PLOS ONE, 2019. 14(3), e0210477-, DOI: https://doi.org/10.1371/journal.pone.0210477

Efficient expression of enterovirus 71 based on virus-like particles vaccine

Hye-Jin Kim, Ho Sun Son;Sang Won Lee;Youngsil Yoon;Ji-Yeon Hyeon;Gyung Tae Chung;June-Woo Lee;Jung Sik Yoo

Abstract

Enterovirus (EV) 71 is the main pathogen associated with hand-foot-mouth disease (HFMD)and can lead to the disease with severe mortality in children. Since 2009, in the Republic ofKorea, an outbreak of EV71 C4a infection with neurologic involvement emerged, where inHFMD involvement was identified and central nervous system complications were reported.In this study, EV71 C4a virus-like particles (VLPs) produced by recombinant technologywere generated in a baculovirus expression system. To improve the production yield, EV71VLP was constructed using the dual promoter system baculovirus P1 and 3CD (baculo-P1-3CD), which harbored both the structural protein-encoding P1 region under the control ofthe polyhedron promoter and the 3CD protease gene under the regulation of the CMV-IE,lef3, gp41, or chitinase promoters to augment the level of gene tranion. Efficient VLPexpression was demonstrated through optimization of incubation time and insect cell type.In addition, to evaluate the potential of VLP as a vaccine candidate, we tested the neutralizingantibodies and total anti-EV71 IgG from the purified EV71 C4a VLP serum. The recombinantEV71 VLP exhibited the morphology of self-assembled VLP, as determined by electronmicroscopy. Use of baculo-P1-3CD-gp41 led to a high yield (11.3mg/L < 40kDa) of VLPs inHigh-FiveTM cells at 3 days post-infection. Furthermore, the potential of VLP as a vaccinewas evaluated through the neutralizing ability elicited by the purified EV71 VLP after immunizationof BALB/c mice, which was shown to induce potent and long-lasting humoral immuneresponses as evidenced by the cross-neutralization titer. Our results could be used to expeditethe developmental process for vaccines under clinical trials and to ensure manufacturingconsistency for licensing requirements.

• DOI: https://doi.org/10.1371/journal.pone.0210477
• ISBN or ISSN: 1932-6203

• 본 연구는 질병관리본부 연구개발과제연구비를 지원받아 수행되었습니다.
• This research was supported by a fund by Research of Korea Centers for Disease Control and Prevention.