Human IL-2 PEG Conjugate With Site-Directed Oxime Coupling
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Solution Overview
Problem
Current modifications of interleukin 2 (IL-2) such as site-directed mutation, fusion expression, and PEGylation face challenges including reduced binding ability, immunogenic reactions, complicated production processes, and high costs, failing to effectively prolong the half-life and maintain biological activity.
Innovation Solution
A human interleukin 2-polyethylene glycol conjugate is developed by mutating natural amino acids with unnatural amino acids containing a carbonyl terminal group, allowing site-directed coupling through an oxime bond with PEG, thereby enhancing stability and binding specificity while prolonging the half-life of IL-2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If site-directed mutation is used to modify IL-2, then binding specificity can be improved, but binding ability with IL-2Rβγ may be reduced
Solution Approach 1:
The patent introduces unnatural amino acids as intermediaries between the IL-2 protein and PEG. These unnatural amino acids contain specific functional groups (aldehyde, ketone, or nitrile) that enable selective chemical coupling with PEG while preserving the natural amino acid sequence and binding properties of IL-2. This intermediary approach allows site-directed PEGylation without compromising IL-2Rβγ binding ability.
Solution Approach 2:
The patent applies PEGylation at specific local sites on the IL-2 molecule through site-directed incorporation of unnatural amino acids at predetermined positions (e.g., surface-exposed residues). This localized modification ensures that PEG attachment occurs away from critical binding interfaces, maintaining binding specificity while extending half-life.
2Duration of action of moving object
If PEGylation is used to prolong half-life, then duration of action is improved, but immunogenic reactions may increase
Solution Approach 1:
The unnatural amino acid serves as a chemical intermediary that facilitates gentle, site-specific coupling of PEG to IL-2. This controlled approach produces more homogeneous conjugates with consistent pharmacokinetic properties, reducing immunogenicity compared to random PEGylation methods.
Solution Approach 2:
The patent optimizes PEG parameters including molecular weight (e.g., 20-40 kDa), degree of substitution (typically 1-3 PEG chains per IL-2), and attachment site characteristics to achieve the desired balance between prolonged half-life and reduced immunogenicity. The site-directed approach ensures optimal PEG:IL-2 ratio and spatial distribution.
3Duration of action of moving object
If fusion expression is used to enhance stability, then half-life is prolonged, but device complexity increases
Solution Approach 1:
The patent extracts the PEGylation step from complex fusion expression systems and implements it as a separate, controlled chemical modification process using unnatural amino acids. This simplifies the overall production by using standard protein expression followed by a well-defined chemical coupling step, rather than requiring complex multi-component fusion proteins.
4Manufacturing precision
If site-directed PEGylation with unnatural amino acids is used, then coupling precision is improved, but manufacturing cost increases
Solution Approach 1:
The unnatural amino acid with reactive functional groups serves as a precise intermediary that enables site-directed PEG coupling. While the unnatural amino acid itself adds cost, this approach eliminates the need for complex purification and characterization required by random PEGylation, and ensures homogeneous product with consistent clinical performance.
Solution Approach 2:
The unnatural amino acid is incorporated into the IL-2 sequence during protein expression (via genetic code expansion or in vitro translation), performing the site-selection action in advance. This preliminary positioning of reactive groups allows subsequent PEG coupling to proceed efficiently with high precision and reduced manufacturing complexity.
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 conjugate retains IL-2Rβγ binding activity, inhibits Treg cell expansion, and significantly prolongs in vivo half-life, promoting CD8+ T cell activation and tumor inhibition with improved stability and coupling efficiency.
Implementation Method 1
the PEG is coupled to the at least one unnatural amino acid by forming an oxime bond between the carbonyl terminal group and the PEG containing a hydroxylamine terminal group
Data Source
AI summary
A human interleukin 2-polyethylene glycol conjugate and use thereof. The human interleukin 2-polyethylene glycol conjugate comprises a recombinant human interleukin 2 containing at least one unnatural amino acid and PEG coupled to the at least one unnatural amino acid. The unnatural amino acid is a compound containing a carbonyl terminal group and having a structure as shown in formula (I) or an enantiomer thereof, and the PEG is coupled to the at least one unnatural amino acid by forming an oxime bond between the carbonyl terminal group and the PEG containing a hydroxylamine terminal group. The human interleukin 2-polyethylene glycol conjugate can be used individually or in combination with other anti-tumor drugs for the treatment of diseases such as solid tumors and hematologic tumors.