Modified Pseudomonas Exotoxin A Reducing Immunogenicity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pseudomonas exotoxin A (PE) is highly immunogenic, leading to an immune response that neutralizes its cytotoxic activity, reducing its effectiveness in treating diseases like cancer due to the stimulation of anti-PE antibodies and immune cells, which limits the amount that can be administered.
Innovation Solution
Modification of the PE amino acid sequence by substituting specific residues, such as E420, D463, Y481, L516, R563, D581, and K606, and optionally deleting or further modifying T-cell and B-cell epitopes, along with incorporating a furin cleavage sequence, to reduce immunogenicity while maintaining cytotoxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PE is administered to treat cancer, then cytotoxic activity is achieved, but immunogenicity increases leading to neutralization by anti-PE antibodies
Solution Approach 1:
The patent applies parameter changes by substituting specific amino acid residues in the PE sequence (e.g., positions 420, 463, 481, 516, 563, 581, 589, 606) to alter the protein's immunogenic properties while preserving its cytotoxic function. This modifies the chemical parameters of the toxin to reduce immune recognition.
Solution Approach 2:
The patent extracts and removes specific epitopic regions from the PE molecule that are responsible for triggering the immune response. By deleting or modifying these specific amino acid sequences, the harmful immunogenic components are separated from the beneficial cytotoxic components.
2Object-generated harmful factors
If PE is modified to reduce immunogenicity, then immune response is reduced, but cytotoxic activity may be compromised
Solution Approach 1:
The patent applies local quality by making targeted modifications only at specific locations (amino acid positions) within the PE molecule that are responsible for immunogenicity, while leaving the critical cytotoxic domains intact. This localized approach ensures that immune response is reduced without compromising the toxin's ability to kill cancer cells.
Solution Approach 2:
The patent carefully selects which amino acid parameters to change (those in epitopic regions) and which to preserve (those critical for cytotoxic function), thereby altering immunogenicity parameters while maintaining cytotoxicity parameters at effective levels.
3Productivity
If higher doses of PE are administered to overcome neutralization, then therapeutic effectiveness increases, but immune response intensity increases
Solution Approach 1:
The patent converts the harmful immunogenicity of PE into a beneficial property by modifying the molecule so that it elicits reduced immune response. The very feature that caused harm (immunogenicity) is transformed through amino acid substitution into a benefit (reduced neutralization), allowing higher effective doses to be administered without proportional increases in immune response.
Data Source
AI summary
The invention provides a Pseudomonas exotoxin A (PE) comprising an amino acid sequence having a substitution of one or more of amino acid residues E420, D463, Y481, L516, R563, D581, D589, and K606, wherein the amino acid residues are defined by reference to SEQ ID NO: 1. The invention further provides related chimeric molecules, as well as related nucleic acids, recombinant expression vectors, host cells, populations of cells, and pharmaceutical compositions. Methods of treating or preventing cancer in a mammal, methods of inhibiting the growth of a target cell, methods of producing the PE, and methods of producing the chimeric molecule are further provided by the invention.