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

Purified S1 Fig. 2 Expression of the recombinant PEDV S1 protein in insect Sf9 cells. a A small scale S1 protein expression experiment was performed by infecting Sf9 cells with recombinant baculovirus expressing PEDV S1 gene. Cell culture media were collected on indicated days post-infection and analysed by Western blotting using anti-his antibody. b Large scale S1 protein purification was performed on cell culture medium of the cells infected with recombinant baculovirus at day 7 post-infection, and the purified protein was anyalzed by SDS-PAGE and stained by Coomassie Blue. Medium from un-infected cells served as a negative control. Numbers on the left indicate the protein molecular marker size in kDa Fig. 1 Expression of the recombinant PEDV S1 protein in PichiaPink Pichia pastoris. a A small scale S1 protein expression experiment was performed, and samples of culture medium were collected on indicated days post-induction and detected by Western blotting using anti-his antibody. b A large scale S1 protein purification was performed from the yeast cell supernatant at day 4 post-induction, and the purified protein was anyalzed by staining of SDS-PAGE by silver nitrate. Medium from the un-induced cells served as a negative control. Numbers on the left indicate the protein molecular marker size in kDa intramuscularly with adjuvanted S1 recombinat protein produced from HEK 293 T cells. The humoral immune responses elicited by the subunit vaccine were examined by ELISA and serum neutralization assay. The vaccinated sow showed an increase in S1-specific serum IgG titer after the first, second and third vaccination (Fig. 5a) whereas no increase was noticed in the control sow. Furthermore, in contrast to the control sow, vaccinated sow demonstrated detectable serum neutralizing-antibody titers at day 11