Recombinant HVT Vectors for Avian Vaccine Interference
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Solution Overview
Problem
Current recombinant avian viral vector vaccines, particularly those based on HVT, often exhibit interference when used in combination, leading to reduced protection against multiple avian pathogens, necessitating a solution for enhancing their efficacy and stability for simultaneous protection against Newcastle disease, infectious bursal disease, and other avian infections.
Innovation Solution
Development of polyvalent compositions comprising recombinant HVT vectors with heterologous polynucleotides expressing avian pathogen antigens, combined with SB1 vectors, utilizing optimized promoters, codon-optimized genes, and polyA tails to enhance expression and stability, thereby avoiding interference and improving immunogenic response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple HVT recombinant vaccines expressing different antigens are used together, then broader pathogen coverage is achieved, but interference occurs leading to reduced protection
Solution Approach 1:
The patent divides the vaccination system into distinct viral vector types (HVT and SB1) with different genetic backbones. By segmenting the vaccine components into separate viral vectors rather than combining multiple antigens in a single HVT vector, the interference problem is avoided while maintaining broad pathogen coverage through complementary antigen expression.
Solution Approach 2:
The patent combines HVT and SB1 viral vectors in a polyvalent composition to achieve synergistic effects. This merging of different viral vector systems allows simultaneous delivery of multiple antigens without the interference that occurs when multiple antigens are expressed from the same HVT backbone, thereby improving overall protection efficacy.
2Adaptability or versatility
If HVT vectors are used to express multiple protective genes, then multivalent protection is achieved, but stability and efficacy are reduced due to interference
Solution Approach 1:
The patent segments the multivalent vaccine into separate HVT and SB1 viral vectors, each expressing specific antigens. This segmentation prevents the genetic and immunological interference that would occur if multiple protective genes were expressed from a single HVT vector, thereby maintaining vaccine stability and composition integrity.
Solution Approach 2:
The patent uses SB1 viral vectors as intermediaries to deliver certain antigens that would otherwise interfere with HVT vector stability. By using SB1 as a mediator vector with different genetic characteristics, the system achieves multivalent protection while maintaining the stability of each individual vector component.
3Reliability
If recombinant avian viral vectors are used for vaccination, then protection against avian pathogens is achieved, but variable levels of protection occur
Solution Approach 1:
The patent optimizes key parameters of the viral vectors including promoter strength, antigen gene sequences, and polyA tail configurations. By systematically adjusting these parameters in HVT and SB1 vectors, the patent achieves consistent and reliable protection levels across different vaccine compositions, eliminating the variability observed in previous recombinant viral vector vaccines.
Data Source
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AI summary
The present invention provides recombinant herpesvirus of turkeys (HVT) vectors that contain and express antigens of avian pathogens, compositions comprising the recombinant HVT vectors, polyvalent vaccines comprising the recombinant HVT vectors and one or more wild type viruses or recombinant vectors. The present invention further provides methods of vaccination against a variety of avian pathogens and method of producing the recombinant HVT vectors.