CHO-Derived SARS-CoV-2 eVLPs With Stabilized Full-Length Spike
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Solution Overview
Problem
There is a desire for virus-like particles (VLPs) that display the SARS-CoV-2 S antigen, which can be readily produced and elicit a robust immune response, addressing the limitations of existing vaccine technologies.
Innovation Solution
Enveloped virus-like particles (eVLPs) are produced by expressing a substantially full-length recombinant SARS-CoV-2 spike protein in animal host cells, such as CHO cells, with mutations to reduce ER retention and stabilize the prefusion conformation, and optionally incorporating additional recombinant proteins, to form eVLPs that are isolated and purified.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SARS-CoV-2 spike protein is expressed in host cells to form VLPs, then immune response is elicited, but production complexity and purification difficulty increase
Solution Approach 1:
The patent extracts and utilizes the endogenous retroviral particle formation mechanism of CHO cells to produce SARS-CoV-2 VLPs. By introducing only the SARS-CoV-2 spike protein gene into CHO cells, the system leverages the cell's natural retroviral particle assembly pathway to generate VLPs, which are then purified from cell culture supernatant. This approach simplifies production by relying on the host cell's inherent capabilities rather than requiring complex external assembly systems.
2Reliability
If full-length spike protein is used to maintain native structure, then immune response is improved, but protein stability and solubility decrease
Solution Approach 1:
The patent modifies the spike protein sequence by introducing specific mutations: a C-terminal truncation (deleting the endoplasmic reticulum retention signal) to improve solubility and secretion, and the 2P mutation (K986P, V987P) to stabilize the prefusion conformation. These parameter changes maintain the immunogenicity of the full-length spike protein while resolving stability and solubility issues that would otherwise hinder production.
3Productivity
If VLPs are produced in animal host cells, then production scalability is improved, but risk of endogenous retroviral contamination increases
Solution Approach 1:
The patent converts the potential harm of endogenous retroviral contamination into a benefit by deliberately exploiting the CHO cell's endogenous retroviral particle formation mechanism for productive VLP generation. The same cellular pathway that could cause contamination is harnessed to assemble SARS-CoV-2 VLPs, which are then purified from the supernatant. This approach maintains scalability while transforming a risk into a manufacturing advantage.
Data Source
AI summary
Provided is an enveloped virus-like particle (eVLP) comprising a substantially full-length recombinant SARS-CoV-2 spike (S) protein. The eVLP may further comprise an additional recombinant SARS-CoV-2 S protein having a different sequence, another recombinant viral antigen, or a recombinant non-viral protein. The eVLP is derived from an animal cell, such as a CHO cell, expressing the recombinant SARS-CoV-2 spike protein. Also provided are methods of producing such eVLPs, compositions including such eVLPs, and methods and uses for the induction of an immune response against a SARS-CoV-2 spike protein and/or prevention of COVID-19 or SARS-CoV-2 infection, employing such eVLPs.