IL-2 Selective Agonist Fusion Protein for Autoimmune Treatment
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Solution Overview
Problem
Current therapies for autoimmune diseases, such as those targeting regulatory T cells, face challenges including high toxicity, frequent administration, and lack of specificity, particularly with IL-2-based treatments which activate both Treg cells and other immune cells, leading to adverse effects.
Innovation Solution
Development of an IL-2 selective agonist fusion protein combining a modified IL-2 variant with an effector function-deficient IgG Fc protein and a linker peptide, designed to selectively activate high-affinity IL-2 receptors on Treg cells, thereby enhancing their numbers and function while minimizing systemic toxicity and frequency of administration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If IL-2-based treatments are used to activate Treg cells, then Treg cell activation is improved, but systemic toxicity increases due to activation of other immune cells
Solution Approach 1:
The patent applies local quality by creating an IL-2 variant with altered amino acid sequence that changes its binding specificity. The variant selectively binds to the high-affinity IL-2 receptor (IL-2Rαβγ) expressed on Treg cells while having reduced affinity for the intermediate-affinity receptor (IL-2Rβγ) on other immune cells. This localized modification of binding properties achieves selective Treg activation without broad immune system activation, thereby reducing systemic toxicity.
Solution Approach 2:
The patent employs parameter changes by modifying the amino acid sequence of IL-2 (specifically substitutions at positions 8, 12, and/or 125) to alter its pharmacological parameters. These sequence changes modify the receptor binding affinity profile, creating a variant with high selectivity for Treg cells. The parameter modification transforms IL-2 from a broad-acting immune stimulator into a selective Treg activator, improving the therapeutic index.
2Quantity of substance
If conventional IL-2 therapy is administered to increase Treg cell numbers, then Treg cell expansion is achieved, but administration frequency must be high
Solution Approach 1:
The patent applies self-service by designing the IL-2 variant to be self-amplifying through selective Treg activation. Once administered, the variant preferentially stimulates Treg cell proliferation and survival, leading to an expanding Treg population that continues to suppress autoimmune responses. The selective activation creates a self-sustaining therapeutic effect that reduces the need for frequent re-administration compared to conventional IL-2 therapy.
3Adaptability or versatility
If non-selective immune cell activation is used to treat autoimmune diseases, then broad immune stimulation is achieved, but specificity for Treg cells is reduced
Solution Approach 1:
The patent applies local quality by introducing specific amino acid substitutions in the IL-2 molecule that create a localized change in receptor binding interface. This localized modification enables the IL-2 variant to distinguish between different IL-2 receptor isoforms, achieving high specificity for Treg cells while maintaining the ability to activate the immune system when needed.
Solution Approach 2:
The patent employs parameter changes by altering the molecular parameters of IL-2 through amino acid sequence modification. These changes adjust the binding affinity parameters to create a steep selectivity curve between Treg cells (high-affinity receptor) and other immune cells (intermediate-affinity receptor), achieving precise targeting while preserving immune adaptability.
Data Source
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AI summary
This invention provides for a fusion protein between an IL2αβγ Selective Agonist protein (IL2 Selective Agonist) and a IgG Fc protein. The IL2 Selective Agonist moiety provides a therapeutic activity by selectively activating the IL2αβγ form of the receptor, thus selectively stimulating Tregs. The Fc moiety provides a prolonged circulating half-life compared to the circulating half-life of IL-2 or an IL2SA protein.