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6994543 
Journal Article 
Preparation of virus-like particle mimetic nanovesicles displaying the S protein of Middle East respiratory syndrome coronavirus using insect cells 
Kato, T; Takami, Y; Deo, VK; Park, EY; , 
2019 
Yes 
Journal of Biotechnology
ISSN: 0168-1656
EISSN: 1873-4863 
ELSEVIER 
AMSTERDAM 
177-184 
31614169 
WOS:000496193800022 
Middle East respiratory syndrome coronavirus (MERS-CoV) first emerged in 2012, and over 2000 infections and 800 deaths have been confirmed in 27 countries. However, to date, no commercial vaccine is available. In this study, structural proteins of MERS-CoV were expressed in silkworm larvae and Bm5 cells for the development of vaccine candidates against MERS-CoV and diagnostic methods. The spike (S) protein of MERS-CoV lacking its transmembrane and cytoplasmic domains (S Delta TM) was secreted into the hemolymph of silkworm larvae using a bombyxin signal peptide and purified using affinity chromatography. The purified S Delta TM forms small nanoparticles as well as the full-length S protein and has the ability to bind human dipeptidyl peptidase 4 (DPP4), which is a receptor of MERS-CoV. These results indicate that bioactive S Delta TM was expressed in silkworm larvae. To produce MERS-CoV-like particles (MERS-CoV-LPs), the coexpression of spike proteins was performed in Bm5 cells and envelope (E) and membrane (M) proteins secreted E and M proteins extracellularly, suggesting that MERS-CoV-LPs may be formed. However, this S protein was not displayed on virus-like particles (VLPs) even though E and M proteins were secreted into the culture supernatant. By surfactant treatment and mechanical extrusion using S protein- or three structural protein-expressing Bm5 cells, S protein-displaying nanovesicles with diameters of approximately 100-200 nm were prepared and confirmed by immuno-TEM. The mechanical extrusion method is favorable for obtaining uniform recombinant protein-displaying nanovesicles from cultured cells. The purified S Delta TM from silkworm larvae and S protein-displaying nanovesicles from Bm5 cells may lead to the development of nanoparticle-based vaccines against MERS-CoV and the diagnostic detection of MERS-CoV.