PRRSV N Protein Epitope Marker for DIVA Vaccine Differentiation
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Solution Overview
Problem
Current PRRSV vaccines struggle to distinguish between naturally infected animals and those immunized with a whole-virus vaccine, leading to challenges in infection status evaluation and herd purification, with attenuated vaccines posing safety risks and inactivated vaccines offering insufficient cross-immune protection.
Innovation Solution
Development of an N protein epitope deletion-marked vaccine strain of type II PRRSV with specific amino acid mutations at positions 92 to 103, utilizing a porcine single B cell antibody C8 for differentiation, and a competitive ELISA kit for accurate identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If attenuated vaccines are used for PRRSV control, then immune protection is provided, but safety issues arise including reversion to virulence and recombination with field strains
Solution Approach 1:
The patent extracts a specific epitope (amino acid residue 92-103 of N protein) from the viral structure and deletes it to create a safe vaccine strain that cannot revert to virulence, while maintaining other protective antigens for immune protection
Solution Approach 2:
The patent applies local quality by making a targeted deletion at a specific location (N protein epitope region) rather than altering the entire virus, creating a localized modification that ensures safety while preserving overall immunogenicity
2Reliability
If inactivated vaccines are used for PRRSV control, then safety is improved, but cross-immune protection against heterologous pandemic strains is insufficient
Solution Approach 1:
The patent changes the physical state parameter from inactivated (killed) to attenuated (live but weakened) vaccine form, while simultaneously modifying the genetic parameter by deleting a specific epitope to ensure safety and prevent reversion
3Measurement precision
If epitope deletion is performed to enable differentiation between vaccinated and infected animals, then detection capability is improved, but immunogenicity may be reduced leading to reduced immune efficacy
Solution Approach 1:
The patent removes only a specific non-neutralizing epitope (amino acid residue 92-103 of N protein) from the viral structure, leaving all other immunogenic regions intact to maintain strong immune protection while enabling detection differentiation
Solution Approach 2:
The patent applies local quality by targeting a specific non-critical epitope region for deletion, preserving the overall immunogenicity of the virus while creating a detectable marker for vaccine-administered animals
Data Source
AI summary
The present disclosure provides an N protein epitope mutation marker for preparing an epitope deletion-marked vaccine strain of type II porcine reproductive and respiratory syndrome virus (PRRSV) and use thereof, belonging to the technical field of biological products. In the mutation marker, one or more amino acids are mutated based on an epitope sequence at positions 92 to 103 of a C-terminal of an N protein of the type II PRRSV; and the epitope mutation marker has an amino acid sequence shown in SEQ ID NO: 1, where X1 is selected from the group consisting of T, P, and A; and X2 is selected from the group consisting of V and A.