Genetically Stable Live Attenuated RSV Vaccine Through L-Protein Mutations
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Solution Overview
Problem
Existing live-attenuated respiratory syncytial virus (RSV) vaccines face challenges such as genetic instability, difficulty in attenuation, and the need for improved immunogenicity and stability, which are compounded by the virus's limited replication in cell culture and inefficiency in experimental animals.
Innovation Solution
Development of recombinant RSV strains with specific mutations at codons 1321, 1313, and other positions in the L protein, combined with deletions and temperature-sensitive characteristics, to enhance genetic and phenotypic stability and attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional biologically-derived RSV vaccine candidates are used, then vaccine development can proceed using traditional methods, but the candidates exhibit genetic instability and under-attenuation or over-attenuation
Solution Approach 1:
The patent applies parameter changes by systematically modifying codons at specific positions (1321, 1313, 1316) in the L protein gene to create stable attenuated mutations. Different codons encoding the same amino acids are tested to identify combinations that provide both attenuation and genetic stability, resolving the contradiction between achieving attenuation and maintaining stability.
Solution Approach 2:
The patent segments the attenuation problem into specific codon positions (1321, 1313, 1316) within the L protein gene. By focusing mutations at these discrete locations rather than using random or conventional attenuation methods, the patent achieves precise control over both attenuation level and genetic stability.
2Object-affected harmful factors
If attenuating mutations are introduced to reduce virus replication, then vaccine safety improves, but immunogenicity is reduced
Solution Approach 1:
The patent changes the attenuation parameter by selecting specific codon substitutions at positions 1321, 1313, and 1316 that provide moderate attenuation. This allows the virus to replicate sufficiently to induce immunity while still being safe, resolving the contradiction between safety and immunogenicity.
Solution Approach 2:
The patent applies partial attenuation rather than complete inhibition of virus replication. By using codon substitutions that reduce but do not eliminate replication, the patent maintains sufficient viral activity to stimulate immune response while ensuring safety.
3Productivity
If RSV is grown in cell culture for vaccine production, then vaccine manufacturing can proceed, but the virus grows only to moderate titers and is present in long filaments that are difficult to purify
Solution Approach 1:
The patent changes viral growth parameters by using recombinant RSV strains with specific L protein mutations. These mutations appear to improve virus growth characteristics in cell culture, increasing titers and reducing filament formation, thereby facilitating easier purification while maintaining productivity.
4Adaptability or versatility
If RSV is used in experimental animals for testing, then preclinical evaluation can be performed, but the virus replicates inefficiently in most experimental animals
Solution Approach 1:
The patent changes the viral parameters through recombinant engineering with specific codon substitutions. These changes appear to enhance the virus's ability to replicate in experimental animals, improving preclinical testing capabilities while maintaining the attenuated phenotype for safety.
Data Source
Figure 1A~1F
Figure 2
Figure 3A~3B
AI summary
Provided herein are recombinant respiratory syncytial viruses that contain mutations that make the disclosed viruses attractive vaccine candidates. The viruses disclosed contain attenuating mutations designed to have increased genetic and phenotypic stability. Desired combinations of these mutations can be made to achieve desired levels of attenation. Exemplary vaccine candidates are described. Also provided are polynucleotides capable of encoding the described viruses, as wells as methods for producing the viruses and methods of use.