PD-1 IL-2 Immunoconjugates for Selective T Cell Activation
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Solution Overview
Problem
Existing IL-2 immunotherapy faces challenges such as toxicity from vascular leak syndrome, tumor tolerance due to activation-induced cell death, and immunosuppression by regulatory T cells, along with limitations in targeting tumor cells effectively.
Innovation Solution
A mutant IL-2 polypeptide conjugated to an antibody that binds to PD-1, specifically with amino acid substitutions F42A, Y45A, L72G, and Q126T, targets cytotoxic T lymphocytes and reverses PD-1 mediated immune suppression, enhancing anti-tumor efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wild-type IL-2 is used for immunotherapy, then anti-tumor efficacy is improved through T cell activation, but toxicity from vascular leak syndrome and immunosuppression by regulatory T cells increases
Solution Approach 1:
The patent applies local quality by creating mutant IL-2 variants with specific amino acid substitutions (e.g., F42A, Y45A, L72G, Q126T) that selectively alter binding affinity to different IL-2 receptor subunits. These mutations locally modify the IL-2 molecule's interaction properties to preferentially engage intermediate-affinity receptors on effector T cells while reducing binding to high-affinity receptors on regulatory T cells, thereby achieving differential biological effects that enhance anti-tumor activity while reducing immunosuppression and toxicity
Solution Approach 2:
The patent employs parameter changes by systematically varying the amino acid sequence of IL-2 to modify its receptor binding characteristics. Specific substitutions at positions 42, 45, 72, and 126 alter the molecular parameters of IL-2, changing its affinity profile across different receptor forms. This parameter modification transforms the biological response profile, shifting from the wild-type pattern of strong Treg activation to a modified pattern that favors effector T cell activation with reduced Treg-mediated immunosuppression
2Adaptability or versatility
If IL-2 targets all IL-2R expressing cells, then broad immune activation occurs, but preferential activation of cytotoxic T lymphocytes over regulatory T cells is not achieved
Solution Approach 1:
The mutant IL-2 molecules exhibit local quality in their receptor interaction profile, with specific mutations creating a biased binding preference. The F42A, Y45A, L72G, and Q126T substitutions collectively create a binding interface that has reduced affinity for the α-subunit-containing high-affinity receptors on Treg cells while maintaining affinity for the βγ-dimeric intermediate-affinity receptors on cytotoxic T lymphocytes, achieving selective activation without requiring additional targeting mechanisms
Solution Approach 2:
The patent applies inversion by reversing the natural binding hierarchy. Instead of wild-type IL-2 which has highest affinity for high-affinity receptors (leading to Treg activation), the mutants are designed to have inverted affinity preferences, with relatively higher functional activity at intermediate-affinity receptors. This inverted binding profile flips the activation pattern from Treg-dominant to effector T cell-dominant, achieving the desired selectivity through reversed affinity relationships
3Productivity
If conventional IL-2 immunotherapy is used, then T cell proliferation is stimulated, but activation-induced cell death leads to tumor tolerance
Solution Approach 1:
The mutant IL-2 molecules apply partial action by providing sufficient stimulation for effector T cell proliferation and activation while deliberately avoiding the excessive activation threshold that triggers Treg-mediated immunosuppression and activation-induced cell death. The modified affinity profile delivers a calibrated level of signaling that is adequate for anti-tumor immunity but sub-threshold for the harmful feedback mechanisms, achieving productive T cell expansion without inducing tumor tolerance
Data Source
AI summary
The present invention generally relates to immunoconjugates, particularly immunoconjugates comprising a mutant interleukin-2 polypeptide and an antibody that binds to PD-1. In addition, the invention relates to polynucleotide molecules encoding the immunoconjugates, and vectors and host cells comprising such polynucleotide molecules. The invention further relates to methods for producing the mutant immunoconjugates, pharmaceutical compositions comprising the same, and uses thereof.