Inactivated Enterovirus 71 Vaccine Produced by 200-L Scale Serum-Free Microcarrier Bioreactor System Provides Cross-Protective Efficacy in Human SCARB2 Transgenic Mouse

PLoS One. 2015 Aug 19;10(8):e0136420. doi: 10.1371/journal.pone.0136420. eCollection 2015.

Abstract

Epidemics and outbreaks caused by infections of several subgenotypes of EV71 and other serotypes of coxsackie A viruses have raised serious public health concerns in the Asia-Pacific region. These concerns highlight the urgent need to develop a scalable manufacturing platform for producing an effective and sufficient quantity of vaccines against deadly enteroviruses. In this report, we present a platform for the large-scale production of a vaccine based on the inactivated EV71(E59-B4) virus. The viruses were produced in Vero cells in a 200 L bioreactor with serum-free medium, and the viral titer reached 10(7) TCID50/mL 10 days after infection when using an MOI of 10(-4). The EV71 virus particles were harvested and purified by sucrose density gradient centrifugation. Fractions containing viral particles were pooled based on ELISA and SDS-PAGE. TEM was used to characterize the morphologies of the viral particles. To evaluate the cross-protective efficacy of the EV71 vaccine, the pooled antigens were combined with squalene-based adjuvant (AddaVAX) or aluminum phosphate (AlPO4) and tested in human SCARB2 transgenic (Tg) mice. The Tg mice immunized with either the AddaVAX- or AlPO4-adjuvanted EV71 vaccine were fully protected from challenges by the subgenotype C2 and C4 viruses, and surviving animals did not show any degree of neurological paralysis symptoms or muscle damage. Vaccine treatments significantly reduced virus antigen presented in the central nervous system of Tg mice and alleviated the virus-associated inflammatory response. These results strongly suggest that this preparation results in an efficacious vaccine and that the microcarrier/bioreactor platform offers a superior alternative to the previously described roller-bottle system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bioreactors
  • Chemokines / genetics
  • Chlorocebus aethiops
  • Coxsackievirus Infections / genetics
  • Coxsackievirus Infections / immunology
  • Coxsackievirus Infections / prevention & control
  • Cross Reactions
  • Cytokines / genetics
  • Enterovirus A, Human / immunology*
  • Gene Expression
  • Humans
  • Lysosomal Membrane Proteins / genetics*
  • Lysosomal Membrane Proteins / immunology*
  • Mice
  • Mice, Inbred BALB C
  • Mice, Transgenic
  • Rabbits
  • Receptors, Scavenger / genetics*
  • Receptors, Scavenger / immunology*
  • Vaccines, Inactivated / biosynthesis
  • Vaccines, Inactivated / immunology
  • Vero Cells
  • Viral Vaccines / biosynthesis
  • Viral Vaccines / immunology*
  • Virus Cultivation

Substances

  • Chemokines
  • Cytokines
  • Lysosomal Membrane Proteins
  • Receptors, Scavenger
  • SCARB2 protein, human
  • Vaccines, Inactivated
  • Viral Vaccines

Grants and funding

This study was supported by funds from Adimmune Corporation, Enimmune Corporation and the Ministry of Economic Affairs, Taiwan (grant no. 101-EC-17-A-20-I1-0054). Enimmune is a subsidiary of Adimmune Corp. Coauthors CYW, CHK, WHL, HFT, CHP, YTC, CHC, CCC, CCL and JRC are all employees of Adimmune Corporation. CCL is also serving as acting general manager of Enimmune Corporation. The parties provided the financial support in the form of salaries for authors, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.