Immune responses induced by DNA vaccines bearing Spike gene of PEDV combined with porcine IL-18

Virus Res. 2012 Aug;167(2):259-66. doi: 10.1016/j.virusres.2012.05.007. Epub 2012 May 19.

Abstract

Porcine epidemic diarrhea virus (PEDV) is the causative agent of porcine epidemic diarrhea, a highly contagious enteric disease of swine. The Spike (S) protein is one of the main structural proteins of PEDV capable of inducing neutralizing antibodies in vivo. Herein, we generated three distinct DNA constructs in the eukaryotic expression plasmid pVAX1; one encoding the S protein [pVAX1-(PEDV-S)], the second encoding the N-terminal fragment (S1) [pVAX1-(PEDV-S1)] containing potent antigenic sites, and the third expressing the porcine interleukin-18 (pIL-18) [pVAX1-(IL-18)]. Immunofluorescence assays in BHK-21 cells demonstrated successful protein expression from all 3 constructs. Kunming mice were injected separately with each of these constructs or with a pVAX1-(PEDV-S1)/pVAX1-(IL-18) combination, an attenuated PEDV vaccine, or vector only control. Animals were examined for T lymphocyte proliferation, anti-PEDV antibodies, IFN-γ and IL-4 protein levels, and cytotoxic T cell function in mouse peripheral blood and spleen. In all cases, results showed that pVAX1-(PEDV-S) and the combination of pVAX1-(PEDV-S1) with pVAX1-(IL-18) induced the strongest responses; however, pIL-18 had no adjuvant effects when given in combination with pVAX1-(PEDV-S1).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic / administration & dosage*
  • Adjuvants, Immunologic / genetics
  • Animals
  • Antibodies, Viral / blood
  • Blood / immunology
  • Cell Proliferation
  • Interferon-gamma / metabolism
  • Interleukin-18 / administration & dosage*
  • Interleukin-18 / genetics
  • Interleukin-4 / metabolism
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / immunology*
  • Mice
  • Plasmids
  • Porcine epidemic diarrhea virus / genetics
  • Porcine epidemic diarrhea virus / immunology*
  • Spike Glycoprotein, Coronavirus
  • Spleen / immunology
  • T-Lymphocytes / immunology
  • T-Lymphocytes, Cytotoxic / immunology
  • Vaccines, DNA / administration & dosage
  • Vaccines, DNA / genetics
  • Vaccines, DNA / immunology*
  • Viral Envelope Proteins / genetics
  • Viral Envelope Proteins / immunology*

Substances

  • Adjuvants, Immunologic
  • Antibodies, Viral
  • Interleukin-18
  • Membrane Glycoproteins
  • Spike Glycoprotein, Coronavirus
  • Vaccines, DNA
  • Viral Envelope Proteins
  • spike glycoprotein, SARS-CoV
  • spike protein, mouse hepatitis virus
  • Interleukin-4
  • Interferon-gamma