Multi-chain CARs with Segmented Signaling Domains
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Solution Overview
Problem
Current chimeric antigen receptor (CAR) architectures, which are built as single fusion molecules, require serial appending of signaling domains, disrupting their natural juxtamembrane positions and impairing function, while existing adoptive immunotherapy using autologous cells faces challenges such as high costs, logistical hurdles, and immune rejection issues with allogeneic cells.
Innovation Solution
Design of multi-chain CARs with separate polypeptide subunits placing signaling domains in their natural juxtamembrane positions, allowing for flexible architecture with additional extracellular ligand binding domains and co-stimulatory molecules, and genetic modification of immune cells to be non-alloreactive and resistant to immunosuppressive agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If CARs are designed as single fusion molecules with serial appending of signaling domains, then the structure is simplified and easier to manufacture, but the signaling domains are displaced from their natural juxtamembrane positions impairing their function
Solution Approach 1:
The CAR is divided into separate polypeptide chains: one containing the extracellular ligand-binding domain and others containing the signal-transducing domains in their natural juxtamembrane positions. This segmentation restores the natural positioning of signaling domains while maintaining manufacturability through modular assembly of separate components.
Solution Approach 2:
The patent introduces transmembrane polypeptides as intermediaries that bridge the extracellular ligand-binding domain and the intracellular signal-transducing domains. These intermediaries maintain the natural juxtamembrane positioning of signaling domains while enabling functional communication across the membrane.
2Reliability
If autologous CAR T cells are used for immunotherapy, then the cells are genetically matched to the patient avoiding rejection, but the treatment faces high costs and logistical hurdles
Solution Approach 1:
The patent creates allogeneic CAR T cell products that can be standardized and pre-manufactured, serving as copies that are genetically matched to patient groups rather than requiring custom autologous cell generation for each patient. This reduces the complexity and cost while maintaining therapeutic effectiveness.
Solution Approach 2:
The patent modifies the genetic parameters of CAR T cells through CRISPR/Cas9-mediated gene editing to achieve non-alloreactivity and immunosuppressive resistance, enabling standardized allogeneic products that can be stored and administered without requiring patient-specific customization.
3Device complexity
If allogeneic CAR T cells are used for immunotherapy, then the treatment can be standardized and pre-manufactured reducing costs and complexity, but the cells face immune rejection by the host
Solution Approach 1:
The patent applies preliminary genetic modification using CRISPR/Cas9 to knock out alloreactive genes and introduce immunosuppressive resistance markers before cell manufacturing. This preliminary anti-action prevents immune rejection upon administration, enabling standardized allogeneic products to be compatible with multiple patients.
Solution Approach 2:
The patent creates composite genetically modified cells combining multiple functions: CAR expression, non-alloreactivity through gene knockout, and immunosuppressive resistance. This composite approach integrates multiple protective and functional properties into a single cell product that can be standardized and stored.
4Reliability
If signaling domains are placed in natural juxtamembrane positions in multi-chain CARs, then the functionality is improved, but the structural complexity increases
Solution Approach 1:
The CAR is segmented into separate polypeptide chains with distinct functions: one chain contains the extracellular ligand-binding domain while other chains contain the signal-transducing domains in their natural juxtamembrane positions. This segmentation enables improved functionality while the modular nature keeps the overall structure manageable.
Solution Approach 2:
The patent employs universal transmembrane polypeptide frameworks (such as FcεRI chains) that can serve multiple functions: providing the structural basis for juxtamembrane positioning, enabling signal transduction, and facilitating assembly with different extracellular ligand-binding domains. This multi-functionality reduces the need for entirely new structural elements.
Data Source
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AI summary
The present invention relates to the generation of chimeric antigen receptors (CAR) referred to as multi-chain CARs. Such CARs, which aim to redirect immune cell specificity and reactivity toward a selected target exploiting the ligand-binding domain properties, comprise separate extracellular ligand binding and signaling domains in different transmembrane polypeptides. The signaling domains are designed to assemble in juxtamembrane position, which forms flexible architecture closer to natural receptors, that confers optimal signal transduction. The invention encompasses the polynucleotides, vectors encoding said multi- chain CAR and the isolated cells expressing them at their surface, in particularly for their use in immunotherapy. The invention opens the way to efficient adoptive immunotherapy strategies for treating cancer and viral infections.