Self-Replicating RNA Vectors for Immune Cell Engineering
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Solution Overview
Problem
Current RNA-based vectors for immunotherapy are prone to degradation and require efficient delivery methods, and their use in genetically modifying immune competent cells beyond antigen-presenting cells remains unexplored for inducing specific immune responses.
Innovation Solution
Development of self-replicating RNA molecules encoding chimeric antigen receptors or antibodies, specifically designed for immune competent cells like NK cells, which include an extracellular single-chain variant fragment, an intracellular activation domain, and a transmembrane linker, to target tumor neoepitopes or self-lipids, enhancing immune therapy effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RNA-based vectors are used to deliver genetic information into cells, then delivery efficiency can be improved through optimized delivery methods, but the RNA is prone to degradation and requires complex delivery systems
Solution Approach 1:
The RNA vector is engineered to be self-replicating, containing its own replication machinery (RNA-dependent RNA polymerase) that allows it to autonomously replicate within the host cell cytoplasm without requiring repeated delivery. This self-service capability resolves the contradiction by providing sustained RNA presence and protein expression while eliminating the need for complex repeated delivery systems
Solution Approach 2:
The RNA vector is constructed as a composite system combining the replicable backbone (from alphavirus or other RNA viruses) with heterologous gene sequences of interest. This composite structure allows the RNA to function both as a stable replicating element and as a vehicle for delivering specific genetic information, resolving the stability-delivery efficiency contradiction
2Productivity
If self-replicating RNA is used to achieve rapid and high quantity cytoplasmic RNA replication, then expression levels of heterologous proteins are improved, but the system becomes more complex requiring viral replication enzymes
Solution Approach 1:
The RNA-dependent RNA polymerase encoded by the replicable backbone serves multiple functions: it replicates the viral backbone RNA and simultaneously replicates the heterologous gene sequences. This multi-functionality allows high-level protein expression from heterologous genes without requiring separate replication systems for each gene, resolving the productivity-complexity contradiction
Solution Approach 2:
The replication machinery and the heterologous gene expression system are merged into a single integrated RNA molecule. The replicable backbone and heterologous sequences are combined in one continuous RNA transcript that is replicated as a unit, simplifying the overall system while maintaining high expression levels through autonomous replication
3Adaptability or versatility
If conventional RNA vectors are used for genetically modifying immune competent cells, then delivery to antigen-presenting cells is achieved, but application to other immune competent cells for inducing specific immune responses remains limited
Solution Approach 1:
The self-replicating RNA vector system is designed with universal applicability to all immune competent cells (T cells, B cells, NK cells, dendritic cells, macrophages) rather than being restricted to antigen-presenting cells. The system maintains reliability in inducing specific immune responses across diverse cell types by leveraging the inherent replicative capacity and protein expression capability of the RNA vector in each cell type
Data Source
AI summary
Compositions, methods and uses of self-replicating RNA molecules that include a recombinant nucleic acid encoding a protein of interest such as a chimeric antigenic receptor or an antibody are presented. The self-replicating RNA molecule are introduced into an immune competent cell such that the chimeric antigenic receptor or the antibody are efficiently expressed in the immune competent cell while increasing the stability of the recombinant nucleic acid in the cell and reducing the potential integration of the recombinant nucleic acid into the genome of the immune competent cell.