Chimeric Receptor Engineering for Enhanced T-Cell ADCC
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Solution Overview
Problem
Current cancer therapies face challenges in enhancing the efficacy of antibody-based treatments, particularly in mediating effective antibody-dependent cell cytotoxicity (ADCC) in T lymphocytes, which lack activating FcγR, limiting their ability to target and kill cancer cells efficiently.
Innovation Solution
Development of a chimeric receptor comprising an extracellular ligand-binding domain of the high-affinity V158 FCGR3A variant, combined with the hinge and transmembrane domains of CD8α and signaling domains of CD3ζ and 4-1BB, which is expressed in T lymphocytes to confer ADCC capability, enhancing their affinity for therapeutic antibodies like Rituximab and Trastuzumab, thereby augmenting their anti-tumor potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If T lymphocytes are used for cancer therapy, then they can target tumor cells, but they lack activating FcγR and cannot mediate effective antibody-dependent cell cytotoxicity (ADCC)
Solution Approach 1:
The patent merges the extracellular ligand-binding domain of FcγR (specifically FCGR3A) with the T lymphocyte receptor complex by introducing chimeric receptors (CD16V-BB-ζ and CD16V-γ) that combine FcγR binding capability with T-cell signaling domains. This allows T lymphocytes to acquire both antibody binding ability and activation capability, resolving the contradiction between maintaining T-cell targeting function and gaining ADCC capability.
Solution Approach 2:
The chimeric receptors are constructed as composite molecular structures combining domains from different sources: the extracellular domain of FcγR for antibody binding, the transmembrane domain for cell membrane integration, and intracellular signaling domains (such as ζ and 4-1BB) for T-cell activation. This composite structure enables T lymphocytes to function with both B-cell-like antibody recognition and T-cell-like cytotoxicity.
2Strength
If conventional antibody therapy is used, then it can bind to cancer cells, but it lacks sufficient cytotoxicity without effective ADCC mediation
Solution Approach 1:
The chimeric receptor acts as an intermediary that bridges the antibody-cancer cell interaction and T-cell activation. By expressing FcγR binding domains on T lymphocytes, the system creates a tripartite interaction where the antibody bound to cancer cells can directly activate the T lymphocyte through the chimeric receptor, mediating potent cytotoxicity without requiring natural killer cells or other FcγR-expressing cells.
3Reliability
If FcγR polymorphisms are considered for treatment selection, then patients with V/V genotype show superior responses, but this limits treatment accessibility to specific patient populations
Solution Approach 1:
The chimeric receptor design allows T lymphocytes to self-acquire high-affinity FcγR binding capability through genetic modification, eliminating the need for patients to possess specific FcγR polymorphisms. By engineering the T cells themselves to express functional FcγR domains, the therapy becomes universally applicable to all patients regardless of their natural FcγR genotype, while still achieving the high ADCC efficacy previously limited to V/V genotype patients.
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3A~3D
AI summary
The present disclosure is directed to chimeric receptors that binds the Fc portion of human immunoglobulin and delivers activation signals. The chimeric receptor of the present disclosure may comprise an extracellular ligand-binding domain of F158 FCGR3A or the high-affinity V158 FCGR3A variant, the hinge and transmembrane domains of CD8α, and the signaling domains of CD3ζ and 4-1BB. The chimeric receptor of the present disclosure has a high affinity for Rituximab, Trastuzumab, hu14.18K322A, and other therapeutic antibodies, making it useful for augmenting the efficacy of antibody therapy against various cancers.