Fusion Immunotoxin Linker Design for High-Yield In Vitro Synthesis
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Solution Overview
Problem
Current immunotoxins face challenges in production cost, efficiency, and stability due to reliance on chemical conjugation and cellular expression systems, leading to low yield, high immunogenicity, and poor therapeutic efficacy.
Innovation Solution
A fusion protein is developed with a specific linker connecting an effector moiety and a targeting vector moiety, suitable for in vitro synthesis using a yeast cell extract, enabling high-yield production and maintaining therapeutic activity comparable to commercial products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chemical conjugation is used to link toxin proteins to antibodies, then immunotoxins can be produced, but conjugation efficiency is low, production costs are high, and product homogeneity is poor
Solution Approach 1:
The patent replaces chemical conjugation methods with recombinant genetic engineering to produce immunotoxins. Instead of using chemical reagents to link toxin proteins to antibodies, the invention uses genetic fusion to create a single polypeptide chain containing both the targeting moiety and effector moiety connected by a peptide linker. This substitution eliminates the problems of low conjugation efficiency, high costs, and poor homogeneity associated with chemical methods.
2Reliability
If intact monoclonal antibody molecules are used in immunotoxins, then specificity and stability are maintained, but molecules are too large to penetrate tissues effectively and immunogenicity is high
Solution Approach 1:
The patent segments the intact monoclonal antibody into smaller functional units, specifically using antibody fragments (such as Fab, F(ab')2, or single-chain antibodies) as the targeting moiety instead of whole antibodies. This segmentation reduces the overall size of the immunotoxin molecule, improving tissue penetration while maintaining the specificity and stability provided by the antibody-derived targeting component.
3Length of moving object
If Fv fragment is used for immunotoxin construction, then molecular size is small and expression is easy, but structure is unstable and prone to dissociation
Solution Approach 1:
The patent merges the Fv fragment with a toxin effector moiety through a peptide linker to create a single-chain immunotoxin. This merging approach maintains the small size advantage of Fv fragments while stabilizing the structure through the covalent connection to the toxin component and the linker, preventing dissociation of the antigen-binding domains.
4Manufacturing precision
If cellular expression systems are used to produce recombinant immunotoxins, then product homogeneity and stability are improved, but production cost and time are high
Solution Approach 1:
The patent employs transient expression systems or cell-free protein synthesis as alternatives to permanent cellular expression systems. These approaches use disposable cell lines or in vitro systems that do not require long-term cell maintenance, extensive fermentation cycles, or complex downstream processing, thereby reducing both time and cost while still achieving homogeneous product through recombinant genetic engineering.
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
The fusion protein achieves high-yield, low-cost production with improved stability and activity, suitable for large-scale manufacturing and effective targeting of cancer cells.
Implementation Method 1
suitable for in vitro synthesis using a yeast cell extract
Data Source
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AI summary
Provided is a fusion protein, which can be produced at a low cost, in a short period, and with a high yield. Also provided are a coding nucleic acid of the fusion protein, an in-vitro synthesis system, a preparation method, and the like. The fusion protein has: an effector moiety A for killing a target cell, including a toxin molecule; a targeting vector moiety B that binds to a target site on the target cell, the targeting vector moiety being derived from an antibody or a cytokine; and a first linker L1 for linking the effector moiety A to the targeting vector moiety B, wherein the first linker L1 comprises at least 3 amino acid residues. Preferably, the linking mode of the effector moiety A, the first linker L1, and the targeting vector moiety B from the N-terminus to the C-terminus is A-L1-B or B-L1-A.