Immunization with a fusion protein vaccine candidate generated from truncated peptides of human enterovirus 71 protects mice from lethal enterovirus 71 infections

Abstract

Background: Prophylactic vaccines are critical in preventing hand, foot, and mouth disease (HFMD) primarily caused by human enterovirus 71 (EV71) infection. Children aged less than 5 years are especially susceptible to EV71 infections. In addition to the development of vaccines containing the inactivated virus, those containing virus-like particles (VLPs) with repeated antigens also constitute an effective preventive strategy for EV71 infections, with safety and productivity advantages. We previously developed a fusion protein composed with truncated peptides of the EV71 capsid protein, which assembled into spherical particles. This study aimed to assess the immunoprotective effects of this fusion protein as a vaccine candidate in a mouse model of EV71 infection. Methods: To evaluate the protective effect of fusion protein vaccine candidate, neonatal mice born by immunized female mice, as well as normal neonatal mice immunized twice were infected with EV71 virus. Whereafter, the survival rates, clinical scores and viral loads were measured. Results: The high dosage and booster immunization helped induce specific serum antibodies with high neutralization titers, which were transferred to neonatal mice, thereby facilitating effective resistance towards EV71 infection. An active immune response was also observed in neonatal mice which generated following immunization. Conclusions: The present results suggest that this fusion protein is a suitable vaccine candidate in treating EV71 infections.

A 10-Day-Old Murine Model of Coxsackievirus A6 Infection for the Evaluation of Vaccines and Antiviral Drugs

“…Moreover, the animal model built here can be used to evaluate active immunization from vaccines. In most of the existing studies, adult mice have been used for the immunization with vaccines, and the serum adoptive method was adopted to evaluate the immune effect of enterovirus vaccines ( 33 ). Thus, the real effect of active immunity cannot be reflected, especially the evaluation of cellular immune effect ( 34 , 35 ).…”