Clin Exp Vaccine Res.  2016 Jul;5(2):132-137. 10.7774/cevr.2016.5.2.132.

An oral Aujeszky's disease vaccine (YS-400) induces neutralizing antibody in pigs

• Yang DK
• Kim HH
• Choi SS
• Hyun BH
• Song JY

• KMID: 2421560
• DOI: http://doi.org/10.7774/cevr.2016.5.2.132

Abstract

PURPOSE
Aujeszky's disease (AD) is an economically important disease affecting both wild and domestic pigs of the species Sus scrofa. A previous study yielded serological evidence of AD in Korean wild boars, which could spread AD to other animals. A new Aujeszky's disease virus (ADV) bait vaccine is required to prevent AD outbreaks in swine. In the present study, we investigated the safety and immunogenicity of a gE-deleted marker vaccine, strain YS-400, in young domestic pigs.
MATERIALS AND METHODS
The YS-400 strain was propagated in Vero cells, and the trial ADV bait vaccine (a vaccine blister in a matrix including an attractant) was prepared. Pigs were orally immunized with the vaccine (2 mL, 10(7.5) TCID(50)/mL) delivered using a syringe or in the bait vaccine. The animals were observed for 9 weeks after vaccination, and immunogenicity was assessed using a virus neutralization (VN) test and enzyme linked immunosorbent assay.
RESULTS
The YS-400 strain was non-pathogenic to pigs when given orally and induced high VN titers (1:32-1:128) 6 weeks post-administration. Of the pigs given the ADV bait vaccine twice or three times, 40% were seropositive by 2 weeks, and 100% were seropositive by 7 weeks after the first dose. Pigs that consumed the AD bait vaccine three times developed VN titers that were slightly higher than those of pigs given the vaccine twice.
CONCLUSION
Domestic pigs given the trial ADV bait vaccine exhibited no adverse effects and developed high VN titers against ADV, indicating that the YS-400 strain is safe and can prevent ADV infection in domestic pigs.

Keyword

Aujeszky's disease virus; Immunity; Oral vaccine

MeSH Terms

Animals
Antibodies, Neutralizing*
Blister
Disease Outbreaks
Enzyme-Linked Immunosorbent Assay
Herpesvirus 1, Suid
Pseudorabies*
Sus scrofa
Swine*
Syringes
Vaccination
Vero Cells
Antibodies, Neutralizing

Figure

• 

  Fig. 1 Schematic diagram of construction of the recombinant Aujeszky's disease virus (ADV) vaccine strain. The YS-400 strain lacks parts of the wild-type TK and gE genes and carries recombinant interleukin 2 (IL2) and beta galactosidase (βgal) genes. The vaccine is based on the wild-type Yangsan ADV strain.

• 

  Fig. 2 Immunogenicity of the YS-400 strain given via the oral route using a syringe. Six young pigs were vaccinated twice with 2 mL of the YS-400 strain and developed virus neutralization (VN) titers of 1:8-1:128 against Aujeszky's disease virus by 2 weeks after vaccination. All control pigs were negative in terms of VN titer throughout the experiment.

• 

  Fig. 3 The trial Aujeszky's disease bait vaccine and the immunogenicity thereof in domestic pigs. The pig is consuming a bait vaccine containing the YS-400 strain (A). The mean virus neutralization (VN) titers (B) and enzyme linked immunosorbent assay titers (C) in groups vaccinated twice (group 1) or three times (group 2) and the seropositive rates attained by each group (D).

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