Single Expression Vector for Stable Antibody Production in Cereal Endosperm
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Solution Overview
Problem
Current methods for producing recombinant antibodies in plants face challenges such as low yield, complex selection procedures, and instability due to gene silencing phenomena, making it difficult to achieve high and equimolar expression of light and heavy chains in cereal endosperm for industrial-scale production.
Innovation Solution
A single expression vector is used that integrates operatively linked expression cassettes for both light and heavy chains with identical regulatory elements, including an endosperm-specific promoter, leader sequence, and terminator, to ensure coordinated expression and stable production of whole recombinant antibodies in cereal endosperm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If separate expression cassettes with different regulatory elements are used for light and heavy chains, then each chain can be expressed independently, but the production process becomes complex and yields are low
Solution Approach 1:
The patent combines separate expression cassettes for light and heavy chains into a single integrated expression cassette. This unified cassette contains both coding sequences under the control of a single promoter (such as the endosperm-specific GluB-4 promoter), eliminating the need for separate transformation and selection procedures. The merging approach directly increases antibody yield by ensuring coordinated expression of both chains while simplifying the production process to a single transformation event.
Solution Approach 2:
The single expression cassette serves multiple functions simultaneously: it drives expression of both light and heavy chains, ensures their proper stoichiometric balance, and simplifies selection procedures. The universal promoter system controls both chains, making the system more efficient and reducing the number of separate operational steps required in traditional methods.
2Loss of time
If traditional co-transformation methods are used, then both chains can be introduced, but selection procedures become complex and time-consuming
Solution Approach 1:
The patent merges the introduction of light and heavy chain genes into a single transformation event using one expression cassette. This eliminates the need for sequential co-transformation and multiple selection steps. The single cassette approach reduces selection procedure time dramatically while maintaining ease of operation, as only one transformation and one selection process are required instead of multiple separate operations.
3Reliability
If repeated DNA sequences are used to increase expression, then production levels may increase, but gene silencing phenomena occur causing instability
Solution Approach 1:
The patent changes the structural parameters of the expression cassette by using a single copy design with optimized regulatory elements instead of repeated sequences. The endosperm-specific promoter and other control elements are engineered to achieve high expression levels from a single cassette, eliminating gene silencing phenomena. This parameter change maintains reliability through stable single-copy integration while achieving high productivity through optimized promoter strength and tissue-specific expression.
4Ease of manufacture
If CHO cell systems are used for antibody production, then correctly assembled antibodies with human-compatible glycosylation are obtained, but investment and operating costs are high
Solution Approach 1:
The patent employs a plant-based expression system (cereal endosperm) as a cheaper alternative to expensive CHO cell cultures. The single expression cassette is designed to function efficiently in plant cells, utilizing plant-specific regulatory elements like the endosperm-specific promoter. This approach dramatically reduces investment and operating costs while maintaining manufacturing precision through the coordinated expression design that ensures proper antibody assembly and human-compatible glycosylation patterns.
Data Source
AI summary
Expression vector for the stable production of a protein in plants, in particular a whole recombinant antibody in a cereal endosperm, comprising an expression cassette for the light polypeptide chain (L) of the antibody and an expression cassette for the heavy polypeptide chain (H) of the antibody, having the same orientation and the same control and regulatory elements of gene expression.