Simian Adenoviral Vectors With Dual Expression Cassettes
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Solution Overview
Problem
Human adenoviruses have high seroprevalence, leading to pre-existing immunity issues, limiting their effectiveness in gene therapy and vaccine applications, while human adenoviral vectors face challenges in delivering molecules to target cells effectively due to this immunity.
Innovation Solution
Development of simian adenoviral vectors, such as chimpanzee adenoviruses, with two expression cassettes, where one is inserted in the E1 region and the other in a region compatible with vector replication, such as HE1 or HE2, enhancing cloning capacity and minimizing seroprevalence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If human adenoviral vectors are used for gene transfer, then high transgene capacity and efficient gene transfer are achieved, but pre-existing immunity significantly reduces effectiveness
Solution Approach 1:
The patent uses simian adenovirus as an intermediary vector that bridges the gap between human adenovirus advantages (large capacity, efficient transfer) and the need to avoid pre-existing immunity. The simian adenovirus serves as a mediator that can deliver human transgenes effectively without triggering pre-existing human anti-adenovirus immunity, thus resolving the contradiction between transfer efficiency and reliability.
2Reliability
If E1 region is replaced with transgene cassette for replication defective virus, then safety is improved, but cloning capacity is limited
Solution Approach 1:
The patent segments the adenovirus genome into multiple independent expression cassettes located in different regions (E1 region and HE1 or HE2 regions). This segmentation allows the virus to maintain replication defectiveness (safety) while providing multiple separate cloning sites that can accommodate different transgenes, thereby increasing overall cloning capacity without compromising safety.
3Reliability
If simian adenovirus is used instead of human adenovirus, then pre-existing immunity is minimized, but cloning capacity and expression flexibility are reduced
Solution Approach 1:
The patent makes the simian adenovirus vector universal by incorporating multiple expression cassettes that can accommodate different transgenes with various promoters and regulatory elements. The vector system can now perform multiple functions: maintaining low seroprevalence advantage, providing expanded cloning capacity through multiple insertion sites, and offering expression flexibility through different promoter choices in each cassette, thus achieving multi-functionality that resolves the previous limitations.
Data Source
AI summary
A simian adenoviral vector comprising two expression cassettes, wherein each expression cassette comprises a transgene and a promoter, and wherein the first expression cassette is inserted in the E1 region of the simian adenoviral vector, and the second expression cassette is inserted in a region of the adenoviral vector that is compatible with vector replication.