CLL-1-Targeted CAR Architectures for Persistent T-Cell Signaling
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Solution Overview
Problem
Existing CAR T cell therapies for cancer treatment face limitations such as poor CAR expression, rapid cell disappearance, antigen escape, and suboptimal clinical activity, necessitating improved CAR architectures and enhanced immune effector cell machinery for sensing and integrating chemical and biological information.
Innovation Solution
Development of VHH-based dimerizing agent regulated immunoreceptor complexes (DARICs) and chimeric antigen receptors (CARs) targeting CLL-1, comprising specific polypeptides and bridging factors like FKBP and FRB domains, which form functional complexes on the cell surface to enhance spatial and temporal control over immune cell signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If scFv-based chimeric antigen receptors (CARs) are used for cancer treatment, then CAR T cell therapy can be administered, but poor CAR expression and rapid cell disappearance occur
Solution Approach 1:
The CAR is divided into separate functional domains: a CLL-1 binding domain (VHH antibody fragment), a transmembrane domain, and intracellular signaling domains (CD137 and CD3ζ). This segmentation allows each component to be optimized independently for its specific function, improving overall CAR expression and cell persistence.
Solution Approach 2:
The CAR combines multiple signaling domains (CD137 co-stimulatory domain and CD3ζ primary signaling domain) within a single receptor structure. This composite architecture provides both activation and co-stimulation signals, enhancing T cell persistence and preventing rapid cell disappearance.
2Reliability
If existing CAR architectures are used, then CAR T cell therapy can be delivered, but antigen escape and suboptimal clinical activity occur
Solution Approach 1:
The VHH antibody domain is specifically designed to bind CLL-1 with high affinity and specificity. This localized optimization of the binding domain ensures precise targeting of CLL-1-expressing cancer cells, preventing antigen escape and improving clinical activity.
Solution Approach 2:
The intracellular signaling domains are engineered with specific amino acid sequences and structural configurations to optimize signal transduction efficiency. This parameter optimization enhances the receptor's ability to translate ligand binding into cellular responses, improving clinical activity.
3Productivity
If CAR T cell therapy is administered, then cancer treatment can be provided, but the cells rapidly disappear after infusion
Solution Approach 1:
The CAR includes pre-configured co-stimulatory (CD137) and primary signaling (CD3ζ) domains that are ready to activate T cells upon CLL-1 binding. This preliminary preparation of signaling machinery ensures rapid and sustained T cell activation, extending cell lifespan and maintaining therapeutic effect.
Solution Approach 2:
The dual-domain signaling architecture provides continuous activation signals through both CD137 co-stimulation and CD3ζ primary signaling. This continuous signaling prevents T cell exhaustion and apoptosis, maintaining cell lifespan and sustained therapeutic activity in vivo.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The DARICs and CARs provide improved targeting and activation of immune cells, overcoming tonic signaling and antigen-independent issues, leading to enhanced therapeutic efficacy against CLL-1-expressing cancers like AML.
Implementation Method 1
a bridging factor promotes the formation of a polypeptide complex on the non-natural cell surface with the bridging factor associated with and disposed between the multimerization domains of the first and second polypeptides
Data Source
AI summary
The present disclosure provides improved CLL-1 targeting polypeptides and compositions for adoptive T cell therapies for treating, preventing, or ameliorating at least one symptom of a cancer, infectious disease, autoimmune disease, inflammatory disease, and immunodeficiency, or condition associated therewith.