Efficient production of recombinant SARS-CoV-2 spike protein using the baculovirus-silkworm system

Abstract

In the case of a new viral disease outbreak, an immediate development of virus detection kits and vaccines is required. For COVID-19, we established a rapid production procedure for SARS-CoV-2 spike protein (S protein) by using the baculovirus-silkworm expression system. The baculovirus vector-derived S proteins were successfully secreted to silkworm serum, whereas those formed insoluble structure in the larval fat body and the pupal cells. The ectodomain of S protein with the native sequence was cleaved by the host furin-protease, resulting in less recombinant protein production. The S protein modified in furin protease-target site was efficiently secreted to silkworm serum and was purified as oligomers, which showed immunoreactivity for anti-SARS-CoV-2 S2 antibody. By using the direct transfection of recombinant bacmid to silkworms, we achieved the efficient production of SARS-CoV-2 S protein as fetal bovine serum (FBS)-free system. The resultant purified S protein would be useful tools for the development of immunodetection kits, antigen for immunization for immunoglobulin production, and vaccines.

Emerging Silk Material Trends: Repurposing, Phase Separation and Solution-Based Designs

“…Silkworms have evolved to produce large amounts of protein and are thus ideally placed to be genetically re-programmed, allowing B. mori silkworms to also serve as biofactories of tailor-made high-value proteins [ 34 , 73 ]. For example, the use of the B. mori genetic toolbox made possible the expression the SARS-CoV-2 spike protein in silkworms [ 23 ], and the use of silkworms to generate virus-like particles is expected to contribute to the SARS-CoV-2 vaccine pipeline.…”

“… Summary of emerging silk material trends. Repurposing [ 23 , 25 , 27 , 28 ], solution-based designs [ 24 ], phase separation [ 30 , 31 ] and flow [ 22 , 26 , 29 ] impacting manufacturing and creating living materials. …”

“…In this review, I have selected key primary research papers published in 2020 (references [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ]) that I believe will change the silk material space ( Figure 1 ). Typically, technological innovations have catalyzed the fields that ultimately delivered the most impact.…”

Clomipramine suppresses ACE2-mediated SARS-CoV-2 entry

“…The copyright holder for this preprint this version posted March 14, 2021. ; https://doi.org/10.1101/2021.03.13.435221 doi: bioRxiv preprint Recombinant SARS-CoV-2 spike protein (S protein) were purified using the baculovirussilkworm system 32…”

“…Recombinant SARS-CoV-2 spike protein (S protein) were purified using the baculovirussilkworm system 32 . Purified S protein were chemically labeled with a fluorescent probe using HiLyte Fluor 555 Labeling Kit-NH2 (Dojindo).…”