S1 domain of the porcine epidemic diarrhea virus spike protein as a vaccine antigen

Makadiya, Niraj; Brownlie, Robert; van den Hurk, Jan; Berube, Nathalie; Allan, Brenda; Gerdts, Volker; Zakhartchouk, Alexander

All the animal experiments were performed in the animal containment level 3 laboratories of VIDO-InterVac. All pigs were maintained and euthanized as per the protocol, approved by the University of Saskatchewan's Animal Research Ethics Board and adhered to the Canadian Council on Animal Care guidelines for humane animal use. Two commercial crossbred pregnant sows were used in this study. The sows were vaccinated intramuscularly on both sides of neck with either purified S1 protein (400 μg per dose) or saline mixed with TriAdj adjuvant [28] three times, 14 days apart (days 0, 14 and 28). Blood samples were collected for serum on days 0, 11, 28 and 35. Farrowing was induced at 16 days after the last vaccination. Colostrum samples were collected on the day of farrowing. Piglets were allowed to suckle their dams, and on the 4th day of their life they were orally challenged with live PEDV (3×10 2 TCID 50 per piglet). Clinical signs, diarrhea, death and weight of challenged piglets were monitored daily throughout the study. Blood samples of all the piglets were collected on the day of challenge for analysis. Rectal swabs were collected from each of the piglets daily for analyzing the presence of viral RNA by qRT-PCR.