CCHFV Replicon Particles for Single-Round Broad Immunity
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Solution Overview
Problem
Current vaccines and treatments for Crimean-Congo hemorrhagic fever virus (CCHFV) are inadequate, with high mortality rates and no FDA-approved options, and existing vaccine approaches require multiple administrations or face safety and manufacturing issues, failing to provide broad protection against genetically divergent strains.
Innovation Solution
Development of CCHF virus replicon particles (VRPs) that undergo one round of replication, lacking the M-segment to prevent spread, and produce conserved L-protein and nucleoprotein, inducing protective immunity through a single dose.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional vaccine approaches are used, then vaccine development is achieved, but multiple administrations are required and broad protection against divergent strains is not provided
Solution Approach 1:
The virus genome is segmented into three RNA segments (S, M, L), and the vaccine uses a modified minigenome containing only the S and L segments without the M segment. This segmentation allows the vaccine to produce viral proteins and replicate without producing infectious virus particles, thereby providing broad protection against divergent strains while maintaining safety.
Solution Approach 2:
The M segment encoding the glycoprotein precursor (GPC) is extracted/removed from the viral genome in the vaccine construct. This extraction prevents the production of infectious virus particles while preserving the ability to produce conserved viral proteins (L-protein and nucleoprotein) that elicit protective immunity against divergent CCHFV strains.
2Reliability
If replicon particles undergo full replication, then immune response is generated, but virus spread occurs
Solution Approach 1:
The M segment encoding the glycoprotein precursor (GPC) is extracted from the viral genome, which is essential for virus assembly and spread. The replicon particles can undergo one round of replication and generate immune response but cannot produce infectious virus particles that would spread the virus, thus eliminating the harmful effect of virus spread while maintaining the beneficial immune response.
3Reliability
If existing vaccines are used, then some protection is achieved, but safety issues and manufacturing challenges arise
Solution Approach 1:
The patent uses a synthetic DNA-based replicon system that copies essential viral genes (S and L segments) into a plasmid vector. This copying approach allows for standardized, scalable production in insect cells using well-established molecular biology techniques, avoiding the safety and manufacturing complexities of traditional live-attenuated or killed virus vaccines.
Solution Approach 2:
The patent modifies the viral genome by deleting the M segment and incorporating a synthetic minigenome, changing the replication parameters to allow one round of replication without virus spread. This parameter change enables the use of insect cell expression systems for manufacturing, improving ease of production while maintaining vaccine efficacy through the production of conserved viral proteins.
Data Source
AI summary
Crimean-Congo hemorrhagic fever (CCHF) virus replicon particles (VRP) are described. These VRP are capable of undergoing a single round of virus replication, but are unable to produce new particles or spread to neighboring cells due to the lack of the glycoprotein-encoding M genome segment. In some instances, the VRP contains one or more mutations in the viral ovarian tumor domain protease encoded by the L genome segment or heterologous antigens within its S genome segment. These VRP are shown to elicit a protective immune response against lethal CCHF virus challenge in an animal model.