Engineered Lymphocyte Targeting Constructs Without Intracellular Signaling
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Solution Overview
Problem
Existing CAR T cell therapies face challenges with off-target cytotoxicity due to moderate expression of target antigens by healthy cells, necessitating improved methods to enhance safety and efficacy.
Innovation Solution
Engineering lymphocytes, such as γδ T cells, NK cells, and MAIT cells, with heterologous targeting constructs that lack a functional intracellular domain capable of activating the cell on which it is expressed. The engineered γδ T cells, NK-like T cells, and engineered mucosal-associated invariant T (MAIT) cells, with heterologous targeting constructs that lack a functional intracellular domain, enhancing specificity to diseased cells by avoiding aberrant TCR activation upon binding to low levels of target antigens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CAR T cells are engineered to recognize target antigens on cancer cells, then therapeutic efficacy is improved, but off-target cytotoxicity occurs due to moderate antigen expression on healthy cells
Solution Approach 1:
The invention divides the traditional CAR structure into separate functional modules: an extracellular antigen-binding domain and a transmembrane domain that terminates without intracellular signaling sequences. This segmentation allows the targeting function to be separated from the activation function, enabling selective binding to target cells without triggering unwanted activation against cells with moderate antigen expression.
Solution Approach 2:
The invention extracts and removes the intracellular signaling domain from the chimeric antigen receptor construct. By taking out the intracellular activation domain (such as CD3ζ signaling sequences), the receptor can bind to target antigens on healthy cells without propagating activation signals, thereby preventing off-target cytotoxicity while maintaining the ability to target cancer cells.
2Power
If lymphocytes are engineered with functional intracellular domains to activate upon antigen binding, then cytotoxic activity is enhanced, but specificity to diseased cells is reduced
Solution Approach 1:
The invention applies local quality by creating a receptor structure with different functional properties at different locations: the extracellular domain maintains high affinity for target antigens to ensure specific recognition, while the transmembrane domain is designed to terminate without intracellular signaling capability. This local differentiation allows the receptor to bind specifically to diseased cells without triggering activation against cells with lower antigen expression levels.
3Productivity
If chimeric antigen receptors are designed with full intracellular signaling domains, then signal propagation and T cell activation are improved, but safety concerns arise from aberrant activation
Solution Approach 1:
The invention converts the potential harm of full signaling capability into a benefit by deliberately designing a truncated receptor that binds with high specificity but cannot activate. The extracellular domain's ability to recognize and bind target antigens is preserved and even enhanced, while the removed intracellular signaling domain prevents harmful aberrant activation. This transforms what could be a dangerous full-function receptor into a safe targeting tool that can be controlled through alternative activation mechanisms.
Data Source
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AI summary
The present invention provides engineered lymphocytes (e.g., γδ T cells, NK cells, NK-like T cells, engineered innate lymphoid cells, or MAIT cells) comprising a heterologous targeting construct lacking an intracellular signaling domain capable of activating the lymphocyte on which the construct is expressed. Further provided are compositions of engineered lymphocytes (e.g., γδ T cells) and methods of using the engineered lymphocytes (e.g., γδ T cells, e.g., a part of an adoptive T cell therapy).