RNA Replicon for T Cell Receptor Expression
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Solution Overview
Problem
Current methods for expressing T cell receptors or artificial T cell receptors in immune effector cells, such as T cells, are inefficient and pose safety concerns due to the inclusion of non-functional alphavirus non-structural protein fragments, which can lead to unwanted side effects and regulatory issues.
Innovation Solution
Development of RNA replicons that uncouple sequence elements required for replication from protein-coding regions, allowing for the expression of T cell receptors or artificial T cell receptors without encoding non-structural proteins, and using alphavirus-derived vectors to efficiently amplify the open reading frames under the control of a subgenomic promoter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If alphavirus-based vectors are used to express T cell receptors in immune effector cells, then expression efficiency is improved, but non-functional alphavirus non-structural protein fragments are included which cause safety concerns and unwanted side effects
Solution Approach 1:
The patent extracts and removes the harmful non-structural protein fragments from the alphavirus vector while preserving the essential replication functions. This is achieved by deleting the open reading frames encoding non-structural proteins (nsP1-nsP4) from the alphavirus genome, leaving only the structural protein genes and replication recognition sequences. The resulting vector maintains replication capability through recognition of host cell factors but eliminates the production of harmful non-structural protein fragments, thus resolving the safety concerns while preserving expression efficiency.
Solution Approach 2:
The patent segments the alphavirus vector into functional modules: replication recognition sequences (5' and 3' UTRs), structural protein genes (capsid, envelope), and the inserted T cell receptor gene. By separating the replication function (provided by recognition sequences) from the protein-coding regions, the vector can replicate efficiently without encoding complete non-structural proteins, thereby achieving both high productivity and safety.
2Stability of the object's composition
If complete alphavirus vectors are used for T cell receptor expression, then replication capability is maintained, but regulatory issues and unwanted side effects arise from non-structural protein expression
Solution Approach 1:
The patent extracts only the essential replication recognition sequences from the alphavirus genome while removing the open reading frames that encode non-structural proteins. The 5' and 3' untranslated regions containing replication recognition elements are retained, allowing the vector to replicate by recognizing host cell machinery, but the genes for nsP1-nsP4 are completely deleted. This extraction approach maintains replication stability while eliminating regulatory issues associated with non-structural protein expression.
3Adaptability or versatility
If traditional TCR gene transfer methods are used, then antigen-specificity can be redirected, but expression efficiency and therapeutic efficacy are limited
Solution Approach 1:
The patent uses alphavirus replication recognition sequences as an intermediary mechanism to achieve high-efficiency T cell receptor expression. The viral 5' and 3' UTRs act as mediators that recruit host cell replication machinery, enabling robust amplification of the T cell receptor gene without requiring integration into the host genome. This intermediary approach maintains the adaptability to redirect antigen-specificity while dramatically improving expression efficiency and therapeutic efficacy compared to traditional gene transfer methods.
Data Source
AI summary
The present invention embraces a RNA replicon that can be replicated by a replicase of alphavirus origin and comprises an open reading frame encoding a chain of a T cell receptor or of an artificial T cell receptor. Such RNA replicons are useful for expressing a T cell receptor or an artificial T cell receptor in a cell, in particular an immune effector cell such as a T cell. Cells engineered to express such T cell receptor or artificial T cell receptor are useful in the treatment of diseases characterized by expression of antigens bound by the T cell receptor or artificial T cell receptor.