title: Comparative evaluation of two hemagglutinating encephalomyelitis coronavirus vaccine candidates in mice.
abstract: Porcine hemagglutinating encephalomyelitis (PHE) is caused by the coronavirus hemagglutinating encephalomyelitis virus (PHE-CoV), and the recent, rapid spread of PHE-CoV in piglets from many countries emphasizes the urgent need for a PHE-CoV vaccine. Here we use a murine model for evaluation of the induction of humoral and cellular immune responses by inactivated and PHE-CoV DNA vaccines in order to define the immune correlates for protection against PHE-CoV. The inactivated vaccine was composed of purified PHE-CoV and aluminum hydroxide gel (alum), which was chosen as an adjuvant because of its long history of safety for human use. The PHE-CoV DNA vaccine was constructed by subcloning the S1 gene of PHE-CoV into the pVAX1 vector to create the recombinant plasmid pV-S1. Our results showed that the inactivated PHE-CoV vaccine (IPV) elicited a high level of humoral immunity, resulting in good protection efficacy against PHE-CoV challenge. The IPV induced the IgG1 subclass of serum antibodies and expression of the cytokine interleukin-4 (IL-4), suggesting that the IPV generated a predominantly Th2-type immune response. The DNA vaccine was found to mediate primarily a cellular immune response with high levels of IgG2a and the cytokines IL-2 and gamma interferon (IFN-γ). However, mice that were vaccinated twice with the DNA vaccine and boosted with the IPV could mount a sufficient neutralizing antibody response against live PHE-CoV, with little variation in IgG1 and IgG2a levels, and showed high levels of IL-2 and IL-4. This response may activate both B and T cells to mount a specific humoral and cellular immune response that could, in turn, elicit a phagocyte-mediated defense against PHE-CoV infections to achieve viral clearance.
authors.affiliation: College of Animal Science and Veterinary Medicine, Jilin University, Changchun, China.
authors.forename: Keyan
authors.initials: K
authors.lastname: Chen
authors.forename: Kui
authors.initials: K
authors.lastname: Zhao
authors.forename: Wenqi
authors.initials: W
authors.lastname: He
authors.forename: Wei
authors.initials: W
authors.lastname: Gao
authors.forename: Chuanbo
authors.initials: C
authors.lastname: Zhao
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Pan
authors.forename: Deguang
authors.initials: D
authors.lastname: Song
authors.forename: Chengli
authors.initials: C
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000534:Alum Compounds / Q000008:administration & dosage; D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D017934:Coronavirus / Q000276:immunology*; D018352:Coronavirus Infections / Q000276:immunology / Q000517:prevention & control*; D004195:Disease Models, Animal; D005260:Female; D007074:Immunoglobulin G / Q000097:blood; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology*; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D000534:Alum Compounds; D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D007074:Immunoglobulin G; D007376:Interleukin-2; D019444:Vaccines, DNA; D015164:Vaccines, Inactivated; D014614:Vaccines, Synthetic; D014765:Viral Vaccines; D015847:Interleukin-4; C041524:aluminum sulfate; D007371:Interferon-gamma