IL21 Mutant Disulfide Bond Stabilization for Tumor Immunotherapy
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Solution Overview
Problem
The short plasma half-life of IL21 limits its therapeutic efficacy in tumor immunotherapy due to rapid degradation and low druggability, leading to systemic toxic reactions and limited clinical application.
Innovation Solution
Development of IL21 protein mutants with specific amino acid substitutions and disulfide bond formations, such as ILE to CYS at position 16 and SER to CYS at position 70, to stabilize the protein conformation and enhance its biological activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If IL21 is administered systemically to achieve therapeutic effect, then anti-tumor immune response is enhanced, but plasma half-life is short leading to rapid degradation and systemic toxicity
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of IL21 through site-directed mutagenesis. Specific residues (e.g., Lysine at position 10 to Glutamic acid, Arginine at position 13 to Glutamic acid) are mutated to alter the protein's physical-chemical parameters such as charge distribution and hydrophobicity, which in turn improve plasma half-life and stability without compromising biological activity
Solution Approach 2:
The patent applies local quality by making targeted local modifications at specific positions within the IL21 molecule rather than global changes. The mutations are strategically placed at surface-exposed residues that do not interfere with the core functional regions, allowing local optimization of stability and half-life while preserving the overall structure and function
2Reliability
If IL21 dose is increased to overcome short half-life, then therapeutic effect may be improved, but systemic toxic reactions increase
Solution Approach 1:
The patent changes the kinetic and stability parameters of IL21 through amino acid mutations, extending plasma half-life from approximately 3 hours to significantly longer durations. This allows therapeutic effect to be maintained at lower doses, thereby reducing systemic toxicity
Solution Approach 2:
The patent converts the harmful rapid clearance and short half-life into a beneficial extended circulation and sustained activity by introducing mutations that improve protein stability. The original limitation (short half-life) is transformed into an advantage (prolonged therapeutic action at lower doses)
3Reliability
If IL21 is used to activate immune cells, then anti-tumor response is enhanced, but druggability is limited due to rapid degradation
Solution Approach 1:
The patent improves druggability by changing the stability parameters of IL21 through rational design of amino acid mutations. The modified IL21 exhibits improved resistance to proteolytic degradation and enhanced plasma stability, making it more suitable for therapeutic development and administration
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 IL21 mutants exhibit improved thermal stability, prolonged plasma half-life, and enhanced biological activity, reducing systemic toxicity and increasing the therapeutic window for tumor immunotherapy.
Implementation Method 1
with ILE at position 16 and SER at position 70 of the amino acid sequence of the wild-type IL21 both mutating into CYS, and a disulfide bond forming between the two mutated CYSs
Data Source
AI summary
The invention relates to an interleukin-21 protein (IL21) mutant and application thereof. The mutant is with ILE at position 16 and SER at position 70 of the amino acid sequence of the wild-type IL21 both mutating into CYS, and a disulfide bond forming between the two mutated CYSs. The amino acid sequence of the wild-type IL21 is shown in SEQ ID NO. 1. The invention also relates to a fusion protein containing the IL21 mutant protein and a use of the IL21 mutant protein or the fusion protein in the preparation of a medicine and, preferably, the medicine regulates or activates immunity or are an anti-tumor medicine. The invention also relates to the use of the IL21 mutant, the IL21/4 mutant or the fusion protein in the preparation of a formulation for promoting the differentiation and proliferation of B cell, the differentiation and proliferation of T cell, the differentiation and proliferation of NK cell.