into specific regions (5' UTR, ORF1a, ORF1b, ORF2a, ORF2b, ORF3-ORF7, 3' UTR) that can be independently analyzed and modified. This segmentation facilitates systematic study of viral functions while maintaining overall viral integrity for infection studies.
Solution Approach 2:
The patent uses cell culture systems as intermediaries to produce the infectious virus from the synthetic cDNA. The cDNA is transcribed in vitro to produce viral RNA, which is then introduced into permissive cell lines (such as MA-104 or MARC-145 cells) to enable viral replication and production of infectious particles. This intermediary approach simplifies the overall system by using well-characterized cell models.
3Adaptability or versatility
If attenuated strains are developed from the infectious clone, then vaccine development is improved, but the time required for strain attenuation and characterization increases
Solution Approach 1:
The patent performs preliminary actions by creating the infectious cDNA clone with known mutations before beginning attenuation studies. The synthetic clone includes pre-introduced mutations (such as those in the nsp1 gene) that can be further modified to create attenuated strains. This preliminary preparation of the genetic framework accelerates subsequent attenuation work by eliminating the need to generate the base clone from scratch.
Solution Approach 2:
The patent employs parameter changes in the viral genome to create attenuated strains suitable for vaccine development. Specific mutations are introduced at defined positions (e.g., in the nsp1 gene at positions 181, 623, 1561) to reduce viral virulence while maintaining replication capability. These controlled parameter changes enable the creation of live attenuated vaccines with predictable characteristics.
Data Source
AI summary
The present invention belongs to the field of animal health and relates to a nucleic acid sequence which comprises the genome of an infectious genotype I (EU) PRRS virus clone useful for studying Porcine Reproductive and Respiratory Syndrome (PRRS), a viral disease affecting swine, and in the development of vaccines, therapeutics and diagnostics for the prophylaxis, treatment and diagnosis of PRRS.