Auxotrophic E. Coli Vaccine Strain for Stable APEC Immunity
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Solution Overview
Problem
Existing vaccines for avian pathogenic E. coli (APEC) face challenges in achieving effective immunogenicity while maintaining metabolic deficiency, niche persistence, and stability in complex microbiota environments, with risks of reversion to virulence and adverse immune responses.
Innovation Solution
Development of a live attenuated E. coli vaccine strain with mutations in alr, asd, metC, and dadX genes, ensuring metabolic auxotrophy and immunogenicity, while preventing reversion and minimizing adverse effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a live attenuated E. coli vaccine strain is used to induce robust immune responses, then immunogenicity is improved, but there is a risk that the strain may revert to virulence and cause disease
Solution Approach 1:
The patent extracts and removes the virulence factors from the E. coli strain while preserving the immunogenic components. By deleting specific virulence genes (such as those encoding adhesins, invasins, or toxins) while retaining genes that stimulate immune responses, the vaccine strain becomes attenuated (non-pathogenic) but remains immunogenic, thus resolving the contradiction between inducing immune responses and preventing disease causation
Solution Approach 2:
The patent changes the genetic parameters of the E. coli strain by introducing specific mutations or deletions in virulence genes. This parameter change (genetic modification) reduces the virulence of the bacteria while maintaining their ability to stimulate the immune system, thereby allowing the strain to be used safely as a live attenuated vaccine
2Stability of the object's composition
If metabolic auxotrophy is introduced to prevent reversion to virulence, then stability is improved, but the strain's ability to persist in the host is reduced
Solution Approach 1:
The patent introduces an intermediary mechanism where the auxotrophic strain depends on specific nutrients provided by the host's microbiota or environment. This intermediary nutritional dependency ensures the strain remains stable and attenuated (cannot revert to virulence) while still allowing it to persist in the host by exploiting available nutritional niches, thus resolving the contradiction between stability and persistence
3Reliability
If multiple gene deletions are made to ensure metabolic deficiency and prevent reversion, then reliability is improved, but the complexity of vaccine development increases
Solution Approach 1:
The patent segments the genome modification process into distinct, manageable steps. Instead of making multiple complex deletions simultaneously, the approach divides the attenuation process into sequential gene deletions or targeted mutations, each verified for stability and safety. This segmentation reduces development complexity while maintaining reliability through systematic validation of each genetic modification
Data Source
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Figure 3A
AI summary
The present invention relates to live attenuated bacteria which persist in a subject and their use in vaccine compositions. In particular, the invention is directed to mutant strain E .coli vaccines which are useful for poultry, and especially chickens.