1. Comparative Evaluation of Two Hemagglutinating Encephalomyelitis Coronavirus Vaccine Candidates in Mice
- Author
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Chuanbo Zhao, Deguang Song, Chengli Wang, Wei Pan, Keyan Chen, Kui Zhao, Wei Gao, Wenqi He, Feng Gao, and Li Wang
- Subjects
Microbiology (medical) ,viruses ,medicine.medical_treatment ,Clinical Biochemistry ,Immunology ,Antibodies, Viral ,DNA vaccination ,Interferon-gamma ,Mice ,Immune system ,Adjuvants, Immunologic ,Vaccines, DNA ,medicine ,Animals ,Immunology and Allergy ,Neutralizing antibody ,Mice, Inbred BALB C ,Vaccines, Synthetic ,Vaccines ,biology ,Viral Vaccine ,virus diseases ,Viral Vaccines ,biochemical phenomena, metabolism, and nutrition ,Antibodies, Neutralizing ,Virology ,respiratory tract diseases ,Coronavirus ,Disease Models, Animal ,Vaccines, Inactivated ,Immunoglobulin G ,Inactivated vaccine ,Humoral immunity ,Leukocytes, Mononuclear ,biology.protein ,Alum Compounds ,Interleukin-2 ,Female ,Interleukin-4 ,Antibody ,Coronavirus Infections ,Adjuvant - 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.
- Published
- 2012
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