CIRB Chimeric Protein for NK Cell Self-Activation
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Solution Overview
Problem
Current immunotherapy strategies using IL2 to enhance NK cell activity face limitations due to severe side effects, short IL2 half-life, and suppression by T-regs and MDSCs, leading to limited anti-tumor efficacy and systemic toxicity.
Innovation Solution
Development of chimeric proteins like CIRB (IL2-IL2Rβ) and CIRB21 (IL2-IL2Rβ-IL21R) that allow NK cells to self-activate and proliferate indefinitely without exogenous IL2, combined with pore-forming proteins like L-Holin to induce immune cell destruction, reducing systemic toxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If systemic IL2 is administered to enhance NK cell activity, then anti-tumor efficacy is improved, but severe systemic side effects occur
Solution Approach 1:
The patent makes NK cells locally produce IL2 through the CIRB chimeric protein, which is expressed specifically in NK cells and activates them in situ. This localized production eliminates the need for systemic IL2 administration, thereby maintaining anti-tumor efficacy while avoiding systemic side effects such as capillary leak syndrome and immunosuppression
Solution Approach 2:
The CIRB chimeric protein enables NK cells to self-activate and self-proliferate by providing constitutive IL2 signaling within the NK cell itself. The chimeric protein consists of IL2 fused to IL2Rβ, creating an autonomous activation system that does not require external IL2 administration, thus eliminating systemic toxicity while maintaining therapeutic efficacy
2Reliability
If exogenous IL2 is used to activate NK cells, then NK cell cytotoxicity is enhanced, but IL2 is rapidly depleted by T-regs and other lymphoid cells
Solution Approach 1:
The CIRB chimeric protein is expressed within NK cells and provides constitutive IL2 signaling that does not depend on external IL2 sources. This self-contained activation mechanism ensures that NK cells can maintain cytotoxicity and proliferation without competing with T-regs for exogenous IL2, as the IL2 is produced and utilized locally within the NK cell compartment
Solution Approach 2:
Instead of administering IL2 systemically and hoping NK cells capture it before other cells do, the patent inverts the approach by making NK cells themselves the source of IL2 signaling through the CIRB chimeric protein. This reverses the traditional paradigm where NK cells are passive recipients of IL2, transforming them into active producers, thereby ensuring preferential activation without competition
3Reliability
If high dose IL2 is administered to sustain NK cytotoxicity, then anti-tumor activity is maintained, but severe sepsis-like side effects occur
Solution Approach 1:
The CIRB chimeric protein enables localized IL2 production specifically within NK cells, eliminating the need for high-dose systemic IL2 administration. This localized approach maintains NK cytotoxicity through autonomous cell-intrinsic signaling while avoiding the systemic inflammatory response and capillary leak syndrome characteristic of high-dose IL2 therapy
Solution Approach 2:
The chimeric protein creates a self-sustaining activation system where NK cells produce and respond to IL2 signals internally through the constitutive CIRB expression. This self-service mechanism maintains cytotoxicity without requiring external IL2 supplementation, thereby eliminating sepsis-like side effects while sustaining anti-tumor activity
Data Source
AI summary
Described herein are immune cells (e.g., natural killer (NK), T cells) expressing a chimeric protein comprising IL2 and IL2Rβ (e.g., CIRB), a chimeric protein comprising IL2, IL2Rβ and IL21R (e.g., CIRB21), a chimera protein comprising IL2, IL2Rβ, and CD28 (e.g., CIRB28), or a combination thereof, and comprising a nucleic acid encoding a pore-forming protein, and methods of using such immune cells for treating a subject (e.g., a subject having cancer, graft-versus-host disease (GVHD), or an autoimmune disease. Expression of the pore-forming protein can be induced to promote destruction of immune cells expressing CIRB, CIRB21, CIRB28, or a combination thereof.