PDCD-1 Homing Endonuclease Editing for Exhaustion-Resistant T Cells
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Solution Overview
Problem
Current immunotherapy approaches for cancer, such as monoclonal antibodies targeting PDCD-1, have limited success due to systemic toxicity and a complex tumor microenvironment that induces T cell exhaustion, limiting their effectiveness in combating cancer.
Innovation Solution
Development of homing endonuclease variants, like I-OnuI HE, with enhanced stability and activity to cleave the human PDCD-1 gene, allowing for targeted editing and reducing PDCD-1 expression in T cells, thereby enhancing their resistance to immunosuppression and exhaustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If monoclonal antibodies targeting PDCD-1 are used for immunotherapy, then T cell activation is enhanced, but systemic toxicity increases
Solution Approach 1:
The patent applies local quality by using genome editing to modify PDCD-1 expression specifically in T cells rather than systemically. By introducing point mutations or deletions in the PDCD-1 gene within T cell genomes, the therapy achieves localized effect on the target cells without widespread systemic activation, thereby reducing off-target toxicity while maintaining anti-tumor efficacy.
Solution Approach 2:
The patent segments the therapeutic approach by dividing it into distinct steps: first isolating T cells, then performing in vitro genome editing on the PDCD-1 gene, and finally reinfusing the modified cells. This segmentation allows precise control over where and how PDCD-1 is modified, avoiding uncontrolled systemic effects.
2Reliability
If T cells are exposed to tumor microenvironment, then they recognize tumor antigens, but T cell exhaustion increases
Solution Approach 1:
The patent applies preliminary anti-action by pre-modifying T cells ex vivo to reduce or eliminate PDCD-1 expression before they encounter the tumor microenvironment. By removing the PDCD-1 inhibitory receptor in advance, T cells are prepared to resist exhaustion signals from the tumor environment, maintaining their effector function and persistence longer than unmodified T cells.
3Reliability
If genome editing is performed on PDCD-1 gene, then T cell function is enhanced, but editing precision must be maintained
Solution Approach 1:
The patent applies parameter changes by using CRISPR-Cas9 system with specifically designed guide RNAs and donor templates to achieve precise edits at the PDCD-1 gene locus. By optimizing parameters such as guide RNA sequence design, Cas9 fidelity variants, and homology arm lengths in donor templates, the system achieves high precision editing with desired point mutations or deletions while minimizing off-target effects.
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 engineered T cells become more persistent and therapeutically efficacious, overcoming the limitations of existing immunotherapies by maintaining anti-tumor function and reducing T cell exhaustion.
Implementation Method 1
The I-OnuI HE variant binds and cleaves a target site in the human PDCD-1 gene
Data Source
AI summary
The present disclosure provides improved homing endonuclease variants and megaTALs reprogrammed to bind and cleave the PDCD-1 gene.