Site-Specific PEGylated IL-2 Mutants for Treg Selectivity
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Solution Overview
Problem
Existing IL-2 mutants face challenges in achieving improved preference for Treg cells, prolonged half-life, and reduced activation of Teff cells and NK cells, leading to suboptimal therapeutic effects in autoimmune diseases.
Innovation Solution
Development of site-specific PEGylated IL-2 mutants with targeted amino acid modifications, such as N33C, S75C, N77C, D84C, N88C, N88R, D109C, and V91C, to enhance binding to IL-2Rαβγ, reduce IL-2Rβγ affinity, and prolong half-life, thereby selectively activating Treg cells while minimizing activation of Teff cells and NK cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If IL-2 mutants are prepared to change receptor preference, then preference for Treg cells is improved, but half-life is shortened
Solution Approach 1:
The patent combines two separate modification strategies: (1) amino acid mutations (N88R, N77C) to change receptor preference, and (2) PEGylation to extend half-life. The PEG molecule is site-specifically conjugated to the mutant IL-2 protein, merging the benefits of both modifications in a single therapeutic agent.
Solution Approach 2:
The PEG molecule acts as an intermediary that extends the circulation half-life of the IL-2 mutant without interfering with its receptor binding properties. The site-specific conjugation at the N77C position ensures the PEG does not block the functional sites while providing the desired pharmacokinetic improvement.
2Adaptability or versatility
If multiple site mutations are introduced to improve Treg cell preference, then receptor affinity is improved, but immunogenicity increases
Solution Approach 1:
The patent introduces mutations at specific local positions (N88R, N77C) that are strategically chosen to affect receptor binding properties without causing extensive changes to the overall protein structure. This localized modification approach minimizes immunogenicity while achieving the desired functional change.
Solution Approach 2:
The patent carefully selects amino acid substitutions that change the binding parameters (affinity and specificity) for different IL-2 receptors. The N88R mutation increases affinity for the high-affinity receptor (IL-2Rαβγ) while the N77C mutation, when PEGylated, further modulates the binding characteristics to achieve selective Treg cell activation.
3Duration of action of stationary object
If PEGylation is applied to extend half-life, then duration of action is improved, but activation of Teff cells and NK cells is not sufficiently reduced
Solution Approach 1:
The patent merges the half-life extension effect of PEGylation with the cell-type selectivity effect of the N88R and N77C mutations. The combination achieves both prolonged circulation and selective Treg cell activation, as the mutations specifically alter binding to different IL-2 receptor subtypes while PEGylation maintains the modified protein in circulation longer.
4Duration of action of stationary object
If site-specific PEGylation is performed, then half-life is prolonged, but manufacturing complexity increases
Solution Approach 1:
The engineered cysteine residue at position 77 (N77C) serves as a specific intermediary target for PEGylation. This site-specific cysteine provides a unique reaction site that enables selective conjugation, simplifying the manufacturing process compared to non-specific PEGylation methods while still achieving the desired half-life extension.
Data Source
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AI summary
Provided is a site-specific PEG-modified interleukin 2 (IL-2) mutant. Compared with a parent IL-2, the mutant has an improved preference for a Treg cell and a prolonged half-life period. Also provided are a composition comprising the IL-2 mutant, a nucleic acid encoding the IL-2 mutant, a vector comprising the nucleic acid, and a host cell. Further provided are the IL-2 mutant and therapeutic use of a pharmaceutical composition comprising same.