Engineered Shigella Outer Membrane Vesicles for Broad Serotype Coverage
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Solution Overview
Problem
Existing Shigella vaccines face challenges in providing broad protection against multiple serotypes due to serotype replacement and the complexity of serotype prevalence, especially in Low- and Middle-Income Countries, and current methods are inefficient in quickly producing vaccines against a range of Shigella strains.
Innovation Solution
The use of complementing plasmids containing genes that modify Shigella O-antigen enzymes, such as gtrI, gtrII, gtrIV, gtrV, gtrX, and oacA, to engineer Shigella bacteria to express modified O-antigens, allowing for the production of outer membrane vesicles that include epitopes from multiple serotypes, thereby enhancing vaccine coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If vaccines are developed against a small number of Shigella strains, then vaccine development is simpler and more affordable, but serotype replacement occurs and protection against multiple serotypes is insufficient
Solution Approach 1:
The patent applies universality by creating a single vaccine platform that can protect against multiple Shigella serotypes through enzymatic modification of O-antigen. The recombinant bacterium expresses multiple O-antigen variants simultaneously, enabling one vaccine formulation to provide broad serotype coverage rather than requiring separate vaccines for each serotype.
Solution Approach 2:
The patent utilizes parameter changes by modifying the chemical structure of O-antigen through enzymatic actions (glucosylation, acetylation). These chemical modifications create distinct epitopic patterns that recognize different serotypes, allowing the same bacterial platform to generate multiple serotype-specific antigens through controlled biochemical parameter changes.
2Productivity
If traditional methods are used to produce vaccines against multiple Shigella strains, then vaccine effectiveness is achieved, but production time and efficiency are reduced
Solution Approach 1:
The patent applies preliminary action by pre-engineering the recombinant Shigella bacterium with plasmids containing multiple O-antigen modification enzymes before vaccine production. This preliminary genetic engineering allows the bacterium to spontaneously produce multiple O-antigen variants during standard cultivation, eliminating the need for separate viral attack and purification steps for each serotype.
Solution Approach 2:
The recombinant bacterium performs self-service by spontaneously generating multiple O-antigen variants through its own enzymatic machinery during normal growth. The engineered enzymes (GtrI, GtrII, GtrIV, GtrV, GtrX, OacA) modify the O-antigen in real-time during bacterial replication, eliminating the need for external enzymatic treatment steps.
3Adaptability or versatility
If enzymes GtrI, GtrII, GtrIV, GtrV, GtrX and OacA are used to modify O-antigen, then multiple serotype epitopes are generated, but the complexity of enzymatic modification increases
Solution Approach 1:
The patent merges multiple enzymatic functions into a single bacterial expression system. By co-expressing multiple O-antigen modification enzymes (GtrI, GtrII, GtrIV, GtrV, GtrX, OacA) in one recombinant bacterium, the system combines what would otherwise be separate enzymatic processes into a unified metabolic pathway that generates multiple O-antigen variants simultaneously.
Solution Approach 2:
The recombinant Shigella bacterium serves as an intermediary platform that houses and coordinates multiple O-antigen modification enzymes. The bacterial cell provides the metabolic intermediates and structural framework needed for enzyme function, while the plasmid-based expression system coordinates enzyme production and O-antigen modification in an integrated manner.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the rapid and efficient production of vaccines that protect against a variety of Shigella serotypes by incorporating modified O-antigens, offering broader immunity and overcoming the limitations of existing vaccines.
Implementation Method 1
enzymes GtrI, GtrII, GtrIV, GrtrV, GtrX and OacA are involved in establishing the glucosylation and acetylation patterns on S. flexneri O-antigen
Implementation Method 2
enzymes GtrI, GtrII, GtrIV, GrtrV, GtrX and OacA are involved in establishing the glucosylation and acetylation patterns on S. flexneri O-antigen
Implementation Method 3
providing complementing plasmids comprising genes encoding one or more of enzymes that modify a Shigella O-antigen can be used to grow Shigella bacteria comprising O-antigen having modified glucosylation and acetylation patterns
Implementation Method 4
Gram-negative bacteria spontaneously release exosomes from their outer membrane, also called Outer Membrane Vesicles (OMV), containing surface exposed antigens in their native environment together with immuno-stimulatory molecules
Data Source
AI summary
The present invention relates to Shigella outer membrane vesicles comprising at least one heterologous O-antigen, a recombinant Shigella bacterium comprising at least one heterologous O-antigen, methods for preparing the outer membrane vesicles or recombinant Shigella bacterium, plasmids for use in the methods, immunogenic compositions, vaccines and methods of treatment.