Genotype I of Japanese Encephalitis Virus Virus-like Particles Elicit Sterilizing Immunity against Genotype I and III Viral Challenge in Swine

Sci Rep. 2018 May 10;8(1):7481. doi: 10.1038/s41598-018-25596-1.

Abstract

Swine are a critical amplifying host involved in human Japanese encephalitis (JE) outbreaks. Cross-genotypic immunogenicity and sterile protection are important for the current genotype III (GIII) virus-derived vaccines in swine, especially now that emerging genotype I (GI) JE virus (JEV) has replaced GIII virus as the dominant strain. Herein, we aimed to develop a system to generate GI JEV virus-like particles (VLPs) and evaluate the immunogenicity and protection of the GI vaccine candidate in mice and specific pathogen-free swine. A CHO-heparan sulfate-deficient (CHO-HS(-)) cell clone, named 51-10 clone, stably expressing GI-JEV VLP was selected and continually secreted GI VLPs without signs of cell fusion. 51-10 VLPs formed a homogeneously empty-particle morphology and exhibited similar antigenic activity as GI virus. GI VLP-immunized mice showed balanced cross-neutralizing antibody titers against GI to GIV viruses (50% focus-reduction micro-neutralization assay titers 71 to 240) as well as potent protection against GI or GIII virus infection. GI VLP-immunized swine challenged with GI or GIII viruses showed no fever, viremia, or viral RNA in tonsils, lymph nodes, and brains as compared with phosphate buffered saline-immunized swine. We thus conclude GI VLPs can provide sterile protection against GI and GIII viruses in swine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Neutralizing / genetics
  • Antibodies, Neutralizing / therapeutic use*
  • CHO Cells
  • COS Cells
  • Chlorocebus aethiops
  • Cricetinae
  • Cricetulus
  • Cross Protection* / genetics
  • Cross Protection* / immunology
  • Disease Models, Animal
  • Encephalitis Virus, Japanese / classification
  • Encephalitis Virus, Japanese / genetics*
  • Encephalitis Virus, Japanese / immunology*
  • Encephalitis, Japanese / genetics
  • Encephalitis, Japanese / immunology
  • Encephalitis, Japanese / therapy*
  • Female
  • Genotype
  • Japanese Encephalitis Vaccines / genetics
  • Japanese Encephalitis Vaccines / immunology
  • Japanese Encephalitis Vaccines / therapeutic use*
  • Mice
  • Mice, Inbred BALB C
  • RNA, Viral / genetics
  • Swine
  • Vaccination / methods*
  • Vaccination / veterinary
  • Vero Cells
  • Virion / genetics
  • Virion / immunology

Substances

  • Antibodies, Neutralizing
  • Japanese Encephalitis Vaccines
  • RNA, Viral