Abstract
Virus-like particles (VLPs) resemble authentic virus while not containing any genomic information. Here, we present a fast and powerful method for the production of SARS-CoV-2 VLP in insect cells and the application of these VLPs to evaluate the inhibition capacity of monoclonal antibodies and sera of vaccinated donors. Our method avoids the baculovirus-based approaches commonly used in insect cells by employing direct plasmid transfection to co-express SARS-CoV-2 envelope, membrane, and spike protein that self-assemble into VLPs. After optimization of the expression plasmids and vector ratios, VLPs with an ~145 nm diameter and the typical “Corona” aura were obtained, as confirmed by nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM). Fusion of the membrane protein to GFP allowed direct quantification of binding inhibition to angiotensin II-converting enzyme 2 (ACE2) on cells by therapeutic antibody candidates or sera from vaccinated individuals. Neither VLP purification nor fluorescent labeling by secondary antibodies are required to perform these flow cytometric assays.
Keywords: SARS-CoV-2; antibodies; cellular assay; expression vector; insect cells; virus-like particles (VLPs).
【저자키워드】 antibodies, SARS-CoV-2, Virus-like particles (VLPs)., insect cells, expression vector, cellular assay, 【초록키워드】 ACE2, antibody, monoclonal antibody, virus, Spike protein, Particle, membrane protein, sera, therapeutic, membrane, donors, fusion, quantification, transmission electron microscopy, expression, VLP, binding, cellular, Analysis, Virus-like particle, enzyme, candidate, vaccinated individuals, fluorescent, purification, VLPs, labeling, SARS-CoV-2 envelope, genomic information, TEM, GFP, Cell, flow cytometric, secondary antibody, evaluate, approach, assays, required, insect cell, expression plasmid, NTA, plasmid transfection, 【제목키워드】 Production, Particle, Rapid, assessment, insect,