J Vet Sci.  2019 Jul;20(4):e32. 10.4142/jvs.2019.20.e32.

Generation and protective efficacy of a cold-adapted attenuated genotype 2b porcine epidemic diarrhea virus

Affiliations
  • 1ChoongAng Vaccine Laboratories, Daejeon 34055, Korea.
  • 2Department of Infectious Diseases, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea.
  • 3Animal Virology Laboratory, School of Life Sciences, BK21 plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Korea. changhee@knu.ac.kr

Abstract

The recent emergence and re-emergence of porcine epidemic diarrhea virus (PEDV) underscore the urgent need for the development of novel, safe, and effective vaccines against the prevailing strain. In this study, we generated a cold-adapted live attenuated vaccine candidate (Aram-P29-CA) by short-term passage of a virulent PEDV isolate at successively lower temperatures in Vero cells. Whole genome sequencing identified 12 amino acid changes in the cold-adapted strain with no insertions and deletions throughout the genome. Animal inoculation experiments confirmed the attenuated phenotype of Aram-P29-CA virus in the natural host. Pregnant sows were orally administered P29-CA live vaccines two doses at 2-week intervals prior to parturition, and the newborn piglets were challenged with the parental virus. The oral homologous prime-boost vaccination of P29-CA significantly improved the survival rate of the piglets and notably mitigated the severity of diarrhea and PEDV fecal shedding after the challenge. Furthermore, strong antibody responses to PEDV were detected in the sera and colostrum of immunized sows and in the sera of their offspring. These results demonstrated that the cold-adapted attenuated virus can be used as a live vaccine in maternal vaccination strategies to provide durable lactogenic immunity and confer passive protection to litters against PEDV.

Keyword

Attenuated vaccine; cold adaptation; porcine epidemic diarrhea virus; protection; whole genome sequencing
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