Evaluation of the Efficacy of a Recombinant Adenovirus Expressing the Spike Protein of Porcine Epidemic Diarrhea Virus in Pigs

Liu, Xinsheng; Zhao, Donghong; Zhou, Peng; Zhang, Yongguang; Wang, Yonglu

week-old pigs that were tested seronegative for PEDV by a commercial enzyme-linked immunosorbent assay (ELISA) kit (Biovet, Canada) were obtained from a commercial pig farm with no previous herd history of PED outbreak or PEDV vaccination. All of the pigs were raised in the laboratory animal facility at the Lanzhou Veterinary Research Institute, and each group of pigs was housed in a different room. e vaccination doses were determined based on previous published studies of the PEDV S gene-based recombinant virus vaccine [22] [23] [24] . As shown in Table 1 , all piglets were randomly divided into four groups (G1-G4) each with five pigs. Groups 1-3 were immunized IM with 10 10 PFU/mL Ad-blank, 10 10 PFU/mL rAd-PEDV-S, and 2 mL of the commercial PEDV inactivated vaccine (inactivated virus of a genotype GIIb strain; virus titer before inactivation ≥ 10 7 TCID 50 ). Group 4 was immunized IM with phosphate-buffered saline (PBS) as a mock control. All pigs were first immunized at 0 days post vaccination (dpv) and received booster immunizations at 21 dpv under the same conditions. Serum samples from all groups were collected at 0, 7, 14, 21, and 28 dpv for antibodies.