Modified WEEV Replicons for Immune-Evasive Protein Expression
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Solution Overview
Problem
Host cells develop intricate immune responses that compromise the efficacy of self-replicating RNA (srRNA) expression platforms, particularly for expressing beneficial proteins or therapeutic agents, as they detect and counter viral infection.
Innovation Solution
Development of nucleic acid constructs encoding a modified Western Equine Encephalitis virus (WEEV) genome or replicon, devoid of structural protein sequences, incorporating expression cassettes and heterologous nonstructural proteins, to enhance expression of heterologous genes in recombinant cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If self-replicating RNA (srRNA) is used to express beneficial proteins or therapeutic agents, then high-level expression is achieved, but host immune responses are activated that compromise efficacy
Solution Approach 1:
The patent extracts and removes the viral structural protein coding sequences from the srRNA construct, retaining only the nonstructural proteins necessary for replication. This extraction eliminates the trigger for host immune recognition while preserving the replication machinery needed for high-level therapeutic protein expression.
Solution Approach 2:
The patent uses a modified alphavirus replicon as an intermediary system that bridges the need for high-level protein expression and avoidance of immune detection. The replicon provides viral replication functions through nonstructural proteins while the deletion of structural proteins prevents immune activation, acting as a mediator between these conflicting requirements.
2Productivity
If complete viral genome is used for expression, then robust replication occurs, but immune detection and antiviral response increase
Solution Approach 1:
The patent extracts only the essential nonstructural protein coding sequences (nsP1-nsP4) required for viral RNA replication while removing the structural protein sequences (capsid, envelope proteins). This selective extraction maintains replication efficiency while eliminating immune detection triggers.
Solution Approach 2:
The patent segments the viral genome into functional components, separating the replication-essential nonstructural proteins from the immune-triggering structural proteins. This segmentation allows independent optimization of replication function while minimizing immunogenicity.
3Ease of manufacture
If structural protein sequences are included in srRNA, then viral particle formation occurs, but host cells activate innate immune defenses
Solution Approach 1:
The patent removes the structural protein coding sequences from the srRNA construct, eliminating the capability for complete viral particle formation while retaining the replication function. This extraction prevents immune activation by host pattern recognition receptors that detect viral structural components.
Solution Approach 2:
The patent converts the potential harm of viral particle formation (which triggers immune responses) into a benefit by using only the replication machinery without structural components. The absence of structural proteins, which would normally enable virion assembly, becomes advantageous by preventing immune detection while maintaining therapeutic protein expression.
Data Source
AI summary
The present disclosure relates to the field of molecular virology, including nucleic acid molecules comprising modified viral genomes or self-replicating RNAs, pharmaceutical compositions containing the same, and the use of such nucleic acid molecules and compositions for production of desired products in cell cultures or in a living body. Also provided are methods for eliciting a pharmacodynamic effect in a subject in need thereof, as well as methods for preventing and/or treating various health conditions.